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Medical Forum / General / Vision / September 2007Contacts/astigmatism
Hi I hope someone on this very informative forum can fill me in on contacts and astigmatism. My astigmatism is low and in the past opticians have compensated for it by increasing my prescription. I hope that makes sense. I have friends who wear special lenses for astigmatism but they start higher than my -0.5. Please could someone explain how increasing the regular prescription helps correct the astigmatism? My full prescription is -3/-0.5 x 140 and -3.25 Thanks > My astigmatism is low and in the past opticians have compensated for it by > increasing my prescription. I hope that makes sense. It does indeed. Think about the "spoon" shape that is astigmatism. In the first eye you mentioned (the right?) the steepest meridian measures -3.50 and the flattest meridian is -3.00. It makes sense to average those two values and use -3.25. It's convenient that it works out to be the same as the left eye. With both eyes open, most people would not be bothered by the little bit of blur in the right eye. Most torics don't offer a -0.50 option because nobody buys them. -MT Astigmatism is curable, very easy. > Astigmatism is curable, very easy. No, Virginia, you've never seen anyone "cured" of astigmatism. -MT I've cured myself, you fool. > I've cured myself, you fool. You've cured yourself from admitting that it would have happened anyway. -MT What's the limit, before it's called 'true astigmatism'? Would it have happened anyway, if it were about 0.5d? Oops I meant: above 0.5d? What's the limit, before it's called 'true astigmatism'? Would it have happened anyway, if it were above 0.5 diopters? > What's the limit, before it's called 'true astigmatism'? How much rain do you need before it's called "true rain?" > Would it have happened anyway, if it were above 0.5 diopters? It is not rare for someone to "improve" by 0.50 D. Whether they "demonstrate the truths" or not. If it's 1.25 now, it may be 0.75 two years from now. Could also be 1.75. Best bet, if you had to predict, would be 1.25. -MT >> Would it have happened anyway, if it were above 0.5 diopters? You should also expect cyl (astigmatism) to vary 0.25 (or more) from morning to evening, in a diurnal cycle. It will also vary 0.25 from examiner to examiner, instrument to instrument, and measurement to measurement. -MT Hi, >It is not rare for someone to "improve" by 0.50 D. So, is that level of improvement common? What's the limit before it's considered 'unusual', then? >If it's 1.25 now, it may be 0.75 two years from now. >Could also be 1.75. Best bet, if you had to predict, would be 1.25. And two years is such a short time, no? Sorry. Rishi Giovanni Gatti (Zetsu), Lena102938, and Otis Brown are trolls who haunt s.m.v. Rishi has published, and is trying to sell worthless books. Otis is pathologically dishonest and actually hurts people. Following his advice can induce double vision in those not working closely with an eye doctor. Lena102938 uses anti-eye doctor rhetoric as a substitute for ANY actual information. It seems she now has to wear glasses and has developed a pathological (and ILLOGICAL) resentment toward the industry that "foisted these glasses upon her." You'd do well to ignore them and wait for responses from the caring, compassionate eye doctors who DO also participate in this site. Mike Tyner schreef: >> My astigmatism is low and in the past opticians have compensated for it by >> increasing my prescription. I hope that makes sense. [quoted text clipped - 3 lines] > and the flattest meridian is -3.00. It makes sense to average those two > values and use -3.25. Mike are you interested in talking this issue over? As you might know I disagree with you in this and I like to know what is your reason for prescribing that way. > It's convenient that it works out to be the same as the left eye. > > With both eyes open, most people would not be bothered by the little bit of > blur in the right eye. Why not let them try what please them best, with or without the correction for astigmatism. > Most torics don't offer a -0.50 option because nobody buys them. I agree, that's why I often use a -0,75 instead, when I want to let them try a soft toric contactlens, even if the amount of measured astigmatism is 0.5 . Greetings, Jan Oudesluys (normally Dutch spoken) > Mike are you interested in talking this issue over? > As you might know I disagree with you in this and I like to know what is > your reason for prescribing that way. Good to hear from you again. I don't see what you're disagreeing about. If you're fitting spherical lenses you use spherical equivalent. If you're fitting torics, you overrefract. Many times if you overrefract over spherical contacts, you measure less astigmatism, demonstrating the "masking" effect. > Why not let them try what please them best, with or without the correction > for astigmatism. If I can make them buy $100 lenses, why "settle" for $25 lenses? > I agree, that's why I often use a -0,75 instead, when I want to let them > try a soft toric contactlens, even if the amount of measured astigmatism > is 0.5 . And if you overrefract you'll often find the cyl overcorrected not 0.25, but 0.50 or more. What was -050 x 090 is