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Medical Forum / General / Vision / March 2006What type of lens?
My prescription is Distance: -2.25 left eye, -2.25 right eye, for reading it is +2.00 right and left (add +2.50 for progressives). My reading without glasses is good. My intermediate vision is poor with or without my current glasses. Distance vision poor. What's a good option for this type of situation: single lens for distance and take them off to read OR a progressive bifocal. How well would the progressive address the intermediate area? Thanks > My prescription is Distance: -2.25 left eye, -2.25 right eye, for > reading it is +2.00 right and left (add +2.50 for progressives). [quoted text clipped - 6 lines] > > Thanks > My prescription is Distance: -2.25 left eye, -2.25 right eye, for > reading it is +2.00 right and left (add +2.50 for progressives). [quoted text clipped - 6 lines] > > Thanks A progressive lens does address the intermediate area, whereas a bifocal does not (it is basically 2 SV lenses stuck together). However, if you have never worn progressives, they take some getting used to (accommodation) and the intermediate area of the lens is relatively small. You need to be motivated to wear progressives, but once you adapt they will usually become second nature. Find a reputable optician that gives you a 30 day exchange warranty if you don't like the progressives and want to switch to SV or bifocals. Whether or not you need a lens for intermediate vision depends on a number of lifestyle factors, such as how much computer work you do and how far the monitor is from your eyes. If you use a computer, I would measure the distance of your eyes to your monitor. Keep in mind that most reading powers at optimized for about 13 inches. maybe get bifocals and use the upper part for distance, the lower part for intermediate and peak under your glasses or take them off for reading And get a sore neck from tilting your head to see the computer.\ Ace aces another one. dr grant I spend about 10 hours a day on a computer. I can see the screen fine with glasses and can read without the glasses. The problem is distance vision and intermediate, by which I mean anything after about 4 feet or so. I may just go with a single vision lens for distance and take the glasses off while working. Of course, when I have the glasses on I can't read so I'll have to take them off to read. What a quandry! > mean anything after about 4 feet or so. I may just go with a single > vision lens for distance > and take the glasses off while working. Of course, when I have the > glasses on I can't read > so I'll have to take them off to read. What a quandry! I have a similar problem and I'm very happy with my solution, which is progressives that are compromised for office work. They're a little blurry for driving but still well within legal limits. Ask your doctor about making a progressive with -1.75 right, -1.75 left, add +2.00 -MT, OD >My prescription is Distance: -2.25 left eye, -2.25 right eye, for >reading it is +2.00 right and left (add +2.50 for progressives). If the add power is +2.00 at 16" and you actually read at that distance then that is what should be used. Increasing the add for progressives was ok 25 years ago but does not work with recent designs. An experienced optician will sort this out by using various methods that might include a phone call to the doctor. >My reading without glasses is good. My intermediate vision is poor with >or without my current glasses. Distance vision poor. What's a good >option for this type of situation: single lens for distance and take >them off to read OR a progressive bifocal. You will take them off to read either way, less frequently if you choose multifocals. >How well would the >progressive address the intermediate area? >Thanks Good for short term tasks (speedometer) poor for medium and long term tasks (desktop monitor). Talk to your doctor and optician for more details and specific recommendations. Hope this helps, Robert Martellaro ~~~~~~~~~~~~~~~~~~ Optician/Owner Roberts Optical robopt@execpc.com ~~~~~~~~~~~~~~~~~~ "An expert is a person who has made all the mistakes that can be made in a very narrow field." - Niels Bohr If hes only -2.25 he could forgo glasses for the computer if he sits a foot and a half from the monitor. If this is too close, he can get a weak pair of -1 glasses just for the computer and sit 32 inches away. Thats what I do, use a seperate pair for the computer I can read the computer that I'm working at if I take my glasses off. Frequently, I have to look at associates' work on the screen while looking over their shoulder. This is the distance at which I have a problem. I can't read the screen with or without glasses. I would guess it's probably a distance of about three feet. Then move closer to their screen so you can see without glasses > Then move closer to their screen so you can see without glasses Close working distances are known to accelerate myopia. -MT Only with a minus lens or getting closer than your natural near point. If someone is -2.25 and sits 45cm or further away, he uses up no accomodation and doesnt strain the eyes. Its like optical infinity for his eyes. >Only with a minus lens or getting closer than your natural near point. >If someone is -2.25 and sits 45cm or further away, he uses up no >accomodation and doesnt strain the eyes. Its like optical infinity for >his eyes. Why not simply get BI-focals -- bottom for the computer screen, top for distance. "Executive" type of bifocals: the "line" being uncurved, going straight across the lens. Thus you look far left and far right by swivelling (sp?) the EYEBALLS (ie, easy! fast!!), rather than with progressives, where you have to swivel your HEAD. Also, with BIG computer screens getting cheaper day by day, you want a WIDE "sweet-area" (ie in-focus area), and the widest you can get is from edge to edge of each lens, thus the need for "executive"-style bifocals. Trifocals? Near, mid (ie computer), far? Problem is that that mid section is by far the smallest of the three, not high enough to see all of a 20inch screen at one time. This presbyopia -- there ain't no free lunch. If your own inside-the-eye lens will no longer easily change shape (ie curvature, ie focus), then if you want things in focus, you need such a lens *outside* the eye. Wanting to glance fully left and right eliminates progressives (which enable you glance "up and down" eg a road you're sitting on, glance moving from your toes out along the road out to that distant semi heading towards you. Too bad that the geometry of surfaces works that way. David > Also, with BIG computer screens getting cheaper day by > day, [quoted text clipped - 6 lines] > smallest of the three, not high enough to see > all of a 20inch screen at one time. I don't think you can "focus" on the whole 20 inch screen at one time anyway, can you? While looking at a period in the center of the screen I can't read text 3 or 4 inches above or below it. It's well into "peripheral vision at that point. My 20" screen is 32" from my nose. At 32" just how big is that "sweet spot"? -Quick > > Also, with BIG computer screens getting cheaper day by > > day, [quoted text clipped - 12 lines] > 3 or 4 inches above or below it. It's well into "peripheral > vision at that point. My 20" screen is 32" from my nose. Still, if you have single vision glasses set for 32", you just move your eyes around. With trifocals or progressives with a tiny mid section, you have to move your whole head around. That gets old *really* fast, like in 10 minutes. There's no way I'd put up with that for long term use. I would probably get bifocals, with a very large upper area set for middle distance, and a small segment on the bottom for reading (I very often read printed materials while using the computer, at least for short times).  SignatureDan Abel dabel@sonic.net Petaluma, California, USA Yes I find it very comfortable to sit 45cm from the screen. It makes typing really easy. You are still stupid Ace. dr grant
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