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Medical Forum / General / Vision / December 2005Could all my myopia be pseudomyopia? See accomodative amplitude
Age Amplitude of Accommodation 5 16.00 diopters 10 14.00 diopters 15 12.00 diopters 20 10.00 diopters 25 8.50 diopters 30 7.00 diopters 35 5.50 diopters 40 4.50 diopters 45 3.50 diopters 50 2.50 diopters 55 1.75 diopters 60 1.00 diopter 65 0.50 diopter 70 0.25 diopter 75 0.12 diopter I am almost 25 yet I have only 2.5 diopters of accomodation! This would mean I have 5.5 diopters of pseudomyopia, making me a mild latent hyperope! Of course I doubt I have anywhere near this much pseudomyopia. Myopia is in our family genes and if pseudomyopia were suspect, my mom wouldnt be a -8. Could even a small amount of pseudomyopia cause accomodative dysfunction due to cilinical muscle spasms? I remember I got my first -1 glasses when I was 12, it kept getting worse till im now a -5! I suspect I have an easy one diopter pseudomyopia and wouldnt be supprised if its considerabily more. When I wear strong glasses(my full pescription) things become more blurry when I take them off or go to weaker glasses. After a few hours things clear a little. My parents and optometrist dont believe in eye exercises, but its been working for me. I have achieved at least a half diopter improvement since I started several months ago. I may have a long way yet to go. I was just thinking something disturbing: what if someone gets lasik and he has any pseudomyopia and ends up plano? He will be a hyperope as he gets older and presbyopia sets in! I sure hope they give everyone cycoplegic refractions before refractive surgury! > Could even a small amount of > pseudomyopia cause accomodative dysfunction due to cilinical muscle > spasms? Have you had a cycloplegic exam? What was your cycloplegic refraction and how much did it differ from your manifest refraction? It seems reasonable to me to suspect that you are overminused but the cycloplegic results would be definitive. > was just thinking something disturbing: what if someone gets lasik and > he has any pseudomyopia and ends up plano? He will be a hyperope as he > gets older and presbyopia sets in! I sure hope they give everyone > cycoplegic refractions before refractive surgury! Yes. LASIK patients get a cycloplegic exam before surgery. >> Could even a small amount of >> pseudomyopia cause accomodative dysfunction due to cilinical muscle [quoted text clipped - 11 lines] > >Yes. LASIK patients get a cycloplegic exam before surgery. As a *patient* who has severe accommodative spasms (pseudomyopia is a part of this), here's my $0.02: If you think you're dealing with this, it's my opinion that a strong cycloplegic (Cyclogyl/Homatropine/Atropine) is the only way to go. I had roughly 3d (or more) of accommodative amplitudes "locked" up in spasm for years (causing pain, nausea, dizziness, and fatigue). Cycloplegic refractions with the usual drugs (Midriacyl, Epinephrine, Cyclomidryl) showed the same Rx as a dry refraction, causing doctors to conclude that I "simply" had ZERO accommodative amplitudes. Only a four-day regimen of Atropine truly "unlocked" it. Before that Atropine regimen, though, I had a strabismus surgery to correct crossing eyes. Eye alignment and accommodation are linked. We overcorrected, via the surgery, because we hadn't uncovered all of the hyperopia. Now, my eyes turn substantially *out*, forcing my (dysfunctional) accommodative system to turn them in, and driving accommodation that (causes nasty symptoms and that) I'm ill-equipped to sustain. To your point: Had we used the Atropine prior to the surgery (who knew?), we'd have arrived at different numbers and done the surgery to a lesser degree. Good luck!  SignatureLive simply so that others may simply live I remember having one when I was a little boy. Maybe they thought any myopia I had was pseudo? I do remember everything nearby being very blurry and when they let me choose a toy out of the box I couldnt properly see it even at arms length! "Yes. LASIK patients get a cycloplegic exam before surgery." I sure hope every one of them do! "If you think you're dealing with this, it's my opinion that a strong cycloplegic (Cyclogyl/Homatropine/Atropine) is the only way to go" Is this dangerous in any way? should I assume most optometrists have some of that cycloplegic agent in their office to administer? How long do/did the effects last? if im gonna get a cycloplegic refraction, my best bet is to go with one of those to really rule out pseudomyopia. "Only a four-day regimen of Atropine truly "unlocked" it." you got it everyday for 4 days? "Several different possibilities exist other than presbyopia, which is purely age-related." I still see many people say they developed presbyopia early, some in their teens! Neil Brooks wrote: >>"If you think you're dealing with this, it's my opinion that a strong >>cycloplegic (Cyclogyl/Homatropine/Atropine) is the only way to go" >Is this dangerous in any way? should I assume most optometrists have >some of that cycloplegic agent in their office to administer? How long >do/did the effects last? if im gonna get a cycloplegic refraction, my >best bet is to go with one of those to really rule out pseudomyopia. Not that I'm aware of. The problems with cycloplegics -- nearly all cycloplegics -- comes with LONG-term use, and comes from the preservative, Benzalkonium Chloride. Controlled use, in an eye doctor's office, has never caused any real issues, to my knowledge. >>"Only a four-day regimen of Atropine truly "unlocked" it." >you got it everyday for 4 days? Yeah. Actually, it gets worse. Because the accommodative spasm returned when I went back to work, I eventually wound up using Atropine twice a day, every day. Long story. Not particularly cheery, either.... At your age, and in your case, if strong cycloplegia indicates you have accommodative spasm, I'd recommend finding a good vision therapist to increase your accommodative amplitudes and facility. You also may benefit from either bifocals or from (you're MYopic, right) not wearing your glasses when reading (forgive me if you know this or if it was covered already on s.m.v). Good luck! SignatureLive simply so that others may simply live I am delighted to see that Neil has just addressed this. In my experience, the pseudomyopic component of myopia is typically no more than one or two diopters. As Neil said, accommodation is often recruited by the convergence system in cases of convergence insufficiency. In fact, some binocular vision texts specifically state that over-minusing can help patients with CI. Then, there are patients who just have a low accommodative amplitude, and others who have a high AC/A ratio. Several different possibilities exist other than presbyopia, which is purely age-related. DrG > Age Amplitude of Accommodation > [quoted text clipped - 13 lines] > 70 0.25 diopter > 75 0.12 diopter Not sure about that table. I think it's too generous between ages 40 and 60. At least from my practice experience. Some of it may be depth of focus, maybe something to do with the way it was measured. > I am almost 25 yet I have only 2.5 diopters of accomodation! This is pretty unusual. Again, I'm thinking there might be a problem with the way it's being measured. You might also be a good candidate for some vision therapy, as you may just not have "learned" the ability to focus way up close. How was your 2.5 D. measured? And was it monocularly or binocularly? This would > mean I have 5.5 diopters of pseudomyopia, making me a mild latent > hyperope! Of course I doubt I have anywhere near this much > pseudomyopia. Not a chance. Myopia is in our family genes and if pseudomyopia were > suspect, my mom wouldnt be a -8. Could even a small amount of > pseudomyopia cause accomodative dysfunction due to cilinical muscle > spasms? I don't think so. Ciliary muscle spasms would cause MORE accommodation, not less. > I remember I got my first -1 glasses when I was 12, it kept getting > worse till im now a -5! I suspect I have an easy one diopter > pseudomyopia and wouldnt be supprised if its considerabily more. When I > wear strong glasses(my full pescription) things become more blurry when > I take them off or go to weaker glasses. After a few hours things clear > a little. That's normal. > My parents and optometrist dont believe in eye exercises, but its been > working for me. I have achieved at least a half diopter improvement > since I started several months ago. I may have a long way yet to go. What kind of exercises? I > was just thinking something disturbing: what if someone gets lasik and > he has any pseudomyopia and ends up plano? He will be a hyperope as he > gets older and presbyopia sets in! I sure hope they give everyone > cycoplegic refractions before refractive surgury! Of course they do. And ending up plano is usually the goal, except for those over age 40 who want a bit of monovision (myopia in one eye to help with the presbyopia, which surely will set in, if the patient lives long enough. w.stacy, o.d. I agree. Way too generous especially for the higher ages. I think that table is too generous, period. I can focus up close fine without glasses. I am more interested in resolving my probable pseudomyopia than having super accomodation. I measured my accomodation by the difference between minimum and maximum