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An eye chart is a chart used to measure visual acuity comprising lines of optotypes in ranges of sizes. Optotypes are the letters or symbols shown on an eye chart. Learn about the history, types, and procedure of eye charts.
A LogMAR chart is a chart of letters used to estimate visual acuity, with each letter having a score value of 0.02 log units. The chart was designed to enable more accurate estimates than other charts, such as the Snellen chart, and has a standardized test task.
A Snellen chart is an eye chart that can be used to measure visual acuity by reading letters of different sizes. The chart is named after Herman Snellen, who developed it in 1862, and it is used to express vision as a fraction, such as 6/6 or 20/20.
Visual acuity is the clarity of vision and the ability to recognize small details. It is measured by optotypes on a chart and expressed as a fraction, such as 6/6 or 20/20, which means the distance at which a person with normal vision can see the same optotype.
Behind-the-ear or inner ear designs are typically more discreet, though earbud or one-piece styles may be more accessible for someone with poor vision or dexterity issues such as arthritis, says ...
The global burden of diabetic retinopathy increased dramatically from 1990 to 2015—from 1.4 million to 2.6 million people with visual impairment; from 0.2 million to 0.4 million blinded—due in large part to the increasing burden of type 2 diabetes in low- and middle-income countries. [57]
Problems with language, such as forgetting words, using incorrect words (calling the stove “the cooking thing”), or difficulty tracking a conversation. Disorientation. Losing or misplacing items.
Visual impairment is the partial or total inability of visual perception, which may be caused by various conditions or problems in the eye or brain. Learn about the symptoms, complications, treatment, and prevalence of visual impairment, as well as the different categories and definitions used by WHO and other countries.