Medical Forum / General / Vision / March 2006
How large a zone can orthoK go up to? 7mm? larger?
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acemanvx@yahoo.com - 08 Mar 2006 23:16 GMT Due to my huge pupils, I will want the largest zone possible. I know 6mm is standard but theres also 5.5mm and 5mm as well as larger. I have seen 7mm and heard of even larger! I googled it and orthoK is indeed available in 7mm. Not sure if larger but 7mm is not bad as my pupil probably wont get over 7mm except in near total darkness. I am willing to accept mild halos and starbursts or rather, a mild increase over what I have. I use my vision in the day much more than night and I dont drive anyway so it wouldnt matter. If worse for worse comes, orthoK is reversable and I can stop orthoK then resume it anytime.
p.clarkii@gmail.com - 09 Mar 2006 00:29 GMT your pupils wouldn't be so large if you quit eating mushrooms. now go discover girls or something-- quit fixating on vision
RT - 09 Mar 2006 01:17 GMT > your pupils wouldn't be so large if you quit eating mushrooms. > now go discover girls or something-- quit fixating on vision Kim - Plus size model's Dreambook ... Saturday, September 14th 2002 - 06:12:40 AM Name: ace. E-mail address: acemanvx@yahoo.com. Comments: I enjoyed looking at the photos
:) got any more photos? ... books.dreambook.com/kimhawke/kimhawke.html - 9k - Supplemental Result -
 Signature ~RT
Dr. Leukoma - 09 Mar 2006 03:28 GMT Ace,
In my opinion, 7 mm is out of the question for your prescription. The amount of correction is inversely proportional to the diameter of the treatment zone. Look up Munnerlyn's formula for the exact relationship. One generally has only 50 microns of tissue to play with, so figure out the maximum depth is 50 microns, the diameter is 7 mm. How much correction in diopters can result?
Drg
CatmanX - 09 Mar 2006 10:44 GMT Making a 7mm optic does not equate to the optic zone created on the cornea.
Anyway, no-one would touch a douche like you anyway Nancy.
dr grant
Dr. Leukoma - 09 Mar 2006 12:55 GMT This is true. But, since you are the "expert," exactly what probability do you give to getting that accomplished, pretending that the k's and eccentricity are "average"?
DrG
acemanvx@yahoo.com - 10 Mar 2006 00:41 GMT "One generally has only 50 microns of tissue to play with, so figure out the maximum depth is 50 microns, the diameter is 7 mm. How much correction in diopters can result?"
OrthoK can only flatten 1/3 to 1/2 of that. If you have 50-60 microns to play with, figure about 25 microns maximum to play with. With 6mm orthoK, thats 6 microns per diopter so 4 diopter improvement is about the limit. with 7mm zone, its 8 microns per diopter so the limit becomes 3 diopters.
"In my opinion, 7 mm is out of the question for your prescription."
I wear -3.25 glasses most of the time.
"Making a 7mm optic does not equate to the optic zone created on the cornea."
itll be about 6.75 mm for a 3 diopter correction. I will see if I can get 7.5mm or even 8mm zone orthoK.
Dr. Leukoma - 10 Mar 2006 02:25 GMT OK, Ace. You win. Nobody can tell you anything.
So, run along and get OK and report back to us.
The OK nomograms are derived from Munnerlyn's formula as any OK expert will tell you. Of course the amount of tissue displaced will vary with the thickness of the epithelium, and is not the same for everybody.
DrG
CatmanX - 10 Mar 2006 11:56 GMT Actually most are derived from Jessen's formula, with the exception of BE, which take a different tack.
However, you are correct in thinking that Nancy is a dickhead. She really is. She does not listen, she thinks you are an OK expert, when you have publically ridiculed OK (as is your right) and then tells you how to prescribe RGP lenses.
I agree with you Lou, Nancy is one sick puppy.
Happy refracting brother in lenses.
dr grant
Dr. Leukoma - 10 Mar 2006 13:58 GMT > Actually most are derived from Jessen's formula, with the exception of > BE, which take a different tack. Virtually all of the OK experts who publish make reference to Munnerlyn's formula. For those who don't know, the Jessen to whom Grant refers is George Jessen, the co-founder of Wesley-Jessen, and the widely acknowledged founder of modern OK, who was still practicing and lecturing in Chicago during the time I went to school there.
