Visual acuity is measured by a psychophysical procedure and as such relates the physical characteristics of a stimulus to a subject's percept and his/her resulting responses. Measurement can be by using an eye chart invented by Ferdinand Monoyer, by optical instruments, or by computerized tests like the FrACT.How to perform visual acuity test?
Usually measured at about 16 inches, it is a good way to measure your ability to cope with tasks such as reading or sewing. In most cases, near visual acuity is measured with both eyes open. You will be asked to hold a near point card at 16 inches and to read the smallest line possible.Is there a scale for visual acuity?
In the United States, the Snellen Eye Chart (pictured at left) is a test that ophthalmologists and optometrists use to measure a person's distance visual acuity. It contains rows of letters, numbers, or symbols printed in standardized graded sizes.What is corrected visual acuity?
Best corrected (with glasses) visual acuity guides the evaluation and management of almost every retina condition. Surgery is often performed or deferred based on vision. Visual acuity is the cornerstone of the ophthalmic examination. It measures central, or foveal, vision.