points. For example, my -5 left eye has a nearpoint of 20cm but I can zoom in down to 13cm. This means im using 2.5 diopters of accomodation. With my -5.5 glasses I got several months ago, the 16" nearpoint snellen is a little blurry. To read anything with strong glasses on, they have to be removed or peek under. so ciliary muscle spasms and pseudomyopia are two different things? pseudomyopia locks in some of your accomodation so less is available. as for eye exercises, theres many kinds. Palming is very popular. Plus lense is another popular one. T-glasses has been mentioned in my book. This means you undercorrect yourself on purpose at all times which is what im doing. For the computer and house I wear -3.25 glasses and I see perfectly well near and intermediate. When I go out of the house I wear -4.25s which only slightly undercorrect me. Dont worry, I dont drive and if I do, I would wear the power that gives me my 20/30 BCVA. I am slowly resolving my pseudomyopia by undercorrecting myself. monovision isnt for everyone and I still would see blurry in one eye at all times which is very annoying! I much prefer both eyes to be equal even if both are undercorrected. "Atropine twice a day, every day. Long story. Not particularly cheery, either...." ouch what happened? "You also may benefit from either bifocals or from (you're MYopic, right) not wearing your glasses when reading (forgive me if you know this or if it was covered already on s.m.v)." I already take my glasses off to read, its clearer that way. I use a method to attempt to improve my vision, read at the point of slight blur which should relax your eyes. "By the way, if you have increased you accommodation by 1/2D in several months, you can't be spending much time on it." I improved my vision by 1/2d by reducing my pseudomyopia. This means my distance vision is a little less blurry now. I have been bugging my parents to take me for an eye exam and ill ask the optometrist for a cycoplegic refraction too. Problem is I need to convince them theres something wrong with my eyes! you're 23 bozo, make an appointment yourself. Or are you a 13yo pretending??? "CatmanX" sez to a presumed young person: > you're 23 bozo, make an appointment yourself. Or are you a 13yo > pretending??? Catman, you are not seeming to be very supportive. I hope you are not mistreating your cat(s). Do you actually have a cat, or some cats? Can you post a picture? My cat, Muffin Man, is here: http://home.att.net/~muffkat/ -- dicky Sorry Dick. This twit is posting total nonsense over at alt.lasik.eyes about how he is going to have 5 procedures to get Lasik, how he has high order aberrations, no accommodation, how he determines his script by how far away from his face he can see and converting to dioptres etc. He keeps saying his mum and dad won't let him get an eye test and won't let him do eye exercises because they don't believe in it. I have been telling him for weeks to get his eyes tested and we can discuss the facts, but he doesn't do this and continues to talk total drivel on subjects he knows nothing of. I would have some sympathy, and solutions if this clown actually did something proactive and not sat in front of a computer waffling about his prescription, which he doesn't know, by the way. So no, I am not very sympathetic, and given the way he talks, he sounds more like a 13 yo as any self-respecting 23yo as Ace says he is could make an appointment to get an eye test, drive to the optometrist and find out what is going on with his eyes. dr grant "about how he is going to have 5 procedures to get Lasik" Its hypothethical and its two, not five. Get a small amount of correction in one eye and if it works well correct the other eye and if it works well, enhance the first eye that got the small correction. If lasik doesnt work for you, better to stop after one eye and since you got a small correction, anisometropia wont be an issue. "how he has high order aberrations" everyone does. I just have it worse and can only be corrected to 20/30 read this http://www.grendahl.com/wavefront/wavefront_system.html "no accommodation" wrong! I can accomodate, just not as well. My dad spoke to the optometrist when he took grandma there and he just says im too young for presbyopia but he doesnt know why my accomodation isnt very good. He also says he can give me a cycoplegic refraction but it wont resolve anything except give me info. Well I want to know how much pseudomyopia I have so I can do something about it. "how he determines his script by how far away from his face he can see and converting to dioptres etc." http://www.pc.ibm.com/ww/images/healthycomputing/graph8.gif a +2, +3, +5 whatever lense is in focus at 1/2, 1/3, 1/5, whatever meters. If my eye has +5 diopters too much focusing power, light is converged to 20cm focal point. By measuring the exact point where text becomes perfectly clear, I can tell my pescription. My left eye is getting 20cm which means its -5 and my right eye is seeing a little further at 22cm so it must be -4.5! "He keeps saying his mum and dad won't let him get an eye test and won't let him do eye exercises because they don't believe in it." I do eye exercises anyway, they cant stop me. My eyes are my own business. I can talk dad into getting me an eye exam. "like a 13 yo as any self-respecting 23yo as Ace says he is could make an appointment to get an eye test, drive to the optometrist and find out what is going on with his eyes." well I dont drive, not interested in driving. Im trying to get in shape so I can bike for transportation but right now im not in shape to bike far. >"about how he is going to have 5 procedures to get Lasik" > [quoted text clipped - 5 lines] > > That's a novel approach. We are talking surgery here, real surgery both times. Almost like saying ok put in an artificial knee, but use a cheap model so if I like it but want better, I can have it redone. Or if I don't like it I can leave the turkey in there. >"how he has high order aberrations" > [quoted text clipped - 3 lines] > > That web site is very nice razzmatazz, but the truth is, you don't know how much of your problem is higher order and how much is lower order. And the surgeons I work with are backing off wave front as we speak. Its promises are not being realized in most patients, and the larger ablations are riskier. >"no accommodation" > [quoted text clipped - 6 lines] > > Get the info. and have the cyclo. Maybe not by this guy who thinks it won't resolve anything. It might resolve a LOT but you'll never know unless you have it. >"how he determines his script by how far >away from his face he can see and converting to dioptres etc." [quoted text clipped - 9 lines] > > You'r neglecting the all important OTHER LOWER ORDER ABERRATION, astigmatism, completely!!!! Your method only works if you are totally free of astigmatism. How do you know you are stigmatic? w.stacy, o.d. "That's a novel approach. We are talking surgery here, real surgery both times. Almost like saying ok put in an artificial knee, but use a cheap model so if I like it but want better, I can have it redone. Or if I don't like it I can leave the turkey in there." Bad analogy. Lasik is permaent, knee surgury isnt. It doesnt matter what you put, if you dont like it, out it goes. With lasik you can simply get enhanced(redo) but not undo it. I guess someone people dont believe the having one eye done at a time approach. I dont feel like lecturing this, next topic. "That web site is very nice razzmatazz, but the truth is, you don't know how much of your problem is higher order and how much is lower order. And the surgeons I work with are backing off wave front as we speak. Its promises are not being realized in most patients, and the larger ablations are riskier." I have been to many optometrists and gotten many eye exams. None could get me to see a single letter on the 20/20 line and the 20/25 was iffy with guessing and errors. All my refractive error was already corrected for. I see some halos and starbursts at night. Your saying they no longer do wavefront? regular lasik will induce even more aberrations. If larger ablations are risky then those with big pupils probably shouldnt get lasik at all. "Get the info. and have the cyclo. Maybe not by this guy who thinks it won't resolve anything. It might resolve a LOT but you'll never know unless you have it." see my thread specifically on this "Ok dad will take me to an optometrist or ophthamologist for an exam IF...." "You'r neglecting the all important OTHER LOWER ORDER ABERRATION, astigmatism, completely!!!! Your method only works if you are totally free of astigmatism. How do you know you are stigmatic?" http://library.thinkquest.org/26313/ast.htm http://www.lea-test.fi/ru/vistests/instruct/astigmaw/images/astigmw1.gif > All my refractive error was already corrected >for. I see some halos and starbursts at night. Your saying they no >longer do wavefront? regular lasik will induce even more aberrations. >If larger ablations are risky then those with big pupils probably >shouldnt get lasik at all. > I'm saying they are backing off; doing less of it, because it's not delivering exactly as advertised. Some are still being done. I saw one this week who had wave front done last week. One eye was pretty good, the other was not as good as most ordinary lasik delivers. I rest my case, but you're right, big