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Medical Forum / General / Vision / February 2005Dominant eye alternation
I have mismatched eyes nowadays and see mostly with one eye (R) for distance then switching to the L for closeup. I don't seem to have a dominant eye anymore. The swap is imperceptible by me. Things are in focus at two points, using either eye. Naturally my 3D perception is limited. However I wonder is one's 'dominant eye' such a changeable thing, altering at will depending on the available focus? I'd heard that it was established early in life and stayed with us. FWIW I'm -8 or so (L) and -4 (R). The -8 used to be -4 til recently when, 3 years after retinal reatachment, a cataract is now starting to develop. So the lens seems to be developing a higher and higher index rating. This is not fully correctable with glasses so I have blurry distance vision and a focal range of 150mm in that eye. I'm due for cataract surgery (L) in the public health system here midway through this year. Hope to see better with L and wear a contact in the R. Brian  SignatureAuckland NEW ZEALAND > I have mismatched eyes nowadays and see mostly with one eye (R) for > distance then switching to the L for closeup. I don't seem to have a [quoted text clipped - 15 lines] > > Brian It's possible to have a dominant eye that is not your clearest eye. The dominant eye may have been your clearest eye as a child when your vision was developing, but as you now know vision can change throughout life. So while it's still your dominant eye, it's no longer your clearest eye. AFAIK, the dominant eye does not change once it's set during childhood - though I don't know this for a 100% fact. I bet you'll love your new vision with non-cataractous left eye and contact lens right eye. Dom > AFAIK, the dominant eye does not change once it's set during childhood - > though I don't know this for a 100% fact. It isn't going to switch for no reason. I was right-eyed for most of my life. I switched to left-eyed once the cataract in my right eye got bad enough. I switched back to right-eyed when I had cataract surgery in the right eye. Note that eye-hand coordination is a learned skill. When you switch eyes you lose it and have to learn again. SignatureDan Abel Sonoma State University AIS dabel@sonic.net love is blind, in fact. >I have mismatched eyes nowadays and see mostly with one eye (R) for > distance then switching to the L for closeup. I don't seem to have a [quoted text clipped - 5 lines] > > I'd heard that it was established early in life and stayed with us. As a student I did a research paper on eye dominance and found that the dominant eye depends upon which method of testing dominance you use. There are about a dozen different ways to test dominance and, in any individual, the different ways do not all yield the same eye. For example, a test of retinal rivalry will not give the same eye as a test of sighting or a test of tolerance to blur. So I would say that is alterable depending upon the situation, and is one of the reasons that monovision (one eye for distance, one for near) contact lens correction works. Dr Judy > FWIW I'm -8 or so (L) and -4 (R). The -8 used to be -4 til recently when, > 3 years after retinal reatachment, a cataract is now starting to develop. [quoted text clipped - 5 lines] > > Brian when one eye is set for distance and one for near - what is the prescription of the near contact lens? is it relative to the distance eye? > when one eye is set for distance and one for near - what is the > prescription of the near contact lens? is it relative to the distance > eye? No, determined relative to the distance prescription for the near eye. The near lens power is determined by how much "add" the patient needs to read, then that add is added to the distance power needed in that eye. Eg: distance Rx is -3.00, add is +1.00, near lens is then -2.00. The add used is determined by the fitter using trial contact lenses. Selection depends upon the patient's bifocal add, what type of near work is done and how much distance blur the patient can tolerate. Dr judy >> when one eye is set for distance and one for near - what is the >> prescription of the near contact lens? is it relative to the distance [quoted text clipped - 10 lines] > > Dr judy I suffer from mild myopia, average -2.5 D. I enquired with my optician on what prescription to use for a pair of reading glasses, so that I don't have to accommodate and she suggested +1.5 to the existing prescription. I wonder if this is suitable for use with computers since it's recommended to sit as far back from the monitor as possible. >>> when one eye is set for distance and one for near - what is the >>> prescription of the near contact lens? is it relative to the distance [quoted text clipped - 16 lines] > wonder if this is suitable for use with computers since it's recommended > to sit as far back from the monitor as possible. It depends upon your age and the distance viewed. If you do not want to accommodate at all (why is this your goal?), then you need a +2.00 or +2.50 add for the usual near viewing distance of 16 to 18 inches, +1.50 ad for a computer at 20 to 22 inches and +1.00 add for a computer at 24 to 30 inches. It doesn't matter what your distance Rx is, these are all specified as adds. For example, if you are a 2.50 myope, reading at 16 inches the add is +2.50 and the resultant (-2.50 +2.50) is zero, ie take your glasses off. For the computer at 28 inches the resultant (-2.50 +1.00) is -1.50 readers. Be sure to have your eye examiner demonstrate the resultant single vision reading glasses in a trial frame and check the actual range of clear vision to make sure it suits you. Dr Judy >> I suffer from mild myopia, average -2.5 D. I enquired with my optician on >> what prescription to use for a pair of reading glasses, so that I don't [quoted text clipped - 7 lines] > ad for a computer at 20 to 22 inches and +1.00 add for a computer at 24 to > 30 inches. I'm hoping my myopia will