Eye Charts – How Do They Work
ps Natural Vision Improvement markets itself as a lifestyle method of improving eyesight by wholistic means
My son is 5 years old and has just had his first school eyesight test. We have been advised to take him to see an optician – which of course we will do but I just want to check what the following means.
The school test said that on the Snellen scale he is 6/6 (20/20) in his left eye and 6/9 (20/30) in his right eye. (This is in metric)
Can someone explain what this means and if it is anything to seriously worry about.
Herman Snellen, a Dutch ophthalmologist, designed the first eye chart, which measures visual acuity. Referred to as the Snellen Chart, it was developed in 1862 and is still used today. He set the baseline of measurement at 20 feet, the approximate distance at which light rays entering the eye are parallel and do not require our eyes to bend the rays to focus them upon the retina.Snellen set the standard of 20/20 (6/6 Metric) vision to represent “normal sight,” or what a person with normal vision could see at a distance of 20 feet. (Weber, Humphrey, and Silver, 1997)
This means that a person with 20/40 (6/12 Metric) vision must be 20 feet away to read what he or she should be able to read at 40 feet; a person with 20/85 vision must be 20 feet away to read what he or she should be able to read at 85 feet away, and so on.
This standard does not measure visual acuity at close distances. Similar charts were devised with smaller letters to read at close range for the measurement of near vision. Read the whole article here
Tags: Eye Charts
improve eyesight | SonjaHelga | 
August 22, 2007 7:00 am
![[Valid RSS]](http://www.ruthsinformationabout.com/valid-rss.png "Validate my RSS feed")
[...] see “eye charts, how do they work” article here Share and Enjoy:These icons link to social bookmarking sites where readers can [...]
[...] for easier reading check out my article on “Eye Charts, How Do They Work“ thanks to wikipedia! Share and Enjoy:These icons link to social bookmarking sites where [...]
[...] Improving Your Vision Naturally is a holistic approach to rebuilding your vision. [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care Share and Enjoy: These icons link to social bookmarking sites where readers can share and [...]
[...] Improving Your Vision Naturally is a holistic approach to rebuilding your vision. [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care Share and Enjoy: These icons link to social bookmarking sites where readers can share and [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care Share and Enjoy:These icons link to social bookmarking sites where readers can share and discover [...]
[...] Improving Your Vision Naturally is a holistic approach to vision therapy. [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care addthis_url = [...]
[...] Improving Your Vision Naturally is a holistic approach to vision care. [...]
[...] Improving Your Vision Naturally is a holistic approach to vision therapy. [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care Share and [...]
[...] Improving Your Vision Naturally is a holistic approach to vision care. [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] Improving Your Vision Naturally is a holistic approach to rebuilding your vision. [...]
[...] Improving Your Vision Naturally is a holistic approach to vision therapy. [...]
[...] Improving Your Vision Naturally is a holistic approach to vision therapy. [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] Improving Your Vision Naturally is a holistic approach to vision care. [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care Share and [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care addthis_url = [...]
[...] Improving Your Vision Naturally is a holistic approach to rebuilding your vision. [...]
[...] Vision Therapy can be the most important choice you make. Become pro-active in your eye care Natural Vision Therapy Will Improve Your Vision – Just See. [...]
[...] Improving Your Vision Naturally is a holistic approach to vision therapy. [...]
[...] Vision Therapy can be the most important choice you make. Become pro-active in your eye care Natural Vision Therapy Will Improve Your Vision – Just See. [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] Improving Your Vision Naturally is a holistic approach to vision care. [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] Improving Your Vision Naturally is a holistic approach to rebuilding your vision. [...]
[...] Improving Your Vision Naturally is a holistic approach to vision care. [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care Mail this post var UserClicked=false; document.onkeydown=spy; document.onmousedown=spy; [...]
[...] Improving Your Vision Naturally is a holistic approach to vision care. [...]
[...] Improving Your Vision Naturally is a holistic approach to vision therapy. [...]
[...] Improving Your Vision Naturally is a holistic approach to rebuilding your vision. [...]
[...] Vision Therapy can be the most important choice you make. Become pro-active in your eye care Natural Vision Therapy Will Improve Your Vision – Just See. [...]
[...] Improving Your Vision Naturally is a holistic approach to vision therapy. [...]
[...] Keep your eyes healthy for as long as you can. Become pro-active in your eye care [...]
[...] Vision Therapy can be the most important choice you make. Become pro-active in your eye care Natural Vision Therapy Will Improve Your Vision – Just See. [...]
[...] Vision Therapy can be the most important choice you make. Become pro-active in your eye care Natural Vision Therapy Will Improve Your Vision – Just See. [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care Mail this postPopularity: 3% [?]SHARETHIS.addEntry({ title: “Yourr Eyes Are So Important For [...]
[...] your eyes healthy for as long as you can. Become pro-active in your eye care Share and [...]
[...] Improving Your Vision Naturally is a holistic approach to rebuilding your vision. [...]
[...] Improving Your Vision Naturally is a holistic approach to vision care. [...]