Nearsightedness and Lens Power Question...?!
Question: Nearsightedness and Lens Power Question!.!.!.!?
This question assumes no astigmatism, just myopia!. What power lens "generally" corresponds what fractional value given to eyesight!? i!.e!. would a prescription of -0!.5 be equal to 20/30 vision!? Would a script of -1!.0 be equal to 20/40 vision!? Is there a doctor here who can tell me this or post a link to this information!? It's for a school project and I would like to know from -0!.5 to -5!.0 - Thanks in advance!. I'm only looking for myopia (negative) numbers but hyperopia (positive) numbers would also be interesting!. Is there a common mathematical formula to determin this information!?Www@Answer-Health@Com
Answers:
This is a rough rule of thumb!.!.!.!. for myopia, the amount of the prescription is roughly 0 to -0!.25 for each line on the chart!. For example, if you see 20/30 you might be -0!.50 or -0!.75, if you see 20/50, you might be -1!.00 to -1!.25!. Of course this does not have a linear progression!. The theory tends to fall apart at higher prescriptions!.
This link may help: http://forums!.studentdoctor!.net/showthre!.!.!.Www@Answer-Health@Com
This link may help: http://forums!.studentdoctor!.net/showthre!.!.!.Www@Answer-Health@Com
Well in the UK we certainly do not issue a predetermined prescription dependent on the visual acuity!. 6/6 or what you would call 20/20 vision is optimal for people to see!. You will gradually insert lens power until they reach this visual acuity!. Someone with -2!.00 shortsightedness could possibly see (uncorrected) 20/40 and so could someone who is -1!.00!. I'm not an optometrist myself but i have worked in optical practice for over 3 years and i have never heard of a mathematical formula!. Hope this is of some help to you!.Www@Answer-Health@Com