> However, you are correct in thinking that Nancy is a dickhead. She > really is. She does not listen, she thinks you are an OK expert, when > you have publically ridiculed OK (as is your right) and then tells you > how to prescribe RGP lenses. I have never publicly ridiculed OK, Grant. We have calmly and rationally discussed different sides of the OK issue. Although I am certified to do OK, I don't do much of it. For me, and for now, overnight OK is not on the table. For me, OK is still a means by which patients can extend the refractive effects after their lenses are removed for the evening, or for sports and other activities.
DrG
CatmanX - 10 Mar 2006 19:31 GMT The guys who design OK lenses all use Jessens formula, which is prescribing a lens that is 4D flatter than flat K. The only exception to this is the BE series, which chooses base curve according the the required change in script. Munnerlyn's formula is only used in publications to discuss corneal curve changes, not in calculation and design of lenses.\\
dr grant
Dr. Leukoma - 10 Mar 2006 20:48 GMT > The guys who design OK lenses all use Jessens formula, which is > prescribing a lens that is 4D flatter than flat K. The only exception [quoted text clipped - 4 lines] > > dr grant Here we go. Of course, that statement didn't sound right, and so I called up a lens designer. He calculates the base curve from the patients RX and the corneal curvature. He indicated that the method you describe is somewhat outdated.
DrG
CatmanX - 11 Mar 2006 04:09 GMT Actually, he just used Jessen's formula. Add the script to the flat K (in D) and add an extra 0.50. This is the indicated base curve for your lens. That is Jessen's formula. Your lens designer used it, CRT uses it, Tabb uses it, Euclid uses it, R&R use it. This is why with all these designs, you get a +0.50 overrefraction over your trial lens.
grant
Dr. Leukoma - 11 Mar 2006 04:26 GMT > Actually, he just used Jessen's formula. Add the script to the flat K > (in D) and add an extra 0.50. This is the indicated base curve for your [quoted text clipped - 3 lines] > > grant Sorry, I was confused. In the previous post, you said 4 diopters flatter than K. If you said just add 0.50 diopters of minus to the script, I would have understood. In fact, I would have understood better if you had said 0.75 diopters added to the script.
DrG
CatmanX - 11 Mar 2006 04:57 GMT Sorry, at 5.00am the formula didn't come straight away.
grant
Dr. Leukoma - 11 Mar 2006 04:35 GMT By the way, for those who don't understand, Grant is making the point that shoots for an over-correction of 0.50 to 0.75 diopters in orthokeratology to allow for the normal regression during the day.
So, in essence you wake up a little farsighted and go to bed a little nearsighted.
DrG
CatmanX - 11 Mar 2006 05:00 GMT Sorry, I missed your point here. You were trying to score one were you not?
It has always been standard practice to overcorrect slightly. The benefit is you get 6/6 acuity all day. I don't have a problem with it, neither do my patients.
grant
Dr. Leukoma - 11 Mar 2006 12:20 GMT > Sorry, I missed your point here. You were trying to score one were you > not? I believe that I stated "for the benefit of those who don't understand." There are many non-professionals here.
> It has always been standard practice to overcorrect slightly. The > benefit is you get 6/6 acuity all day. I don't have a problem with it, > neither do my patients. I would have a problem with it for myself.
Cheers.
DrG
CatmanX - 11 Mar 2006 13:32 GMT Firstly, you don't know you'd have a problem if you don't try it. Second, if you don't like it, don't do it. It really is simple. You really try to spoil for a fight every time you post. You really should lighten up a little Greg.
dr grant
acemanvx@yahoo.com - 11 Mar 2006 14:03 GMT Dont mind Grant, he is rude and childish to everyone. I do my best to treat everyone with respect. I will be making an appointment with Dr. Maller, the orthoK expert soon and ask him lots of questions and get lots of testing. If he says orthoK isnt for me then be it. If he says I have a reasonable chance of it working out, ill be going for it!
