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Medical Forum / General / Vision / August 2006Computer Vision system - optotype font
Hi all, I am a recently graduated ophthalmologist and I am trying to design a system for checking vision on a computer. There are several commercial designs - but they are quite expensive - $2000. I figured I could put something together myself and have played around with powerpoint and I think it will work. My question is this - is there are an "optotype" font or if not which font would work best. If true snellen letters are important for simple screening - should I design these myself and enlarge/minimize as appropriate - or are these available somewhere already. I hate to re-invent the wheel if I dont have to. Thanks in advance isaac J. Isaac Barthelow, M.D. North Valley Eye Care 114 Mission Ranch Blvd. #50 Chico, CA 95926 (530) 891-1900 fax: (530) 895-1531 www.northvalleyeyecare.com Dear Issac, There was a NEAT Snellen at this site: http://www.smbs.buffalo.edu/oph/ped/ivac/ivac.html It had a random Snellen -- with pictures and letters. Unfortunately it just went "down" last night. For quick verification of visual-acuity (that could not be "cheated") it was excellent. Best, Otis > Hi all, > [quoted text clipped - 20 lines] > fax: (530) 895-1531 > www.northvalleyeyecare.com Dear Issac, Here is a "Monitor" chart for your interest: http://www.eyecareindia.com/Files/DistanceTest.html Sincerely, Otis www.myopiafree.com +++++++++++++ > Dear Issac, > [quoted text clipped - 36 lines] > > fax: (530) 895-1531 > > www.northvalleyeyecare.com The IVAC Chart is back in service. For anyone who must do basic testing -- it is excellent since you can set it for 10 feet (when needed), and test from your monitor. Give it a try. If your eyes do not meet the required legal standard of the DMV, then you will need to see an OD to get a driver's license. Or clear that line by using "Bates" methods -- after the OD confrims you do not have a medical problem. Best, Otis > Dear Issac, > [quoted text clipped - 36 lines] > > fax: (530) 895-1531 > > www.northvalleyeyecare.com > For anyone who must do basic testing -- it is excellent > since you can set it for 10 feet (when needed), and > test from your monitor. Oh good, you've changed another testing standard. Give us a little time... sometimes it's hard for us to keep up with you. > Or clear that line by using "Bates" methods -- after > the OD confrims you do not have a medical > problem. Citing Bates confrims for us that you do not have much education. But by all means, continue instructing us. It's amusing. -MT Dear Mike, Your denial of Bates (and ALL SECOND-OPINION METHODS) suggests a lot of majority-opnion bias -- on your part. Here, as this poster requested, I suppled a "monitor" Snellen which would allow anone the ability to check his visual acuity at no cost. What a given person might do (assuming 20/50 vision) would depend on WHICH person he would consult. You and your majority-opinion or a second-opinion optometrist like Steve Leung at: www.chinamyopia.org Your denial of a competent second-opinion does not prove anything at all. Best, Otis > > For anyone who must do basic testing -- it is excellent > > since you can set it for 10 feet (when needed), and [quoted text clipped - 12 lines] > > -MT > Your denial of Bates (and ALL SECOND-OPINION METHODS) > suggests a lot of majority-opnion bias -- on your part. Supporting Bates tells us either you have not read his book, or you have no training in scientific method. Which is it? > Here, as this poster requested, I suppled a "monitor" Snellen > which would allow anone the ability to check his visual acuity > at no cost. And you could eliminate a lot more myopia by testing at 3 feet. > and your majority-opinion or a second-opinion > optometrist like Steve Leung at: Where in the world would I find another optometrist like Steve Leung? -MT Dear Mike, What I SUPPORT is a person's right to an INFORMED, COMPETENT SECOND-OPINION -- at the threshold of nearsighedness. Nearsighedness = a negative refractive STATE of the fundamental eye. (No desired, of course, but scientific reality.) The easy thing to do about threshold nearsighedness is NEGLECT. That is a matter for the parents and child to decide -- after they are informed of the proven behavior of all natural eyes. Prenvention is not easy -- but if down "correctly" it can be successful. Have a nice day, Otis > > Your denial of Bates (and ALL SECOND-OPINION METHODS) > > suggests a lot of majority-opnion bias -- on your part. [quoted text clipped - 14 lines] > > -MT > Prenvention is not easy -- but if down "correctly" it can be > successful. So you're fond