pupils spell trouble. I still say if you haven't had topography, you don't know the extent of any higher order abs you might or might not have. Re o.d.s prescribing drops and other meds, I submit we do it all the time and are arguably more up to date than most o.m.d.s on it because we are required to take much more continuing education on the subject every year than they do, at least in California where I practice. No question they are more up to date on surgery, which is what they do best, although in LASIK optometrists are far more likely to be conservative and careful in guiding patients than are LASIK surgeons themselves. There's that little financial incentive that keeps getting in the way of good judgement... > "I'm saying they are backing off; doing less of it, because it's not delivering exactly as advertised. Some are still being done. I saw one this week who had wave front done last week. One eye was pretty good, the other was not as good as most ordinary lasik delivers. I rest my case, but you're right, big pupils spell trouble." So surgeons are going back to classic lasik? I still think wavefront is a better bet, it has better odds for a good result. Think of it as rolling 3 dice(wavefront) or 2 dice(classic) with wavefront your numbers will be higher most of the time than classic. Of course you can roll a low number with wavefront or a high number with classic. The bottom line is have relistic expectations before getting lasik or other RS. I find that many people fall a little below their BCVA and give up some quality of vision, especially at night. You may end 20/20 shortly after lasik but come back in 3 years and many wont be 20/20 anymore. A good relistic expectation is improved UCVA and reduced dependancy on glasses. This is percisely what lasik surgeons are saying. They even put in writing all over. Let me quote: What can I expect from LASIK? Laser vision correction surgery has been proven to be very successful for helping individuals reduce their dependence on glasses and contact lenses. However, the degree of improvement will vary among individuals. You, as are all individuals seeking vision correction, are concerned with reaching a satisfactory outcome. Although Emory Laser Vision cannot promise patients 20/20 vision, most with mild to moderate prescriptions do reach this or are close to 20/20 vision. While visual acuity is a common test for vision, it is not the only measurement used. Patients should not focus on achieving a 20/20 vision as a “perfect” vision, the realistic expectation is to reduce dependency on glasses or contact lenses. see? They even tell you this! If anyone promises 20/20 vision, they are setting you for disapointment. The only thing promised(to a high degree) is youll end up closer to plano for moderate and especially severe myopes. Low myopes dont even always end close to plano because their pescription is so slight, they may still end up the same, be overcorrected and have induced astigmastim. For this reason, I tell people NOT to bother with lasik if they have less than -2 diopters myopia. Thier UCVA is already fairly good and they have little more to gain. On the other hand a -8 is functionally blind so even if he ends 20/40 he will be thrilled! For him, this means no more thick glasses, no more being "blind" without glasses. "I still say if you haven't had topography, you don't know the extent of any higher order abs you might or might not have." http://img220.exs.cx/img220/4051/pic0082up.jpg I have gotten comments about the orange. Feel free to add your own. I see better in the left eye than the right. "although in LASIK optometrists are far more likely to be conservative and careful in guiding patients than are LASIK surgeons themselves. There's that little financial incentive that keeps getting in the way of good judgement..." also ask lasik patients themselves and post questions online before getting lasik. I have asked tons of questions and learned so much about it. Lasik isnt for me due to various reasons plus id still need glasses. >I still think wavefront is >a better bet, it has better odds for a good result. Think of it as >rolling 3 dice(wavefront) or 2 dice(classic) with wavefront your >numbers will be higher most of the time than classic. Of course you can >roll a low number with wavefront or a high number with classic. To me it's significant that the ablations are much larger and deeper with wave front than with classic, so you're further weakening the cornea, with less remaining material to work with on re-treatments. Theoretically, you're right, but practically, you may be wrong, and the surgeons I work with seem to favor more caution with wave front at this time. > The >bottom line is have relistic expectations before getting lasik or other [quoted text clipped - 3 lines] >good relistic expectation is improved UCVA and reduced dependancy on >glasses. I'll go along with that, although I have plenty of patients who remain 20/20 UCVA years afterwards. I've also got a good number who need glasses (weak ones, of course) to get 20/20 and don't want to bother with retreatment, because retreatment is another REAL surgery, and healing goes back to day 1 post op again. > If anyone promises 20/20 vision, they are >setting you for disapointment. Promising an outcome is always risky business. > Low myopes dont even always end close to plano because >their pescription is so slight, they may still end up the same, be >overcorrected and have induced astigmastim. They could, but the vast majority of low myopes end up very near plano, which is what they want. Overcorrection is of course to be avoided like the plague. The ablations are very minor, and PRK is enjoying a resurgence esp. with low myopes, because the risks are so low and the outcomes so good. >For this reason, I tell >people NOT to bother with lasik if they have less than -2 diopters [quoted text clipped - 4 lines] > > I've never run into anyone who was thrilled with 20/40. That's an awful outcome, assuming he/she was 20/20 best corrected before LASIK. Funny, but I often give the opposite advice, except for really low myopes. The more myopia above -6.00, the more cautious I get. I don't recommend LASIK for anyone over -10.00. Between -1 and -2.00 AND under 30 years old, it's pretty much a sure thing, at least as much a sure thing refractive surgery ever can be. w.stacy, o.d. "To me it's significant that the ablations are much larger and deeper with wave front than with classic, so you're further weakening the cornea, with less remaining material to work with on re-treatments. Theoretically, you're right, but practically, you may be wrong, and the surgeons I work with seem to favor more caution with wave front at this time." For low myopes, wavefront works very well. Wavefront isnt reccomended if you are more than -5 or -6 or if you have thin corneas. I know someone who was given the choice of wavefront or regular lasik with the catch if he gets wavefront, there wont be enough cornea for an enhancement and if he gets the regular kind, he can get one enhancement. He took the regular kind and not only did he not need an enhancement, he ended 20/20 with only a small loss in night vision. For high myopes, they probably are better off getting phakic IOLs anyway as compared to removing large amounts of cornea with low chance of 20/20 or plano. "I've also got a good number who need glasses (weak ones, of course) to get 20/20 and don't want to bother with retreatment, because retreatment is another REAL surgery, and healing goes back to day 1 post op again." This is why lasik is advertize to reduce(key word here!) dependancy on glasses. To promise perfect vision and to never need glasses is an unrealistic claim and would led to disapointment. But to just say reduced dependancy means you cant be dissapointed if you still need glasses because they specifically said "reduced" Many people dont bother getting an enhancement, especially not years down the road if they regress a bit or their eyes get a little worse. They may only need glasses occasionally so hence not worth the risk. "They could, but the vast majority of low myopes end up very near plano, which is what they want. Overcorrection is of course to be avoided like the plague. The ablations are very minor, and PRK is enjoying a resurgence esp. with low myopes, because the risks are so low and the outcomes so good." low myopes are near plano to begin with so to spend $5000 and take a risk with their eyes seems silly to me when their dependancy on glasses is slight to begin with. My brother is 20/60 uncorrected and rarely even wears glasses. Of course if he got surgury he could compare his 20/60 UCVA to his new UCVA but if he gets overcorrected or induced astigmastim or any other complication, he may still not have clear vision, not even with glasses. I know a number of people with 20/40 to 20/70 vision who only wear glasses for driving or movies. They dont feel that surgury is worth the expense and risks for such little improvement when they already dont really need glasses to begin with. "I've never run into anyone who was thrilled with 20/40. That's an awful outcome, assuming he/she was 20/20 best corrected before LASIK." The snellen chart does not tell the whole story. Heck Ive seen lots of people who ended up even with 20/20 who werent happy with the vision quality wise. 