CatmanX - 11 Mar 2006 20:56 GMT That's really good. I am sure you will teach him all he needs to know about contacts and evil myopia.
dr grant
acemanvx@yahoo.com - 13 Mar 2006 01:01 GMT He will be the teacher. I ask questions and listen to his answers. I still want to know how large orthoK can go to. It appears that no one here knows
CatmanX - 13 Mar 2006 01:36 GMT I can already tell you that it won't work. You won't listen, so I won't tell you.
Suffice to say, 7.0mm zones are rarely made and the effect is that they have little if any effect when you are trying to correct over 3D of myopia.
I now suppose we will have to put up with you lecturing us about OK for the next year of 2 like you did with Lasik. You never went for that either. You won't see Ken Maller and you will still tell us how much you know about OK.
Pity my 14 years prescribing and selling OK lenses isn't good enough for you, but we all know you know more than any OD does.
Time to go away Nancy.
dr grant
acemanvx@yahoo.com - 14 Mar 2006 01:32 GMT "Suffice to say, 7.0mm zones are rarely made and the effect is that they have little if any effect when you are trying to correct over 3D of myopia."
a -3d correction is definately enough. I wear -3.25 glasses and have been exclusivately for the last 3 weeks. I dont like my full power glasses, they give me headaches, make things blurry from near and strain my eyes and make me feel dizzy. I think my cylindar and anisometropia is also responsable for this. My script is:
left eye: -4.5 sphere, -.75 cylindar(140 axis) correctable to 20/30 right eye: -3.5 sphere, -1.5 cylindar(55 axis) correctable to 20/40
OrthoK should take care of all my cylindar in left eye and most or all in right eye. OrthoK can also take care of anisometropia by balancing both eyes so they are no more than half diopter difference.
"I now suppose we will have to put up with you lecturing us about OK for the next year of 2 like you did with Lasik."
I will lecture people on anything I know about.
"You won't see Ken Maller and you will still tell us how much you know about OK."
I plan on making an appointment with Maller next week. He will teach me all I need to know. If he says orthoK is for me or if its not for me, I will trust his judgement. If he doesnt feel I will get anywhere with orthoK, ill put it off and save my money and just deal with undercorrected glasses and my crappy distance vision. if he says orthoK is likley to work, I am going for it!
"Pity my 14 years prescribing and selling OK lenses isn't good enough for you"
You didnt say so sir! Tell me your experience. How much cylindar can orthoK on average reduce? How much myopia on average for 7mm orthoK zone? Is there 7.5mm or even 8mm zones?
p.clarkii@gmail.com - 14 Mar 2006 01:55 GMT i bet you don't have many friends do you ace/nancy?
CatmanX - 14 Mar 2006 08:37 GMT > OrthoK should take care of all my cylindar in left eye and most or all > in right eye. OrthoK can also take care of anisometropia by balancing > both eyes so they are no more than half diopter difference.
You are talking about correcting one eye by -2D and the other by -3D are you? I hope your e values are appropriate.
> I will lecture people on anything I know about.
Yes, but this is a topic (another one) that you know nothing about.
> I plan on making an appointment with Maller next week. He will teach me > all I need to know.
You will bore him stupid with your demands. H
> You didnt say so sir! Tell me your experience. How much cylindar can > orthoK on average reduce? How much myopia on average for 7mm orthoK > zone? Is there 7.5mm or even 8mm zones?
I have repeatedly written of having prescribed OK for many years. I have disagreed with many, such as Greg Gemoules about OK, when he has never practiced it. You have once again failed to listen, like with myopia prevention, a topic of which I am also somewhat an expert.
I know of no OK designs that go to a 7mm OZ. It is not practical from a fluid hydraulics perspective. The largest OZ I know of is 6.5mm and this is only ordered after suitable fitting with a 6mm lens is confirmed.
Your astigmatism is not going to be corrected by OK. Oblique cyls do not reduce and in many cases will get worse with OK. You have not done your homework correctly.
Good luck to Ken, he will need it.
dr grant
acemanvx@yahoo.com - 15 Mar 2006 05:43 GMT "You are talking about correcting one eye by -2D and the other by -3D are you? I hope your e values are appropriate."