now -050 x 180. And when the other eye is completely spherical, even perfect toric correction doesn't make much difference with both eyes open. -MT > > Why not let them try what please them best, with or without the correction > > for astigmatism. > > If I can make them buy $100 lenses, why "settle" for $25 lenses? Mike Mike Mike, please explain the last sentence before Lena, Otis, Zetsu et al jump on you! It sounds as if your goal is to get your patient to buy the most expensive product. Is this what you meant to say????? >> If I can make them buy $100 lenses, why "settle" for $25 lenses? > > Mike Mike Mike, please explain the last sentence before Lena, Otis, > Zetsu et al jump on you! It sounds as if your goal is to get your > patient to buy the most expensive product. Is this what you meant to > say????? I thought the sarcasm was pretty obvious. I'm tired of writing for the least common denominator. It might be clearer to Jan if I said that the fitting fees _and_ the lens cost go up if I open a toric trial lens. I don't offer torics unless there's a subjective sense of blur with spheres. If it ain't broke don't fix it. -MT > >> If I can make them buy $100 lenses, why "settle" for $25 lenses? > [quoted text clipped - 13 lines] > > -MT Mike, It was pretty obvious, It seams like Jan do not understand simple physical properties of astigmatism. (like it is no "perfect regular" astigmatic eye; no perfect contacts:they have some precision, can shift; ) > >> If I can make them buy $100 lenses, why "settle" for $25 lenses? > > [quoted text clipped - 9 lines] > cost go up if I open a toric trial lens. I don't offer torics unless there's > a subjective sense of blur with spheres. That's been my experience. I have a signicant amount of irregular astigmatism in my right eye, I'm guessing partially due to the buckle. It's 1.75D. I don't know if spherical would do much since I'm plano. So I get a box of toric lenses. They are in fact a lot more expensive. In a few months, I go back in for a recheck. They've rotated. They were the perfect prescription according to the phoropter, but the phoropter doesn't rotate. The doctor sticks his finger in my eye and rotates the lens back to where it belonged. I could see better. The doctor had me blink and it rotated right back again. We tried it again. So I get to buy another box of lenses, even though the other box was half full. > So I get to buy another box of lenses, even though the > other box was half full. That's why the manufacturers provide single trials at no charge. -MT Mike Tyner schreef: >> Mike are you interested in talking this issue over? >> As you might know I disagree with you in this and I like to know what is [quoted text clipped - 5 lines] > > If you're fitting spherical lenses you use spherical equivalent. That's where we differ, I fit a spherical with just the spherical amount, not the equivalent. IMO the vision acuity does not increase when adding half off the amount of refracted astigmatism. And, trying to avoid a conflict with dear Otis I prescribe as less minus as possible (grinssssss). > If you're fitting torics, you overrefract. > [quoted text clipped - 5 lines] > > If I can make them buy $100 lenses, why "settle" for $25 lenses? We, Dutch, are famous for getting things as cheap as possible......... >> I agree, that's why I often use a -0,75 instead, when I want to let them >> try a soft toric contactlens, even if the amount of measured astigmatism >> is 0.5 . > > And if you overrefract you'll often find the cyl overcorrected not 0.25, but > 0.50 or more. What was -050 x 090 is now -050 x 180. There I have other experiences. > And when the other eye is completely spherical, even perfect toric > correction doesn't make much difference with both eyes open. Your right, but what an easy customers you must have in general Mike, mine are quite demanding and keen on sharp vision in both eyes and they want to pay for it and I'm so willing to please them and ............... myselves. > That's where we differ, I fit a spherical with just the spherical amount, > not the equivalent. Then you never do a sphere overrefraction? > IMO the vision acuity does not increase when adding half off the amount of > refracted astigmatism. In my experience, patients say it does. > And, trying to avoid a conflict with dear Otis I prescribe as less minus > as possible (grinssssss). I never saw much sense in trying to practice what Otis preaches. -MT Mike Tyner schreef: >> That's where we differ, I fit a spherical with just the spherical amount, >> not the equivalent. > > Then you never do a sphere overrefraction? Yes, always. >> IMO the vision acuity does not increase when adding half off the amount of >> refracted astigmatism. > > In my experience, patients say it does. When I overrefract and ask if they could read the next line or some characters more in the same line by placing more minus , the answer most of the time is no. Even theoretically I can't imaging how the vision could increase. >> And, trying to avoid a conflict with dear Otis I prescribe as less minus >> as possible (grinssssss). > > I never saw much sense in trying to practice what Otis preaches. Same to me, in fact no sense at all. Jan (normally Dutch spoken)
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