20/40 is quite good vision if the quality is good. I see 20/40 with -4.25 glasses and everything is quite sharp. of course I cant be corrected much better so I dont have much to compare. People think whatever they saw was normal and what everyone else saw till their get glasses for the first them then are totally amazed at the difference. Ive been there. I didnt even think I had a vision problem but I begin to suspect something was up when my father and my friends could see at least twice as far as me. Things also looked a little clearer when I squinted. Reguardless, if the 20/40 they end up is of good quality, they would only need glasses to drive and maybe watch movies. They can keep their near vision and stay out of reading glasses for some time. Many surgeons are reluctant to even give an enhancement if your seeing well enough to legally drive due to taking another risk with enhancement and possibily ending up worse. I know many sad stories like that. The origional surgury went well but the enhancement didnt. If they still insist to enhance, only do one eye at a time, anisometropia isnt an issue. "The more myopia above -6.00, the more cautious I get." You may want to discuss IOLs. Those have become popular for higher myopes and im seeing lots of -10s, -8s, some even -6s get that instead. Also high myopes often regress and many dont have enough cornea or dont want to risk enhancement. Trading their thick full time glasses for thin partime glasses is a probable and relistic expectation. Some say no way, others are delighted for *any* improvement. Hey if I was a high myope and had no other contrindictions, I would be really happy instead of waking up to one big blur, things are only a smidgen blurry and instead of cokebottles full time, I can get paper thin glasses when I go out of the house. I will also be glad I can put off reading glasses! "Between -1 and -2.00 AND under 30 years old, it's pretty much a sure thing" till presbyopia sets in then they traded their distance glasses for reading glasses. Sadly most people arent aware of this that a little myopia will be your friend and you wont need glasses except for distance like driving, sports, movies, etc. I do NOT reccomend RS if they are less than -2. Some who are active in sports and outdoors of course have more reason for RS > You may want to discuss IOLs. Those have become popular for higher > myopes and im seeing lots of -10s, -8s, some even -6s get that instead. I've been pushing iols for presbyopic hyperopes and pre-presbyopic high hyperopes, but am wary of doing so for myopes, due to the risk of retinal detachment. Phakic iols are promising, but carry their own risks, and I consider them to be "experimental" at this point. w.stacy, o.d. Its true theres a risk of retina detachment, but for high myopes, lasik may not be a possibility and even if it is, its probably just as risky anyway. If the suction cup is used, this can detach the retina. If PRK is used, you can develop haze. Many of the complications are from high myopes. High hyperopes and high astigmatics also are at increased risk of lasik. Do you believe in a partial lasik(or better yet, surface ablation) correction for high myopes? This means someone whos like -10 to -12 can end up as a low myope, generally -1 to -3 diopters. No. As I said earlier, the higher the myopia (above 6 D.) the more cautious I get. Obviously corneal thickness and pupil size are crucial. e.g. I'm ok with -8, 600 mu corneas, and 4 mm pupils, and wouldn't dream of it if the cornea was 500 mu and the pupils are 7 mm. I can't see much benefit from half corrections, and 90% ones make even less sense to me. I'm telling a lot of people to wait for a couple of years until we get more numbers on phakic iols. w.stacy, o.d. > Its true theres a risk of retina detachment, but for high myopes, lasik > may not be a possibility and even if it is, its probably just as risky [quoted text clipped - 4 lines] > ablation) correction for high myopes? This means someone whos like -10 > to -12 can end up as a low myope, generally -1 to -3 diopters. I still see many high myopes with thin corneas and large pupils get lasik or prk. Unfortunately large pupils are contrindicted in phakic IOLs as well. Those large pupil people are probably out of luck and must deal with glasses and/or contacts. Better than losing some vision after refractive surgury anyway or ending up undercorrected and still needing glasses anyway with worse vision. I remember in the past some surgeons were doing lasik on myopes around -15 diopters! Of course all of them had ruined vision. Its been found out the hard way that -10 is the pratical limit but in many cases, -6 to -8 is all that can be done or itll become too risky. I know a woman who was a -9 and her surgeon told her shes too nearsighted for a full correction so she will still need thin glasses. Needless to say she was like forget lasik if I still need glasses! Others dont care for a partial correction, especially if they do alot of near work. Reducing their dependancy on glasses is great and not needing reading glasses. I for one would not mind a partial correction. I dont think lasik is for me but ive got interest in ortho-k which if it doesnt work out, I simply stop wearing those nightly contacts and in a few weeks ill revert back to the way things were. No surgury done, nothing permaent either. Ill probably go for an undercorrection of -1 to -1.5 diopters so I dont need reading glasses much. That and ortho-k cant fully correct me anyway. > I still see many high myopes with thin corneas and large pupils get > lasik or prk. Yeah, I see tens of thousands every day. Well, maybe just a few hundred. OK, a dozen. Maybe just one. So, it's just aunt Susie, what's the big deal? Maybe I don't know how to measure corneal thickness, I still know how to make stuff up, don't I? SignatureDan Abel dabel@sonic.net Petaluma, California, USA > Bad analogy. Lasik is permaent, knee surgury isnt. It doesnt matter > what you put, if you dont like it, out it goes. With lasik you can > simply get enhanced(redo) but not undo it. I guess someone people dont > believe the having one eye done at a time approach. I dont feel like > lecturing this, next topic. I take it that you haven't had a lot of knee surgeries. Or Lasik. One eye at a time sounds like a plan to me. There is debate about that here, though. Two surgeries on the same eye just doesn't seem like a good idea. YMMV. SignatureDan Abel dabel@sonic.net Petaluma, California, USA > One eye at a time sounds like a plan to me. There is debate about that > here, though. Two surgeries on the same eye just doesn't seem like a > good idea. YMMV. In the early days of LASIK, one eye at at time was done, but there were so few operative complications that the big complication of having extreme anisometropia during the intraoperative period was the determining factor in everyone going to bilateral procedures as the method of choice. Still, there are times when monocular procedures are preferred. One such case would be the original poster of this thread. I would recommend he go one eye at a time, although I'm not much in favor of the major undercorrection he proposed except for people over 35 years old (in anticipation of monovision correction). w.stacy, o.d. > "about how he is going to have 5 procedures to get Lasik" > [quoted text clipped - 3 lines] > lasik doesnt work for you, better to stop after one eye and since you > got a small correction, anisometropia wont be an issue. I heard a worse idea once. I don't remember what it is, though. Maybe I'll remember later. If I'm lucky, I won't. :-( SignatureDan Abel dabel@sonic.net Petaluma, California, USA Did you ever hear the old saying: "a little knowledge is a dangerous thing."???? You have little knowledge!!!!! Stop boring us with your concerns for things that don't exist and get your eyes tested properly. It is really simple. By the way, if you have increased you accommodation by 1/2D in several months, you can't be spending much time on it. I can get that in about 2 minutes with any patient, including 85 year olds. After several months, you should be able to do anything you want. Like I said, get your eyes tested proerly, get a diagnosis and get treatment. dr grant Dear Acema, Could all my myopia be pseudomyopia? In its initial phase, your all your myopia (say -1.0 diopters) could have been pseudo-myopia -- which converts to "real myopia" once you begin wearing a minus lens all the time. www.myopiafree.com Just one man's opinion. Best, Otis Thats what I thought and that seems to be where most people start off and if they do things wrong, their eyes grow longer as an adaption mechanism to make near work easier. The worst thing you can do is use a minus lense for near work. If you wear contact lenses, use reading glasses over them. People dont use their eyes right so they get ruined. I am trying to undo as much damage as I can. Lets say its found out I have -1.5 diopters in pseudomyopia, can I improve a little beyond that? I dont think much can be done about axial myopia > Thats what I thought and that seems to be where most people start off > and if they do things wrong, their eyes grow longer as an adaption [quoted text clipped - 4 lines] > have -1.5 diopters in pseudomyopia, can I improve a little beyond that? > I dont think much can be done about axial myopia