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Alaska Blind Child Discovery

A cooperative, charitable research project to vision screen every preschool Alaskan

Visual Acuity Screening

The fovea of the macula in the retina of a normal eye can discern tiny objects near or far in teh center of the visual field such an a letter "H" or "O" only 8 mm high at 6 meters yielding 20/20 or 6m/6m visual acuity. However, if the eye is blurred, out of focus, blocked, or neuro-retinal diseased, the visual acuity drops. Therefore Sensory Tests of the Visual Acuity right eye, left eye and both eyes is one of the most important of all eye screenings and tests. Adults and older children can READ letters or MATCH pictures to confirm what they see when the non-tested eye is patched to avoid peeking. Sophisticated methods, or expert observation is required to accurately measure visual acuity in infants and pre-verbal children. The letter, number or picture presented in specific large and small sizes at a specific distance are called "optotypes;" LEA and HOTV are recommended for children with matching cards. Tumbling E and Landholt C are technically the best. Adults are often screened with the ten Sloan letters ideally presented in the ETDRS format. Infant visual acuity is estimated at how well they change fixation or follow a small, moving object. Eye-N-Joy  
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Digital Values for Alpha Acuities        
Home Acuity Monitor and Screening        
Visual Acuity Tests        
Acuity Test Issues        
Amblyopia: child brain failed to learn        
ABCD Patches to avoid Peeking        


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