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Medical Forum / General / Vision / December 2005Myopia undercorrection in juveniles slows progression
I'm sure this study will keep Otis going for a while. ~~~~~~~~~~~~~~~~~~ Monovision slows juvenile myopia progression unilaterally J R Phillips Correspondence to: Dr J R Phillips Department of Optometry and Vision Science, University of Auckland, Private Bag 92019, Auckland, New Zealand; j.phillips@auckland.ac.nz Aim: To evaluate the acceptability, effectivity, and side effects of a monovision spectacle correction designed to reduce accommodation and myopia progression in schoolchildren. Methods: Dominant eyes of 11 year old children with myopia (1.00 to 3.00 D mean spherical equivalent) were corrected for distance; fellow eyes were uncorrected or corrected to keep the refractive imbalance 2.00 D. Myopia progression was followed with cycloplegic autorefraction and A-scan ultrasonography measures of vitreous chamber depth (VCD) for up to 30 months. Dynamic retinoscopy was used to assess accommodation while reading. Results: All children accommodated to read with the distance corrected (dominant) eye. Thus, the near corrected eye experienced myopic defocus at all levels of accommodation. Myopia progression in the near corrected eyes was significantly slower than in the distance corrected eyes (inter-eye difference = 0.36 D/year (95% CI: 0.54 to 0.19, p = 0.0015, n = 13); difference in VCD elongation = 0.13 mm/year (95% CI: 0.18 to 0.08, p = 0.0003, n = 13)). After refitting with conventional spectacles, the resultant anisometropia returned to baseline levels after 918 months. Conclusions: Monovision is not effective in reducing accommodation in juvenile myopia. However, myopia progression was significantly reduced in the near corrected eye, suggesting that sustained myopic defocus slows axial elongation of the human eye. Glenn Hagele Executive Director USAEyes.org "Consider and Choose With Confidence" Email to glenn dot hagele at usaeyes dot org http://www.USAEyes.org http://www.ComplicatedEyes.org I am not a doctor. Naw. It means that monovision increases the development of anisometropia. DrG Dear Glenn, I'm sure this study will keep Otis going for a while. Otis> My family received threats from Neil Brook. I will not respond. Otis> If you want Neil to control this forum -- then you can have him. Otis >Dear Glenn, > [quoted text clipped - 5 lines] > >Otis I have NEVER threatened you with anything other than LEGAL action. Sick, sick old man. He is what they call a "drama queen." DrG > I'm sure this study will keep Otis going for a while. > > Otis> My family received threats from Neil Brook. I will not respond. Good. Wait a minute, what are you doing here? If this is your idea of not responding, I'd hate to hear your ideas about other stuff. > Otis> If you want Neil to control this forum -- then you can have him. This is an unmoderated group. Nobody is in charge. >This is an unmoderated group. Nobody is in charge. THAT is self evident. Glenn Hagele Executive Director USAEyes.org "Consider and Choose With Confidence" Email to glenn dot hagele at usaeyes dot org http://www.USAEyes.org http://www.ComplicatedEyes.org I am not a doctor. Every practitioner has experience with children who have developed monovision naturally. Why does one eye continue to progress faster than the other when neither eye is corrected for distance? Because one eye is used for reading, and that eye continues to show the most progression, despite the fact that it is the eye with the most myopic defocus. DrG As much as I'm trying to stay out of discussions on myopia development, this post screams for a response. Everyone knows that the focusing mechanisms are linked, so that humans cannot independently accommodate with one eye, and certainly my years of experience confirm that anisometropia is pretty much stable over a lifetime except when pathological changes are in play. By far the vast majority of myopic anisometropes started out as hyperopic anisometropes of the same dioptric difference between the eyes. In fact, in over 30 years of practice I can't recall a single case of an otherwise normal child having no anisometropia in infancy developing it later. (Obviously optometrists don't see many of them before they start getting myopic, so maybe that's what's influencing your statement. Of course this is changning with early exams being done, so we will start seeing more and more of these "missed" anisometropes when they are still hyperopic, or antimetropic.) w.stacy, o.d. > Every practitioner has experience with children who have developed > monovision naturally. Why does one eye continue to progress faster [quoted text clipped - 4 lines] > > DrG Can you point me towards any studies that would confirm this? I don't disagree that congenital anisometropia might be preserved, but I have seen it develop and change as well. I think that there are some obvious flaws in the conclusions of