That's an attractive misconception that does not explain the people who get -1.50s and NEVER get worse, even though they wear "the full minus" full time, nor does it explain the -6 and higher people who never wore glasses or contacts (I even ran into a -9.00 18 year old who had never worn glasses or contacts). The fact that all myopia progresses for a time, then stops progressing regardless of the amount of spectacle wear also contradicts it. It's convenient to blame the glasses for this, but it's a classic case of the logical fallacy of post hoc propter hoc. The fact is that your recommended regimen rarely seems to work in practice. If you have 1.5 pseudo, you don't have to do anything. It will correct itself, since it's not really there by definition. And you are right, structural myopia cannot be improved by not wearing glases, or by wearing them less, or by not wearing them at all. This has been proven. There is a psychological adaptation that myopes can make by going without their spec for a few days that makes them feel their eyes have improved, but every time you put them in the chair they still have the same unaided acuity and the same refraction. This adaptation has given rise to much quackery over the years, some of which has actually harmed people, which is why people like me tend to spend time trying to expose it. w.stacy, o.d. "That's an attractive misconception that does not explain the people who get -1.50s and NEVER get worse, even though they wear "the full minus" full time" You are perfectly correct, but then the majority do get worse. Besides if someone was only a -1.5, glasses would make no difference and just result in eyestrain for close work even if the eyes dont get worse. There are some low myopes who for some reason wear glasses even for the computer, eating, reading and thats a bad thing, results in eyestrain and in most cases, worsening of eyes due to pseudomyopia and/or axial myopia. "nor does it explain the -6 and higher people who never wore glasses or contacts (I even ran into a -9.00 18 year old who had never worn glasses or contacts)." How do they function like that? They wont see a thing more than mare inches from their eyes. They wont be able to see the board in school, drive or do most things. The only explanation is maybe they didnt even know they had a vision problem and got by fine being at home all their lives, almost never going out, doing lots of reading for entertainment and knowlege. "The fact that all myopia progresses for a time, then stops progressing, It's convenient to blame the glasses for this" Well, its been said that glasses will help your myopia progress faster and longer. Of course one may need glasses for some functions but what one can do is undercorrect himself whenever possible or wear bifocals. Ive seen bifocals prescribed to children to slow or stop their galloping myopia. If you are a low myope and can function without glasses, do so then. I find it strange that my friends who dont wear glasses never developed much myopia while those who did rapidly got worse. Alot of my friends are around a -1 and from 20/25 to 20/70 UCVA. Some only wear glasses to drive but for nothing else. One of the guys told me his optometrist pescribed him glasses even though he wasnt even considered myopic because he probably gets a comission or he owns the place and pescribes glasses to anyone not 20/20 or plano. Needless to say he didnt even bother wearing glasses, it didnt seem to make a difference, he was only a -.5 and 20/25 instead of 20/20 so of course he found glasses a silly thing. They "broke" oneday and his parents tossed them out and agreed that the glasses was a complete waste of money. "If you have 1.5 pseudo, you don't have to do anything. It will correct itself" stop doing close work or use a plus lense for close work. You need to give your eyes a chance to rest so they can relax their pseudomyopia. "And you are right, structural myopia cannot be improved by not wearing glases, or by wearing them less, or by not wearing them at all. This has been proven." Even some natural vision improvement books indirectly hint this, they say stuff like different people achieve different levels of improvement. Its agreed that almost everyone has at least half diopter pseudomyopia and a fair number have a diopter to a diopter and a half. I have read into this and cycoplegic refractions and the reports show most people being a little less cycoplegic than manifast. I guess this is how they get the 90% figure for vision improvement. I read the diary of one lady who improved by 1.25 diopters and said her friends all improved by at least half diopter too. One thing is for certain, you can slow or stop your eyes from getting worse by using them right. "There is a psychological adaptation that myopes can make by going without their spec for a few days that makes them feel their eyes have improved, but every time you put them in the chair they still have the same unaided acuity and the same refraction." My brothers vision improved by half diopter in each eye over the last 3 years. I wouldnt be supprised if he improves more once he finishes college and stops doing so much close work. He only wears glasses to drive. He may even be 100% pseudomyopia due to close work. Either way, his vision now is 20/60 and probably wont be getting any worse. "some of which has actually harmed people" maybe because they went without their glasses when they should be wearing them. Like for driving, you MUST wear full power glasses. For crossing the street, if you have more than a little myopia, you should wear glasses strong enough to give you at least 20/100 vision to see well enough to get about. My vision improvement book talks about T-glasses where the optometrist will correct you only to 20/40 so you have room to improve your vision. The patients then come a few months later with 20/20 or 20/25 vision and get stepped down again in their pescription! "It seems that Steve was nearsighted from age 13. He was "down" to -2.75 diopters (about 20/200), and now is passing the 20/40 line. I think that Steve was very lucky, and clearing from that level is very difficult. It took him about four months to do it." How much of my -4.5 and -5 pescription can I clear? I already dont use glasses to read and I undercorrect myself with -3.25 glasses around the house and -4.25(T-glasses) when I go out which give me 20/40 vision(my BCVA is only one line better) "there is at least one contributor on this s.m.v. who really believes in and promotes the concept of avoiding the "evil minus" It cant hurt. Its best to start when you first start getting myopic. Dont touch the minus and use plus whenever doing close work. If the eyes still get worse, then work on slowing down the progression of myopia. " don't drive (or ride your bike) without your minus lenses..." If one is a low myope, he can do most things without glasses. If one meets the DMVD(?) by being 20/40 UCVA, he has no obligations for glasses in 99% of the cases(except to pilot a plane) Others can undercorrect themselves to resolve pseudomyopia. A useful way is get a cycoplegic refraction using a strong cycoplegia agent then wear glasses based on your cycoplegic numbers because thats your REAL myopia. If you cant see 20/40 with your cycoplegic power glasses, then wear full power only for stuff like driving or watching movies and stick to your cycoplegic pescription power glasses. > if someone was only a -1.5, glasses would make no difference and just > result in eyestrain for close work even if the eyes dont get worse. Where did you hear that -1.5 causes eyestrain at near? While it is possible, it is certainly not true in all cases, not even in MOST cases. Most 1.50 wearers have no eyestrain when reading with -1.50, in fact a lot of exophorics actually get eyestrain if they DON'T wear them. The only explanation is maybe they didnt even > know they had a vision problem exactly correct, although some of them didn't get glasses because of quack advice to avoid the minus. > Well, its been said that glasses will help your myopia progress faster > and longer. It's also been said that rubbing a penny on a wart and burying it on a full moon will cure the wart... I find it strange that my friends who dont wear > glasses never developed much myopia while those who did rapidly got > worse. Here we go agin with post hoc propter hoc. It isn't strange at all to me that your friends who never developed much myopia didn't need glasses as much as those who rapidly did so. What could be more obvious??? > "some of which has actually harmed people" > > maybe because they went without their glasses when they should be > wearing them. Like for driving, you MUST wear full power glasses. Exactly correct. Unfortunately some charlatans believe you should drive with only the minimum legal required vision. There's where some of the harm comes. The other is from causing amblyopia in some children. > If one is a low myope, he can do most things without glasses. If one > meets the DMVD(?) by being 20/40 UCVA, he has no obligations for > glasses in 99% of the cases Oops. Here I gave you credit for being smart enough to see through that idiotic fallacy. Oh well, another mistake in judgement... w.stacy, o.d. Dear Acema, You will have to strike a "balance" on some of these OD statements. Stacy> "some of which has actually