My left eye's cornea is steeper by half a diopter and im a diopter more myopic in that eye but less astigmastic. The left eye is the dormant one so I want to balance it out and have both eyes be near each other instead of the left eye worse.
"Yes, but this is a topic (another one) that you know nothing about."
thats why I research all about vision online :) I know most of the basics and some of the intermediates.
"You will bore him stupid with your demands."
For the $150 I am paying him for less than an hour of his time, he had better be polite and patient. I know his time is very valuable and he gets paid a fortune for it. You would probably just sit tight and listen to any moron that pays you a fortune.
"like with myopia prevention, a topic of which I am also somewhat an expert."
Otis is probably the real expert here from what he says/claims. You can learn alot from Dr. Bates, he is qualified to say whatever he does because he is/was a licenced doctor! I improved my vision and now orthoK can take me to the point I dont need the crutches of glasses(bates words)
"I know of no OK designs that go to a 7mm OZ. It is not practical from a fluid hydraulics perspective."
he finds there is an improvement in night vision patient who are "20/happy." He suggests using a 7mm optical zone size for fitting post-surgical patients to control the size of the entrance pupil. Typically he uses a 10.6mm overall diameter lens for orthokeratology applications.
If it wasnt pratical, why does it exist? Reguardless, I will ask Dr. Maller what he thinks of 7mm zone orthoK and if he thinks its approperate for me or anyone. I dont know if 6mm is going to be enough because of my huge pupils. 7mm makes me feel much better.
"Your astigmatism is not going to be corrected by OK. Oblique cyls do not reduce and in many cases will get worse with OK. You have not done your homework correctly."
WTR astigmatism up to 1.50 D and ATR or oblique astigmatism up to 0.75 D can be corrected.
This is what I found when I researched. Your experience is what matters. Have you ever seen anyone improve ATR or OBL astigmatism with orthoK? If not, why isnt it possible and why do they claim up to -.75 is possible?
The amount of astigmatism you can treat with ortho-K depends on several factors, including the existing degree of myopia and the type of reverse-geometry lenses being used. For low amounts of simple astigmatism, elliptical lenses (rather than reverse geometry) may be useful, he explains. For example, for 2.00D of simple astigmatism, Dr. Day would fit a lens with eccentricity value of 0.8 fitted on-K to perform orthokeratology.
CatmanX - 15 Mar 2006 07:06 GMT > My left eye's cornea is steeper by half a diopter and im a diopter more > myopic in that eye but less astigmastic. The left eye is the dormant > one so I want to balance it out and have both eyes be near each other > instead of the left eye worse. Curve has minimal effect with 1D difference. You are still attempting to create a 1D variance.
> thats why I research all about vision online :) I know most of the > basics and some of the intermediates. You know little of the basics, so stop telling people how to do it.
> For the $150 I am paying him for less than an hour of his time, he had > better be polite and patient. I know his time is very valuable and he > gets paid a fortune for it. You would probably just sit tight and > listen to any moron that pays you a fortune. At $150.00 he is giving his time away. Lawyers will charge 10x that amount.
> Otis is probably the real expert here from what he says/claims. You can > learn alot from Dr. Bates, he is qualified to say whatever he does > because he is/was a licenced doctor! I improved my vision and now > orthoK can take me to the point I dont need the crutches of > glasses(bates words) Cletis is not an expert, Bates was less of an expert. Bates knew nothing and made mistakes in his assessments. If you knew anything about eyes you would see that straight away.
> he finds there is an improvement in night vision patient who are > "20/happy." He suggests using a 7mm optical zone size for fitting > post-surgical patients to control the size of the entrance pupil. > Typically he uses a 10.6mm overall diameter lens for orthokeratology > applications. Post RS is not OK. They are both RGLs but share nothing else.
> If it wasnt pratical, why does it exist? Reguardless, I will ask Dr. > Maller what he thinks of 7mm zone orthoK and if he thinks its > approperate for me or anyone. I dont know if 6mm is going to be enough > because of my huge pupils. 7mm makes me feel much better. 7mm OZ is for post RS, not OK. The effect will diminish significantly.