of telling us. We'll all adopt your technique in a heartbeat as soon as you show us that it works. Until then, I'll stick with what I read in textbooks. -MT Of coure a strong minus works INSTANTLY, and impresses everyone -- in five minutes. Yes your mind is made up and your are stickin with it. And yes, the "plus" does not work "instantly" and must be WRONG for that reason. Yes, Mike, your logic is perfect. Have a great day, Otis > > Prenvention is not easy -- but if down "correctly" it can be > > successful. [quoted text clipped - 5 lines] > > -MT > And yes, the "plus" does not work "instantly" and must > be WRONG for that reason. So you CAN show us the evidence that it works, but you WON'T. Not very convincing, Otis. Find another windmill. -MT Dear Mike, Of course you can prove that the fundamental eye will "move positive" when you place a mild plus lens on it. You simply have to RESPECT the NATURAL EYE as a dynamic system. You take a primate eye with a refractive STATE of +2 diopters and place a +2 diopter lens on it. If the natural eye is a dynamic system -- it will change its refractive STATE in a positive direction. By about +1 diopter in one year. But wait, you insist that this DOES NOT HAPPEN IN THE NATURAL HUMAN EYE. But it does. Best, Otis +++++++++ Bogo> ophthalmologist prescribed glasses OD +2.25 (sphere) OS +1.75 (+0.25) and then advised us to patch him 2 hours a day, and do some manual activities while patched. We did this for 7 months, the amblyopia is gone for now. Both eyes are 20/30. Bogo> The doctor has raised the prescription twice, so in 8 months my son has needed 3 different prescriptions, why didn't the doctor go all the way since day one? Otis> I think he wanted to avoid having your son develop more hyperopia from the +2 diopter lenses. Bogo> Anyway, my son has been wearing the last prescription, 3.25 in both eyes, for 5 days now and we noticed today, as he was watching TV, that he still crosses his right eye. Otis> It is interesting that your son's eyes responded to a +2.00 diopter lens -- by chaning in a positive direction -- by +1.00 diopters in 8 months. Otis> This confirms the natural eye's responsiveness to an applied +2 diopter lens. Have a wonderful day, Otis > > And yes, the "plus" does not work "instantly" and must > > be WRONG for that reason. [quoted text clipped - 4 lines] > > -MT > You take a primate eye with a refractive STATE of +2 diopters > and place a +2 diopter lens on it. If the natural eye is > a dynamic system -- it will change its refractive > STATE in a positive direction. By about +1 diopter in > one year. If you believe hard enough, it just HAS to be true. -MT If you state your office fib (that the eye is not a dynamic system -- and proven to be so) then you will believe your office fib -- and not in science and scientific proof. Otis > > You take a primate eye with a refractive STATE of +2 diopters > > and place a +2 diopter lens on it. If the natural eye is [quoted text clipped - 5 lines] > > -MT > If you state your office fib (that the eye is not a dynamic > system -- and proven to be so) then you will > believe your office fib -- and not in science and > scientific proof. So "dynamic" means you can change the eye as you please. Must give you a powerful feeling. -MT > Until then, I'll stick with what I read in textbooks. Come on, Mike. ANYONE can read a textbook. ;)  SignatureScott Reverse name to reply Subject: Back on thread topic I am a recently graduated ophthalmologist and I am trying to design a system for checking vision on a computer. There are several commercial designs - but they are quite expensive - $2000. I figured I could put something together myself and have played around with powerpoint and I think it will work. If true snellen letters are important for simple screening - should I design these myself and enlarge/minimize as appropriate - or are these available somewhere already. I hate to re-invent the wheel if I dont have to. ++++++++++++ Otis> I supplied what Dr. Barthelow requested. A "monitor" eye-chart that could be used with: 1. Different differences -- down to 10 feet (or 3 meters). 2. Random letters (to prevent memorization). 3. Use of pictures (for children). 4. Simple to use. I did mention that plus-prevention is the second-opinion, but that is a "side" issue -- for the person who wishes to keep his vision clear for life (under HIS CONTROL) versus losing his vision to an over-prescribed minus -- and getting stair-case myopia from it. But that is a side issue. Best, Otis > > Until then, I'll stick with what I read in textbooks. > > Come on, Mike. ANYONE can read a textbook. ;) |
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