harmed people" William will make this statement, while totally ignoring the stair-case myopia that develops when you begin wearing an over-prescribed minus -- all the time, and pseudo-myopia is converted into "regular myopia" by that process. You can see the same thing in the proven behavior of the primate eye when you: 1. Place a minus lens on it, or 2. Place the test group in a more-confined visual environment. I am certain that William will come up with some "logic" to deny this proven behavior of a population of natural eyes. At some point -- you should run these experiments yourself -- and draw your own conclusion. But equally, I do acknowledge that true-prevention is difficult, and like Steve or Dr. Colgate, you are left with no choice but to choose to do it yourself -- if that is your scientific judgment in this matter. I do restrict my statement to ONLY the prevention of pseud-myopia, i.e., eye-chart between 20/40 to 20/70, (before you convert it into "regular" myopia.) In fact I agree with William, that once you cross that threshold by wearing that wretched minus lens all the time, there is no real prospect of getting out of it. (Or William's famous "axial" myopia.) As always, enjoy our pleasant discussions on how to avoid converting your pseud-myopia into stair-case myopia. Best, Otis >At some point -- you should run >these experiments yourself -- and >draw your own conclusion. Otis Brown doubles as a macaque for this sort of testing. >But equally, I do acknowledge that >true-prevention is difficult, ... and has proved ineffective in numerous studies... >and >like Steve or Dr. Colgate, you [quoted text clipped - 5 lines] >I do restrict my statement to >ONLY the prevention of pseud-myopia, The piper may be slowly changing his tune here, folks! >i.e., eye-chart between 20/40 to 20/70, >(before you convert it into "regular" >myopia.) Ooops. Relapse. No proof that this occurs, Otis ... and you should know this by now. >In fact I agree with >William, that once you cross that >threshold by wearing that wretched >minus Oh, that damnable minus lens. The scourge of humanity. If only we'd found the stockpiles of minus lenses when we invaded Iraq. That would have shown 'em. >lens all the time, there >is no real prospect of getting [quoted text clipped - 5 lines] >converting your pseud-myopia >into stair-case myopia. The only proven way is ignoring Otis. SignatureLive simply so that others may simply live > totally ignoring the stair-case myopia > that develops when you begin wearing an > over-prescribed minus -- all the time, and > pseudo-myopia is converted into > "regular myopia" by that process. You must disregard all the human research to believe this. Why do you propagate misinformation? -MT Dear Acema, >From long conversations with prevention-minded ODs, I found out that the second-opinion is PREVENTION with a strong plus -- used on the threshold -- and used by the person himself. A great many people lack the fortitud to do this -- and if offered it -- they will turn it down cold. But then they must "suffer" the consequences. Just recently, Steve worked his way out of nearsighedness. (I am only wlling to "claim" from 20/70 to 20/40 or better.) You will find his commentary on my site (left hand page) as Steve to 20/30. Makes an "interesting" read. www.myopiafree.com It seems that Steve was nearsighted from age 13. He was "down" to -2.75 diopters (about 20/200), and now is passing the 20/40 line. I think that Steve was very lucky, and clearing from that level is very difficult. It took him about four months to do it. As always, enjoy our pleasant analytical discussion about the dynamic behavior of the fundamental eye. Best, Otis (questions) As you can see, there is at least one contributor on this s.m.v. who really believes in and promotes the concept of avoiding the "evil minus". He has caused harm on occasion, but you are smart enough to not be harmed by it, so caveat emptor and don't drive (or ride your bike) without your minus lenses... w.stacy, o.d. > In its initial phase, your all your myopia > (say -1.0 diopters) could have been [quoted text clipped - 3 lines] > > Just one man's opinion. Of course, if it were true, all hyperopes would become myopes. I haven't seen that happen. Perhaps you have. -MT "Of course, if it were true, all hyperopes would become myopes." http://www.i-see.org/allen_hyp.html very good article on emmetropization. Its normal for babies and young children to be hyperopic. If they have high hyperopia, give them the minimum needed for clear distance vision and let them accomodate the rest and go thru emmetropization. Keep bumping down their pescription to encourage emmetropization. If enough of their hyperopia has been emmetropized, they no longer need correction till they start getting presbyopia. "how does pseudomyopia convert to "real" myopia? does the eyeball get longer? does the cornea change its curvature? does the index of refraction of the ocular media change? does the lens change its curvature within the eye (without the action of the ciliary muscle which would then be classified as pseudomyopia)? do you understand physiological optics?" most often from axial myopia. This means the eyeball grows longer when overstimulated with close work then it undergoes a response of enlongating to faciliate near seeing. "Where did you hear that -1.5 causes eyestrain at near?" when wearing minus glasses when you shouldnt, dont need to. If someone is only a -1.5 he only needs glasses for distance seeing, NOT near! "exactly correct, although some of them didn't get glasses because of quack advice to avoid the minus." as long as they can see and function fine without glasses, then theres no need. Its common for low myopes to forgo glasses like my brother. Many dont even believe in avoiding the minus for the sake of improving their eyes, they avoid it because glasses are an inconvinence. The lense gets smeared and dusty alot, glasses are a presence and weight on the face and some people dont like the way they look with glasses. "Here we go agin with post hoc propter hoc. It isn't strange at all to me that your friends who never developed much myopia didn't need glasses as much as those who rapidly did so. What could be more obvious???" But if those people who wore glasses developed more myopia, it explains it. Most everyone starts out with slight myopia. Some chose not to bother with glasses, others do and need stronger and stronger glasses. Coincidence or what? "Exactly correct. Unfortunately some charlatans believe you should drive with only the minimum legal required vision. There's where some of the harm comes. The other is from causing amblyopia in some children." If driving with the minimum 20/40 vision was harmful then the requirement should be 20/25 or something. This of course would leave more people out from driving but it would support your statement that 20/40 is not good enough to safely drive. By your statement, I probably shouldnt drive because my BCVA isnt good enough, especially not at night. I dont drive but I have other excuses besides my vision. As for amblyopia, this is often caused by anisometropia, one eye being much more dormant than the other, seeing much better than the other. Use the patch to exercise the weaker eye! "the stair-case myopia that develops when you begin wearing an over-prescribed minus -- all the time, and pseudo-myopia is converted into "regular myopia" by that process." This seems to explain perfectly how me and my friends became more and more myopic and each time our glasses got bumped up, our eyes would rapidly get worse then slow down due to the now too weak glasses. One time I put off getting new glasses for 2 years and my vision didnt get any worse than it did after one year then as soon as I got the new glasses in 3 months it got another half diopter worse then stopped. "You can see the same thing in the proven behavior of the primate eye when you: 1. Place a minus lens on it, or 2. Place the test group in a more-confined visual environment." exactly! read this on the net, its been proven! "Oh, that damnable minus lens. The scourge of humanity. If only we'd found the stockpiles of minus lenses when we invaded Iraq. That would have shown 'em." LOL! In its defense, the minus lense can be used for stuff like driving, watching movies, reading the chalkboard from back of class or basically using it for distance seeing. DO however go without glasses for near seeing and if your a low myope, forgo wearing glasses around the house and in familiar surroundings. > most often from axial myopia. This means the eyeball grows longer when > overstimulated with close work then it undergoes a response of > enlongating to faciliate near seeing. It may be so. But what human study shows we can manipulate it by wearing or not wearing lenses after the age of 10? > when wearing minus glasses when you shouldnt, dont need to. If someone > is only a -1.5 he only needs glasses for distance seeing, NOT near! Maybe, maybe not. Some have convergence issues and are more comfortable with them than without. Less "eyestrain," they say, whatever that is. Accommodating is not a "strain" for normal young people. They have an overabundance of it. > But if those people who wore glasses developed more myopia, it explains > it. Most everyone starts out with slight myopia. Some chose not to > bother with