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Contrast Sensitivity
Contrast sensitivity testing is method used to
assess the quality of vision. It differs from typical visual acuity
testing in that it simulates "real-world" circumstances. Routine
visual acuity testing measures eyesight under best possible conditions. It
does not reflect the difficulties one might experience when driving at night, or
trying to read a sign on a cloudy, overcast afternoon.
The test is performed by showing the patient a
series of stripes or bars that slant in different directions. The patient
must identify which way each series of stripes is tilted. As the test
progresses, the bars become thinner and lighter. Patients with excellent
contrast sensitivity can determine the direction very light, thin bars are
slanted.
This is particularly useful for measuring visual acuity in patients who report difficulty with their vision, yet see well on the conventional eye chart.
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