improve if I accommodate less. Will see how it goes... >>> I suffer from mild myopia, average -2.5 D. I enquired with my optician >>> on what prescription to use for a pair of reading glasses, so that I [quoted text clipped - 10 lines] > I'm hoping my myopia will improve if I accommodate less. Will see how it > goes... There is no evidence that reducing accommodation will reverse myopia. There is some evidence that near work is a factor in the development of myopia in the first place, however, it is not clear that accommodation is the reason for the near work factor. Family history of myopia explains about 85% of myopia. If you think you have pseudo myopia, ask your eye doctor next time you are in for an exam to do a cycloplegic refraction. The difference, if any, between your non cycloplegic and your cycloplegic refraction is the maximum amount of myopia you can expect to reduce by not accommodating. Dr Judy > If you think you have pseudo myopia, ask your eye doctor next time you are > in for an exam to do a cycloplegic refraction. The difference, if any, > between your non cycloplegic and your cycloplegic refraction is the > maximum amount of myopia you can expect to reduce by not accommodating. Good idea. I'll be doing that soon. > > If you think you have pseudo myopia, ask your eye doctor next time you are > > in for an exam to do a cycloplegic refraction. The difference, if any, > > between your non cycloplegic and your cycloplegic refraction is the > > maximum amount of myopia you can expect to reduce by not accommodating. > > Good idea. I'll be doing that soon. Don't be idiotic. Let them remain in their harmful ignorance. You remain pure, don't let them ruin your eyes with chemicals. It's very easy to learn how to see again, just study the books and start the practice of the rest methods. Laughter plays tricks with your eyes http://abc.net.au/science/news/stories/s1294404.htm ... "Normally people just don't see both [versions] at the same time," he says. But when you laugh the images blend together and the illusion is lost leaving only a flat 2D drawing. ... > >>> I suffer from mild myopia, average -2.5 D. I enquired with my optician > >>> on what prescription to use for a pair of reading glasses, so that I [quoted text clipped - 23 lines] > > Dr Judy Hey Andrew, Its great to see someone from Singapore on this newsgroup. With a +1.50 Add you will not need to accomodate when looking at an object at 66.66 cm. You will however have to accomodate when looking closer. Roland J. Izaac Optometrist Singapore > >> when one eye is set for distance and one for near - what is the > >> prescription of the near contact lens? is it relative to the distance [quoted text clipped - 16 lines] > if this is suitable for use with computers since it's recommended to sit as > far back from the monitor as possible. > Hey Andrew, Its great to see someone from Singapore on this newsgroup. > > With a +1.50 Add you will not need to accomodate when looking at an object > at 66.66 cm. You will however have to accomodate when looking closer. 66.66 cm seems pretty decent. The Singapore Health Promotion Board recommends at least 50 cm from the monitor and 30 cm for regular reading materials. > > Hey Andrew, Its great to see someone from Singapore on this newsgroup. > > [quoted text clipped - 4 lines] > recommends at least 50 cm from the monitor and 30 cm for regular reading > materials. For a young kid with short arms, maybe; I would keep reading materials at least 40 cm. away At this distance (with your 1.50 add) you would still need to accomodate by 1.00D Have you read the COMET study? Roland J. Izaac > For a young kid with short arms, maybe; I would keep reading materials at > least 40 cm. away [quoted text clipped - 3 lines] > > Have you read the COMET study? http://www.nei.nih.gov/neitrials/static/study9.asp Yes, they seem to have concluded plus lenses only help in the first year on wearing them, then the eye adapts or something. I also read that chicks which were made to wear plus lenses became hyperopic and those wearing minus lenses became myopic. See http://vision.berkeley.edu/wildsoet/myopiaPrimer.html under "Animal models for myopia & emmetropization". So it's actually possible to induce myopia & hyperopia just by wearing wrong prescriptions? > http://www.nei.nih.gov/neitrials/static/study9.asp > Yes, they seem to have concluded plus lenses only help in the first year [quoted text clipped - 5 lines] > for myopia & emmetropization". So it's actually possible to induce myopia > & hyperopia just by wearing wrong prescriptions? Only in neonates (newborns). Those experiments were done with newly hatched chicks who were forced to wear high (10D) power lenses to simulate being born with high refractive error. Both The simulated myopes (wearing +10) and the simulated hyperopes (-10) altered eye growth so that the eye/lens system had a net refractive error approaching zero. This process is called emmetropization and no relevance to the development and/or correction of refractive error in non neonates. In humans, babies born with large refractive do the same thing so that by age 2 or 3, most children do not have significant refractive error. Emmetropization does not occur after age 3 to 4, which is why refractive error that develops after that age is not self correcting and people need glasses. Those who advocate using plus lenses to reverse myopia in adults ignore the fact that it would only be effective in babies and toddlers. Dr Judy > In humans, babies born with large refractive do the same thing so that by > age 2 or 3, most children do not have significant refractive error. [quoted text clipped - 6 lines] > > Dr Judy Although you have never witnessed it, there are thousands of people who are recovering from refractive errors just by rest methods. It is very easy to do it temporarily, more difficult to do it permanently. Continued treatment brings about a complete cure if the patient continues. |
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