glasses, others do and need stronger and stronger glasses. > Coincidence or what? How do you know those with glasses got more myopic? In controlled studies, the two groups don't really differ. If you find a study that says otherwise, please clue us in. > This seems to explain perfectly how me and my friends became more and > more myopic and each time our glasses got bumped up, our eyes would > rapidly get worse then slow down due to the now too weak glasses. Yes but I'm not so sure you used sound sampling principles when choosing your experimental and control groups. I've seen studies where the participants were chosen much more carefully and those studies say it doesn't make much difference whether you wear glasses or not. Some of them even indicate it's better to leave them on full time, but not enough to make any rigid recommendations. -MT "It may be so. But what human study shows we can manipulate it by wearing or not wearing lenses after the age of 10?" http://www.i-see.org/eyeglasses_harmful/chap2.html http://members.aol.com/myopiaprev/ http://members.aol.com/myopiaprev/prv1.htm "Maybe, maybe not. Some have convergence issues and are more comfortable with them than without. Less "eyestrain," they say, whatever that is. Accommodating is not a "strain" for normal young people. They have an overabundance of it." Do not wear full-strength prescription minus-lens glasses (the type given to nearsighted people) when doing near work. These glasses make close things appear even closer -- wearing them for close work is the worst thing you can do. Normal and mildly nearsighted people can read fine without glasses. Need glasses to read? Use weaker lenses for nearwork If you are already quite nearsighted and need glasses to read, then those glasses you use for reading should be 1.50 to 2.00 diopters weaker than your full distance prescription. Why? Your full-strength glasses are made for distance vision, not for close work! The goal for a weaker prescription is the same as with reading glasses: things at your normal reading distance should be slightly blurry. Example: If your distance prescription is -4.50 diopters, you'd want about -2.50 to -3.00 D for reading. ****This is what I do! My real pescription is -4.5 to -5 but I wear -3.25 glasses. My undercorrection is about -1.5 diopters which reduces me from 20/30 to 20/80 but its great for near and intermediate. I often just read without glasses alltogether at a distance slightly blurry to me to relax my ciliary muscles**** "I've seen studies where the participants were chosen much more carefully and those studies say it doesn't make much difference whether you wear glasses or not." and ive seen the opposite. Besides theres no harm using the plus lense as ive said. If it doesnt work then youll be more myopic. Not using the plus lense will make you more myopic anyway, might as well try! "The 20/40 rule is there because they have to draw the line somewhere, just like the 1/8" rule. It is NOT a suggestion! I'm pretty sure you are smart enough to understand what I'm saying." I understand but the thing is most people will not care either way. Theres millions of people driving with outdated glasses pescriptions, some not even seeing 20/40! Theres tons of people whos vision got ruined with lasik but still drive. Heck theres many people who drive when they arent feeling well and this affects their concentration. Many low myopes who meet the DMVD dont bother even getting glasses and have never worn or will ever wear glasses, period. Dont worry about me, I dont drive. I can meet the 20/40 requirement but I wont make a very safe driver vs. someone who can see 20/20. I also have several other reasons for not wanting to drive. Theres also other reasons for high vision requirements, some jobs and activities require very good vision. In most cases its important to see the best one can but if someone is at home, its perfectly acceptable to wear weaker glasses around the house. Its also acceptable for doing lots of near work, in fact many people DONT see very well with their distance glasses for near work. With regard to Ace's inquiries and discussion: I have considerable empathy since, at his age, I was going through much the same quandary as he is. This was my theory, and it made considerable sense. http://home.att.net/~muffkat/accomodation/ It still does. It makes a whole lot more sense than the axial-length-changing theory. So maybe that is good for chickens. I could not dispute that. I guess there are plenty of similar and identical theories, but they seem presently to be in eclipse. Listen! Eyeballs are round. If they got long and skinny, how could eyes be "rolled"? Probably they grow, in spherical diameter, to fit the sockets they are in, as those grow. Are there any studies of whale eyes out there? Most of the you guys here seem to be on the same bandwagon, except Otis, who seems to be on his own. Well, guys, we still got to explain why it is that populations who go studious invariably go myopic. So, perhaps I am wrong about everything. I am sure you will tell me, and send me over in the corner with Otis (where I do not think I actually belong). (Send me over to the same corner as Ace.) -- Dicky With regard to Ace's inquiries and discussion: I have considerable empathy since, at his age, I was going through much the same quandary as he is. This was my theory, and it made considerable sense. http://home.att.net/~muffkat/Accomodation/ It still does. It makes a whole lot more sense than the axial-length-changing theory. So maybe that is good for chickens. I could not dispute that. I guess there are plenty of similar and identical theories, but they seem presently to be in eclipse. Listen! Eyeballs are round. If they got long and skinny, how could eyes be "rolled"? Probably they grow, in spherical diameter, to fit the sockets they are in, as those grow. Are there any studies of whale eyes out there? Most of the you guys here seem to be on the same bandwagon, except Otis, who seems to be on his own. Well, guys, we still got to explain why it is that populations who go studious invariably go myopic. So, perhaps I am wrong about everything. I am sure you will tell me, and send me over in the corner with Otis (where I do not think I actually belong). (Send me over to the same corner as Ace.) -- Dicky >Well, guys, we still got to explain why it is that populations >who go studious invariably go myopic. > > It's emmetropization gone haywire to the near point. Everyone in eyecare knows that, regardless of what Beavis claims. w.stacy, o.d. > >Well, guys, we still got to explain why it is that populations > >who go studious invariably go myopic. > It's emmetropization gone haywire to the near point. What a great theory. Maybe some one will write a dissertation about that. Heck, maybe it will be Ace. > Everyone in eyecare knows that, regardless of what Beavis claims. It is good to know that there is a simple answer. Which one is "Beavis"? -- Dicky >> >Well, guys, we still got to explain why it is that populations >> >who go studious invariably go myopic. [quoted text clipped - 9 lines] > >It is good to know that there is a simple answer. Which one is "Beavis"? Blonde hair. "Metallica" shirt (NOT the brunette in the AC/DC shirt). HTH, Neil SignatureLive simply so that others may simply live > This was my theory, and it made considerable sense. > http://home.att.net/~muffkat/Accomodation/ > > It still does. It makes a whole lot more sense than > the axial-length-changing theory. Then, you and Otis belong in the same room together where you can share your beliefs without provoking arguments with people who have more knoweldge of the subject. Clinging to a belief in the face of evidence to the contrary is irrational. DrG > > This was my theory, and it made considerable sense. > > http://home.att.net/~muffkat/Accomodation/ [quoted text clipped - 6 lines] > knoweldge of the subject. Clinging to a belief in the face of evidence > to the contrary is irrational. I know this is a bit hard to understand, but Otis and I are not exactly saying the same thing (so far as I can understand what Otis may be saying). Otis proposes a therapy, whereas I attempt to discuss a possible mechanism. I doubt if myopia is reversible. Pseudomyopia seems a very fuzzy concept. I consider that myopic progression in some cases may be preventable in spite that there may not be adequate evidence that it has yet been done. Maybe those little white flecks which characterize you make it difficult to see what you may be trying to read correctly? -- Dicky > I know this is a bit hard to understand, but Otis and I are not exactly > saying the same thing (so far as I can understand what Otis may be saying). [quoted text clipped - 8 lines] > Maybe those little white flecks which characterize you make it difficult to > see what you may be trying to read correctly? I think I understand you perfectly well. In proposing a theory, Otis has expressed his belief in the same causal mechanism. Pseudomyopia doesn't seem like a "fuzzy concept" to me. I know that myopic progression can be arrested. This has already been shown with atropine, a non-selective anti-muscarinic agent, and to a lesser extent with the selective anti-muscarinic agent, pirenzepine. This method works without plus lenses. There is also an accumulating body of work on the effect of eye shape