> WTR astigmatism up to 1.50 D and ATR or oblique astigmatism up to 0.75 > D can be corrected. Where did you read that rubbish? Roughlty 1/2 wtr cyl will reduce, not all and atr and oblique cyls do not change or get worse. Read the literature.
> This is what I found when I researched. Your experience is what > matters. Have you ever seen anyone improve ATR or OBL astigmatism with > orthoK? If not, why isnt it possible and why do they claim up to -.75 > is possible? No, I hope like hell it doesn't get worse or not take it on at all. When toric OK is available then it is feasible, but outside of Switzerland I don't know of anyone doing it.
> The amount of astigmatism you can treat with ortho-K depends on several > factors, including the existing degree of myopia and the type of [quoted text clipped - 3 lines] > Day would fit a lens with eccentricity value of 0.8 fitted on-K to > perform orthokeratology. This is not an RGL it is a standard design.
acemanvx@yahoo.com - 16 Mar 2006 05:48 GMT "Curve has minimal effect with 1D difference. You are still attempting to create a 1D variance."
no reason why you cant correct one eye less than the other. If orthoK can be used for monovision, I see no reason why it cant fix my anisometropia
"Cletis is not an expert, Bates was less of an expert. Bates knew nothing and made mistakes in his assessments. If you knew anything about eyes you would see that straight away."
thousands of people have improved their vision the Bates way. I have a book on natural vision improvement and in the testimonals, we have people improving 2 or 3 diopters! One guy went from -8 to -4! Another went from -5 to -2.25! I think he no longer wears glasses except for driving now.
"Post RS is not OK. They are both RGLs but share nothing else."
I cant find much on 7mm zones on google for orthoK. I will ask Maller if its possible and festable, especially for me. If not, ill take 6.5mm zone. Maller will measure my pupils in darnkess, dim light and room light. He will advise if my pupil size will be too much of a problem with 6.5mm orthoK. I may experience some slight vision quirks in dim light but if its not bad, I can deal with it. He will tell me what I can expect.
"Where did you read that rubbish? Roughlty 1/2 wtr cyl will reduce, not
all and atr and oblique cyls do not change or get worse. Read the literature."
Im sure theres toric OK out there. Maller will advise me on this and if he feels theres a toric OK solution for my astigmastim.
I agree with what Otis said. OK is the only way I can significentally improve my UCVA safely. Intacs is safer than prk and lasik but riskier than orthoK and costs far more. Lasik is popular but ive seen way too many bad things about it to bother taking the risk. Too risky and not reversable. Ragnar, SErebel and RT wouldnt be singing its praises if lasik didnt go perfect for those 3 men. They all acknowleged that they could have been the one with a bad lasik experience. Its like rolling the dice. If Maller says im not a good candidate for orthoK I will just stick to glasses and trying my best to improve my vision naturally. Ill probably get down to -3 with NVI but thats it. I should be thankful im not a -10 or anything heh.
Dan Abel - 16 Mar 2006 06:28 GMT > thousands of people have improved their vision the Bates way. I have a > book on natural vision improvement and in the testimonals, we have > people improving 2 or 3 diopters! One guy went from -8 to -4! Another > went from -5 to -2.25! I think he no longer wears glasses except for > driving now. That's nothing. Rishi claims a 20D improvement using Bates.
 Signature Dan Abel dabel@sonic.net Petaluma, California, USA
CatmanX - 16 Mar 2006 11:52 GMT Precisely Dan. The problem with these ancedotal testimonials is they do not have any validity. Who says they improved their eyes? WHere is the OD or MD that tested pre and post treatment that verifies this? I have seen several hundred presumed improved myopes. Funny though, not one has had any subjective myopia reduction. They still read the same on the letter chart and end up with the same script.
Repeat NOT ONE HAS EVER GOT BETTER.
dr grant
acemanvx@yahoo.com - 16 Mar 2006 17:04 GMT "That's nothing. Rishi claims a 20D improvement using Bates."
dont see how improving 20 diopters is possible. This would mean severe axial enlongation and you cant reverse axial myopia. I have heard of a few rare cases of a 5 diopter improvement but my research and reading the testimonals show most people improving from half diopter to 3 diopters. It works but cant do the impossible. I improved my vision by a diopter so far and will probably improve an additional diopter. I will probably get into the -3 range. I used to be in the -5 range, now I am in the -4 range.