the study. DrG I cannot. I agree with your flaws comment, and doubt seriously the study, esp. since it also indicated a resolution of "induced" anisometropia after discontinuance of the trial. If they'd totally cyclopleged the eyes before and after the trial, I think they would have found no real differences in the amouns of aniso. w.stacy, o.d. > Can you point me towards any studies that would confirm this? I don't > disagree that congenital anisometropia might be preserved, but I have [quoted text clipped - 4 lines] > > DrG FYI, I just received a copy of the full article from its author. Among the findings, both eyes got more nearsighted than baseline, but the distance corrected eye showed more change. DrG > FYI, I just received a copy of the full article from its author. Among > the findings, both eyes got more nearsighted than baseline, but the > distance corrected eye showed more change. A relatively small difference in refraction is probably of no practical consequence unless it is at the cutoff where corrective lenses are needed or the patient can easily do without them. (A change from -1 to -2 D would very likely have this implication, but -3 to -4 D would not.) > I'm sure this study will keep Otis going for a while. > [quoted text clipped - 34 lines] > in the near corrected eye, suggesting that sustained myopic defocus > slows axial elongation of the human eye. This is an interesting study, as one eye serves as the control for the other, thus controling for the age, refractive error, parental history, hours of near work bugaboos that have made matching controls so tricky. It was hoped that the monovision would reduce accommodation and the reduced accommodation would reduce progression. As designed, the dominant eye should have had no defocus at far, hyperopic defocus at near and no accommodation while the non dominant eye would have had myopic defocus at far, no retinal defocus at near and no accommodation. The design didn't work, as the children continued to accommodate. So instead, we got one eye accommodating with no retinal defocus at near or far and the other eye accommodating with myopic defocus at far and near. The myopic defocus eye slows axial growth despite the accommodation and the conclusion is that myopic defocus drives suppression of axial elongation, not that accommodation drives axial elongation. This finding makes sense of all the others that found undercorrecting myopia or using plus at near does not slow progression, as in those studies the subjects no myopic defocus at near. this poses a significant problem for myopia prevention, as the answer is unacceptable: maintain myopic blur at all distances. Given a choice between not being able to read due to blur or the risk of myopia, I think most of us in our Western, literate society would risk myopia and continue to read clearly. Dr Judy Ah, but, the contralateral eye with myopic defocus at far and near also showed myopic progression...just not as much. The author was kind enough to send me a PDF of the entire paper. DrG > Ah, but, the contralateral eye with myopic defocus at far and near also > showed myopic progression...just not as much. Of course, we all know that myopes are genetically programmed to progress and that they have a sluggish response to retinal blur; I thought it the final nail in the coffin for the "plus lens therapy" that accommodation was clearly not a factor in the slowing of progresssion. > The author was kind enough to send me a PDF of the entire paper. From your reading of the paper, do you buy that the dominant eye drove the accommodative response? That did seem weird to me, but then, most of my experience with monovision is with presbyopic patients. Dr Judy > DrG According to the paper, accommodation was determined using nearpoint retinoscopy, and that the dominant eye did indeed drive the accommodative response. After a mean duration of 18.7 months, the dominant eye showed an increase of 1.13D, while the non-dominant eye showed an increase of 0.58D. The group that immediately comes to mind in comparing and contrasting this study is the group of naturally-occurring anisometropic, monovision children and young adults whose accommodation is intact, yet they read with one eye and use the other eye for distance. My point to the author was that perhaps the results are not due to accommodation, but due to the fact that one eye is reading more than the other. DrG DrG Hi, for me as an individual study. I had different myopia vision in each eye. My right eye had worse myopia than my left eye. I did not wear glasses while i was a child even though I needed them because I did not like the way they looked on me. At around age 17, I started wearing glasses full time. At around age 21, the myopia in each eye was tested to be the same, so I had binocular vision. This is why you are only a -2.5 now and not a high myope. My brother also didnt like glasses and hes only a -1.25. I wish I knew about the dangers of the