factor on the progression of refractive errors. An important point is that the eye seems to respond quite strongly to defocus -- and not to accommodation. DrG > [ ... ] > I know that myopic progression can be arrested. This has already been > shown with atropine, a non-selective anti-muscarinic agent, and to a > lesser extent with the selective anti-muscarinic agent, pirenzepine. I hope for a more convenient way. > This method works without plus lenses. "Plus lens" is a pretty crude descriptor. I have not used that term. > There is also an accumulating body of work on the effect of eye > shape factor on the progression of refractive errors. No doubt longer eyes are more apt to become myopic. I express doubt that elongation is an adaptive mechanism, and that longer eyes are not proportionally fatter in the interest of being rounder, notwithstanding chickens. > An important point is that the eye seems to respond > quite strongly to defocus -- and not to accommodation. I understand that they eye responds to defocus by trying to focus, which is to say, by accommodating. Otherwise I can't guess what you are trying to get at. Is it about chickens? There does seem a possibility that accommodating close objects may lead to myopic changes over a period of time, particularly in adolescents. -- Dicky > I understand that they eye responds to defocus by trying to focus, > which is to say, by accommodating. Otherwise I can't guess what [quoted text clipped - 5 lines] > may lead to myopic changes over a period of time, particularly in > adolescents. The eye responds to defocus by elongating (or getting shorter in the case of chicks), even when accommodation is prevented. Don't take my word for it, though. Do a literature search. DrG "Dick Adams" <bad.addr@nonexist.com> > There does seem a possibility that accommodating close objects > may lead to myopic changes over a period of time, particularly in > adolescents. As shown by all those uncorrected adolescent hyperopes who don't get nearsighted? -MT >"Dick Adams" <bad.addr@nonexist.com> > [quoted text clipped - 4 lines] >As shown by all those uncorrected adolescent hyperopes who don't get >nearsighted? Oh, would that it were so.... Neil Chairman Emeritus Hapless Hyperopes of America SignatureLive simply so that others may simply live > "Dick Adams" <bad.addr@nonexist.com> > [quoted text clipped - 4 lines] > As shown by all those uncorrected adolescent hyperopes who don't get > nearsighted? Some don't get nearsighted. Probably the ones with small eyeballs are more likely not to. That is why I carefully used the word "may". That inclusion expresses that I am not saying "all", or not definitely "any". But, some do, you know, and more likely the nerds than the jocks. I think that some of you folks need to do a review of General Semantics. "A" may be "B", does not imply that all that all "B" is "A". By the way, while we are on the subject, "B" not different than "A" is without meaning if both "B" and "A" are a total blur. -- Dicky > "Dick Adams" <bad.a...@nonexist.com> Dicky> > There does seem a possibility that accommodating close objects may lead to myopic changes over a period of time, particularly in adolescents. Dear Dick Adams, Right you are!!! The Oakley-Young study proved that the full-corrected child went "down" at a rate of -1/2 diopter per years (2 diopters over 4 years) while the "plus" group did not go "down" at all. (Please remember this was a "blind" study so it was very difficult to "control" this child in his use of the plut.) Ths indication is that more "forceful" use of the plus COULD HAVE resulted in the person's CLEARING of his distant vision if he used a STRONGER plus at the threshold. Of course this result has already been achieved by pilots who "woke up" the SCIENTIFIC (not medical) necessity of it. Best, Otis >Some don't get nearsighted. If you wanted to be accurate you'd say "the majority don't get nearsighted." But that sorta shoots your theory in the foot. So does this one: Investigative Ophthalmology & Visual Science, Vol 40, 1050-1060 K Zadnik, DO Mutti, HS Kim, LA Jones, PH Qiu and ML Moeschberger Tonic accommodation, age, and refractive error in children CONCLUSIONS: This is the first study to document an association between age and tonic accommodation. The known association between tonic accommodation and refractive error was confirmed and it was shown that an ocular component, Gullstrand lens power, also contributed to the tonic accommodation level. There does not seem to be an increased risk of onset of juvenile myopia associated with tonic accommodation. > Probably the ones with small > eyeballs are more likely not to. I'd like to know more about the sampling methods you used to determine that. > I think that some of you folks need to > do a review of General Semantics. > "A" may be "B", does not imply that all "B" is "A". So all myopia is caused by accommodation? By the time most people start developing myopia, the diameter and circumference have reached 95-100% of adult size. Then the axial changes associated with juvenile myopia are easy to measure with ultrasound, so it's no mystery. This is just the first reference I found.. http://www.optometrists.asn.au/ceo/backissues/vol79/no4/1083 > By the way, while we are on the subject, > "B" not different than "A" is without meaning > if both "B" and "A" are a total blur. That sounds like your refractionist having a bad day. -MT "Mike Tyner" sez to Dicky: > If you wanted to be accurate you'd say "the majority don't get nearsighted." That would be taking a bigger chance of being inaccurate, as I do not have the precise numbers at hand. > But that sorta shoots your theory in the foot. Exactly what theory are you ascribing to me? > So does this one: > Investigative Ophthalmology & Visual Science, Vol 40, 1050-1060 > K Zadnik, DO Mutti, HS Kim, LA Jones, PH Qiu and ML Moeschberger [quoted text clipped - 6 lines] > accommodation level. There does not seem to be an increased risk of onset of > juvenile myopia associated with tonic accommodation. That must be your writing, not the authors'. What exactly do you take to be the meaning of *tonic accommodation*?? > > Probably the ones with small eyeballs are more likely not to (become >> myopic). > I'd like to know more about the sampling methods you used to > determine that. Oh, one is free to speculate without making a determination. That was hardly a categorical statement. But I will stick by it. > > I think that some of you folks need to do a review of > > General Semantics. > > "A" may be "B", does not imply that all "B" is "A". > So all myopia is caused by accommodation? That does not follow from the above Boolean axiom. You are again demonstrating the art of *non-sequitur* Accommodation is the process of obtaining a sharp image of a viewed object on the retina. To say that accommodation causes myopia is like saying that driving cars causes automobile accidents. > By the time most people start developing myopia, the diameter and > circumference have reached 95-100% of adult size. Then the axial changes > associated with juvenile myopia are easy to measure with ultrasound, so it's > no mystery. This is just the first reference I found.. > http://www.optometrists.asn.au/ceo/backissues/vol79/no4/1083 That is an abstract which concludes: "This result shows an association between axial elongation of the globe and optic disc ovalness, in addition to the previously described temporal myopic crescent. Therefore, in myopic subjects, a vertically oval disc may be associated with a myopic refraction rather than glaucoma." What does that have to do with this subject at hand? I would like to find the ultrasound data to which you allude. -- Dicky "Mike Tyner" sez to Dicky: >> If you wanted to be accurate you'd say "the majority don't get >> nearsighted." >That would be taking a bigger chance of being inaccurate, as I do not >have the precise numbers at hand. Nor do I, but after 20 years of measuring them I can tell you that the majority of hyperopes do not get nearsighted. Which they should, if accommodation stimulated myopia. >> But that sorta shoots your theory in the foot. > Exactly what theory are you ascribing to me? The one at http://home.att.net/~muffkat/Accomodation/ . That was yours, right? >> accommodation level. There does not seem to be an increased risk of onset >> of >> juvenile myopia associated with tonic accommodation. > That must be your writing, not the authors'. What exactly do you take to > be > the meaning of *tonic accommodation*?? No, I didn't write that. I cut and pasted from the abstract. I believe you know what accommodation is. You should also know that the ciliary muscles are seldom completely at rest, even during sleep. "Tonic" accommodation is accommodation that remains when the stimulus is at infinity and the eyes are "at rest." Roughly it's the difference between a good cycloplegic refraction and a refraction without cycloplegic. >> Probably the ones with small eyeballs are more likely not to (become >> myopic). >Oh, one is free to speculate without making a determination. That was >hardly a categorical statement. But I will stick by it. I believe Asian eyes are on average a little smaller than caucasian. Yet they have 2-3 times more myopia. >> > I think that some of you folks need to do a review of >> > |
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