"I have seen several hundred presumed improved myopes. Funny though, not one has had any subjective myopia reduction. They still read the same on the letter chart and end up with the same script."
well I did. Did all those people have no pseudomyopia? I have pseudomyopia and by improving upon this, my subjective refraction changed. I have gotten cycloplegia and this further reduced my pescription. I will improve down to whatever my axial myopia is. pseudomyopia is something that I will make go away.
RT - 16 Mar 2006 14:05 GMT > I see no reason why it cant fix my > anisometropia I read about this guy who was able to fix his anisometropia with colloidal silver. He washed his eye in it every morning. It's fairly easy to order over the internet, or you can purchase your own set up to make it at home.
 Signature ~RT
otisbrown@pa.net - 15 Mar 2006 22:08 GMT Dear AceMan,
Subject: Correction of your statement.
Steve Leung OD is the expert of the preventive second-opinion. I only suggest that you be informed of this second-opinion before you begin wearing a minus lens all the time.
Ace> "like with myopia prevention, a topic of which I am also somewhat an expert."
Otis> If you had been informed ot the preventive second-opinion, and USED IT WISELY, your refractive state would be positive, and you would be passing the DMV. That is what you needed -- but never received.
Ace> Otis is probably the real expert here from what he says/claims.
Otis> I make a statement ONLY about the behavior of all natural (primate) eyes -- when tested on an "engineering" level. I expect that the person interested in the preventive second-opinion should review this proven behavior -- and decide if "prevention" is what he is willing to do FOR HIMSELF. That is your right.
You can learn alot from Dr. Bates, he is qualified to say whatever he does because he is/was a licenced doctor!
Otis> Bates was a well-respected second-opinion ophthalmologists of 80 years ago.
I improved my vision and now orthoK can take me to the point I dont need the crutches of glasses(bates words)
Otis> If you have a "taget", then I suggest you plan to pass the DMV in your state -- with no minus lens. If OrthoK can do that -- then you have achieved your goal.
Good luck!
Otis
Dr. Leukoma - 19 Mar 2006 14:00 GMT > I have repeatedly written of having prescribed OK for many years. I > have disagreed with many, such as Greg Gemoules about OK, when he has > never practiced it. You have once again failed to listen, like with > myopia prevention, a topic of which I am also somewhat an expert. You almost got this one past me, Grant. You are incorrect to say that I have never practiced OK. I just don't do much of it. Most of the reverse geometry contact lenses in my practice are used for post-refractive fittings.
I believe that we have one fundamental disagreement over OK, which is a disagreement over the safety of OVERNIGHT OK, and putting children into overnight OK. I am not alone in the opinion that overnight OK is inadvisable for children.
I am also aware of the reports of damaging ulcerative keratitis in children undergoing overnight OK appearing in the peer-reviewed literature. I am aware that this kind of adverse publicity is damaging to the market for OK and to practices heavily reliant on OK. Please note that I am not the author of any of these case reports.
DrG http://www.coppellfamilyeyecare.com
acemanvx@yahoo.com - 19 Mar 2006 19:50 GMT has anyone heard about corneal molding where special eyedrops are inserted to make the cornea more malable then you only need to wear orthoK once a week or less? This would make orthoK explode in popularity and possibily make lasik nearly obsolete except for those with very high pescriptions.
acemanvx@yahoo.com - 10 Mar 2006 12:03 GMT His formula says theres a .25 diopter regression after 4 hours and a .5 diopter after 10 hours. Wont make a difference to me since ill be undercorrected anyway.
He also states a .75 diopter regression after 16 hours for 3 diopter correction. Ok so ill just move a couple inches closer to the computer monitor, no biggie.
He also found that when comparing the regression at seven-day, 30-day and 90-day intervals, the amount of regression appeared to slightly decrease with time
additionally, orthoK was preferred by a higher percentage of subjects than glasses or soft contacts. This means your more likley to be happy with orthoK than with glasses!
