What Is 20/20 or 6/6 Normal Vision?
In this short 35 second video Mr Glenn Carp explains what 20/20 and 6/6 mean
Mr Glenn Carp – “ The main concern of having 6/6 vision or 20/20 normal sight actually comes from whether you are based in the United Kingdom or you are based in America. It is truly precisely to do with feet and metres. 6/6 means you see at 6 metres what an median person can see at six metres, and 20/20 is the equivalent in feet, twenty dollar bill feet versus twenty feet. So the modal normal imagination in the general population would mean that what person sees at twenty dollar bill feet an average person can see. If you have better sight than 20/20 for model 20/16 it means that you can see at twenty feet what an average person can only see at sixteen feet and of run the opposite if you are 20/40, for example, it means you have poorer sight than an median person ; you see at twenty feet what they see at forty feet from much further away. ”
How you can achieve 20/20 or 6/6 normal vision or better
In the most coarse ocular acuteness test, an optometrist places an center chart at a standard distance, twenty feet, or six metres, depending on the customary unit of measure. At this distance, the symbols on the line representing “ convention ” acuteness on the eye chart, designated 20/20, is the smallest line that a person with convention acuteness can read at a distance of twenty dollar bill feet. It is potential to see better than the average, which optometrists express as ocular acuity of 20/16 or 20/12.5, or better. For example, 97 % of our short-sighted patients see 20/20 or better after operation ( which includes patients who see 20/16 or better, and patients who see 20/12.5 or better ).
Three lines above, the letters have twice the dimensions of those on the 20/20 line. The chart is at a outdistance of twenty dollar bill feet, but a person with convention acuity can read these letters at a distance of forty feet. This wrinkle is the ratio 20/40 ( or 6/12 ). If this is the smallest line a person can read, the person ’ randomness acuteness is 20/40, mean, in a identical harsh kind of way, that this person needs to approach to a distance of twenty dollar bill feet to read letters that a person with normal acuity could read at forty feet.
For example, 100% of London Vision Clinic patients (-1.00D to -9.00D) see 20/32 or better, and 100% of patients (+1.00D to +6.00D) see 20/40 or better after Laser Eye Surgery.
The biggest letter on an eye chart often represents an acuity of “ 20/200″, the measure that is “ legally blind. ” many people with refractive errors have the misconception that they have “ bad vision ” because they “ can not even read the E at the top of the chart without glasses. ” however, in most situations where acuteness ratios are mentioned, they refer to best-corrected acuity. many people with moderate myopia “ can not read the E ” without glasses, but have no problem reading the 20/20 credit line or 20/15 lineage with glasses. A legally blind person is one who can not read the E even with the best possible glasses. In Laser Eye Surgery, the surgeon ’ south goal is to get your vision without glasses after operating room to the like horizontal surface as your “ best-corrected ocular acuteness ” ( with glasses or contact lenses ) before operating room, or good. When optometrists or surgeons say “ advance or losing a lineage of vision ”, they mean the change in ability to read a tune on the eye chart without glasses after operating room, from the ability to read the line with glasses, before operating room .