{"id":1,"count":1,"description":"Standardised charts mean vision recording known as visual acuity can be more reliably verified.\r\n\r\nHowever, effects such as pupil size, contrast, optotype used, refractive error can cause variations.\r\n\r\nIf an observer has\u00a0 6\/6 visual acuity (or 20\/20 vision ) the 6\/6 size letters can be resolved at 6 metres (or 20 feet being 6 metres)\r\n\r\nThe direction of the E\u00a0 discriminated at different sizes is one type of eye test chart used in eyesight tests. The minimum angle of resolution is one minute of arc is \u2018normal\u2019 is by convention.\r\n\r\nAt this distance, the letters representing \u201cnormal\u201d or 6\/6(metres) or 20\/20(feet) acuity subtend an angle of five minutes of arc, and the thickness of the lines and of the spaces between the lines subtends one minute of arc.\r\n\r\neg 20\/40 or 6\/12 vision (being poorer vision than 6\/6 or 20\/20 ) means only the larger 6\/12 letter can be resolved at the 6-metre testing distance. Someone with so-called 6\/6 visual acuity could resolve the 6\/12 letter from a distance of 12 metres whereas\r\n20\/10 vision or 6\/3 vision (better vision) means the letter can be seen only at 3 metres by the 6\/6 limited person versus 6 metres for this better standard.","link":"https:\/\/www.peterdarcy.com.au\/category\/eye-acuity\/","name":"Eye Acuity","slug":"eye-acuity","taxonomy":"category","parent":0,"meta":[],"yoast_head":"\n