Before enrolling in the study, 82 percent of the subjects were soft contact lens wearers, and at the conclusion of the study, only 18 percent of them preferred to continue to wear soft contact lenses. The subjects who preferred soft contact lenses or spectacle correction over Paragon CRT lenses were the ones who reported the most complaints of lens discomfort and glare or flare.
I cant find much more info, but from what I can see, -6 diopters is the limit for 5mm orthoK, -4 for 6mm and -3 for 7mm.
5mm orthoK displaces 4mm of tissue per diopter(4x6=24) 6mm orthoK displaces 6mm of tissue per diopter(6x4=24) 7mm orthoK displaces 8mm of tissue per diopter(8x3=24)
"Of course the amount of tissue displaced will vary with the thickness of the epithelium, and is not the same for everybody."
The above figures are for a thick epithelium. If mine is average thickness, ill expect an improvemen of -2.25 or -2.5 diopters plus a reduction or elimination of my astigmastim.
DrG, you are presbyopic so you know full well the benefits of your -3.5 pescription in seeing clearly from 11.5 inches. If you sit about 2 feet from the computer, a -1.75 undercorrection is needed. If you got OrthoK and fully corrected, youd need reading glasses for near and intermediate. If your OrthoK undercorrected you, you wont need glasses except for reading fine print or for driving and watching movies.
CatmanX - 10 Mar 2006 12:14 GMT f.ck, I laughed so hard I nearly shat.
Lou Coma knows more about the math of OK than you and he doesn't know the start of it as he does not do it. However, he does know math and he knows that the bigger the zone, the smaller the change.
Now to you Nancy. You are stupid. You post crap that is not worthy of posting and if I were moderator (Christ I wish I was) you would never post here or anywhere again.
You don't know sh.t. You don't know the start of sh.t. You know OK even less.
Just PISS OFF and stop annoying the general public with your sh.t.
dr grant
acemanvx@yahoo.com - 10 Mar 2006 12:21 GMT If you think you know so much, why dont you educate me instead of spouting off vuglarities? Teach me about OK, o master!
drgranthatesyou@hotmail.com - 10 Mar 2006 13:06 GMT Why would I waste my time. You are a parasite. You know noting and learn nothing.
Go away.
dr grant
Dan Abel - 10 Mar 2006 18:14 GMT > f.ck, I laughed so hard I nearly shat. CatmanX
acemanvx
coincidence?
> dr grant No capital "D". No period. Does "dr" stand for Donald Randolph, or "don't reply"?
 Signature Dan Abel dabel@sonic.net Petaluma, California, USA
Dr. Leukoma - 10 Mar 2006 13:40 GMT > His formula says theres a .25 diopter regression after 4 hours and a .5 > diopter after 10 hours. Wont make a difference to me since ill be [quoted text clipped - 39 lines] > intermediate. If your OrthoK undercorrected you, you wont need glasses > except for reading fine print or for driving and watching movies. Your figures are close to mine. When I say thickness, I mean the saggital thickness, which is the difference in thickness between the center and the edge of the treatment area. OK causes the central cornea to thin by pushing epithelium out into the mid-periphery, where it piles-up. Helen Swarbrick published an excellent study on this a few years back. She found that the average dioptric change was 1.66. This was accomplished by an average central thinning of 9.3 microns and an average mid-peripheral thickening of 10.9 microns. The effective saggital depth is about 20 microns, or 12 microns/diopter for a 6 mm zone. With a total of 50 microns to play with (25+25), this works out to about 2.75 to 3.00 diopters of change for a 7.0 mm zone, ASSUMING the lens mechanics would permit it.
The above is only theoretical, which is why I asked Dr. Mason to comment from his personal experience. Instead, he made some obscure reference to the founder and patron saint of orthokeratology, George Jessen, and did not answer the question directly.
With respect to being presbyopic, my preference is for 100% clarity at infinity, and 100% clarity at whatever nearpoint distance I am working, which means that I prefer to wear progressive lenses over my contact lenses. I have zero tolerance for blur, and zero tolerance for fluctuating vision. This means that I would not be a good candidate for either OK or LASIK.
DrG http://www.coppellfamilyeyecare.com
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