minus lenses as a child :( > This is why you are only a -2.5 now and not a high myope. My brother > also didnt like glasses and hes only a -1.25. I wish I knew about the > dangers of the minus lenses as a child :( If they're as dangerous as you say, we should petition the FDA to require warning labels. No, wait, that's already been tried. See.. I KNEW there was a conspiracy! -MT "If they're as dangerous as you say, we should petition the FDA to require warning labels." well glasses wont harm you physically. What we need is optometrists who arent so hasty to pescribe the minus lense but instead educate on the use of the plus lense. I wish mine told me "dont worry about the minus lense, just use reading glasses for all close work and you can keep your vision sharp" "You are talking about environmental factors." This explains why more and more people are becomming myopic. There were alot less myopes 20, 30, 40 years ago. "Glasses is generally about genetics and not environmental factors like otis might believe." Its true genes make you more suspectable to myopia, only you can prevent or slow it down. My brother accidently stopped his myopia from worsening. My sister's eyes got worse in a hurry once she got minus glasses and especially when she got contacts. "You can probably correct your vision with contacts and also marry a non- myopia female." I cant tolerate contacts and my eyes are too valuable to risk with refractive surgury, plus I dont consider myself a candidate either. An once of prevention is worth a pound of cure. Glasses will only aid me in seeing, they do nothing to cure or reverse myopia. I must suffer bad vision every living minute. It doesnt matter who marries who, anyone can become myopic if they use their eyes incorrectly like you did and still do. "You also read more books or stayed inside and watched tv and played video games?" so does almost everyone. Many people will ruin their eyes that way but can act quicky and use the plus lense to do damage control. Using the minus lense for reading is the worst thing one can do and you still do it! > well glasses wont harm you physically. What we need is optometrists who > arent so hasty to pescribe the minus lense but instead educate on the > use of the plus lense. Yes, but you believe that plus lenses prevent myopia. When you're perpetrating myths, people will take you more seriously if you learn to spell "lens." > I wish mine told me "dont worry about the minus > lense, just use reading glasses for all close work and you can keep > your vision sharp" Yes, but you believe that would have helped. Why has nobody published any convincing evidence that it does? Oh, yeah.. the conspiracy. > Its true genes make you more suspectable to myopia, only you can > prevent or slow it down. My brother accidently stopped his myopia from > worsening. My sister's eyes got worse in a hurry once she got minus > glasses and especially when she got contacts. My house hasn't once been trampled by elephants since I bought that elephant repellent. > I cant tolerate contacts and my eyes are too valuable to risk with > refractive surgury, plus I dont consider myself a candidate either. An > once of prevention is worth a pound of cure. So point us to one believable study that has been published to prove this. > Glasses will only aid me > in seeing, they do nothing to cure or reverse myopia. I must suffer bad > vision every living minute. It doesnt matter who marries who, anyone > can become myopic if they use their eyes incorrectly like you did and > still do. Otis has you believing it's your fault, and nobody will convince you otherwise. -MT acemanvx@yahoo.com wrote in news:1135464084.300462.211950 @g44g2000cwa.googlegroups.com: > This is why you are only a -2.5 now and not a high myope. My brother > also didnt like glasses and hes only a -1.25. I wish I knew about the > dangers of the minus lenses as a child :( Ace, i believe this is not true. You are talking about environmental factors. Glasses is generally about genetics and not environmental factors like otis might believe. You can probably correct your vision with contacts and also marry a non- myopia female. The genetics is that to have myopia you need two non-dominate alles ee if you have hetero alles like Ee then you do not have myopia I.E. if two myopia parents have a child, then that child will be myopia but if two non-myopia parents have a child, then there is a 50% chance that their child will be myopia if the parents are hetero alle or Ee acemanvx@yahoo.com wrote in news:1135464084.300462.211950 @g44g2000cwa.googlegroups.com: > This is why you are only a -2.5 now and not a high myope. My brother > also didnt like glasses and hes only a -1.25. I wish I knew about the > dangers of the minus lenses as a child :( It is probably more genetics than environment don't you think? You also read more books or stayed inside and watched tv and played video games? |
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