Contrast sensitivity is the reciprocal of the contrast at threshold, i.e., one divided by the lowest contrast at which forms or lines can be rec-ognized. If a person can see details at very low contrast, his or her contrast sensi-tivity is high and vice versa.
The Hamilton–Veale contrast sensitivity chart has 8 lines of 4 letters. The letters are grouped in pairs. The 2 letters on the left have a greater contrast than the 2 letters on the right of the same line. Read letters across left to right and down the lines.
Test Right and Left eye using either Chart 1 or Chart 2. Binocular scores are not recorded. Distance of 1 meter (39.5 inches) from participant. Luminance of white areas in each corner and center of chart from 18.4 fc – 36.9 fc. Test performance with trial frames containing participant distance refraction plus +0.75 diopters for 1 meter testing.
#5013 Near Peli-Robson Contrast Sensitivity Chart Features Traditional Sloan Optotypes found in the Original Pelli Robson Chart 1 For use at 16 in (40 cm) Includes three charts, each of which is scrambled to avoid memorization. The three charts may also be administered utilizing right eye, left eye and both eyes.
Pelli-Robson Contrast Sensitivity Chart. The above log contrast sensitivities are correct to within ±0.05 at the time of calibration of the chart. Copyright ©2013 Denis Pelli, John
The Mars Letter Contrast Sensitivity Test is a set of charts for testing peak visual contrast sensitivity. While the more famil-iar visual acuity test assesses resolution of the eye and visual system and the processing of high retinal image spatial frequencies, this test instead assesses processing of relatively low retinal spatial frequencies.
d) Log contrast sensitivity. For a chart of this kind, contrast is best defined as the difference in luminance between the letter and background, divided by the luminance of the background. This ratio of luminance, known as the Weber contrast, should not be confused with Michelson contrast, which is a different luminance
differences in grating contrast sensitivity within the normal range over different grating sizes that can effect their visual capability. Differences in seeing letters, aircraft silhouettes, faces and head-up
Quick Instructions: Instruct patient to read letters left to right for each line, from top to bottom of the chart. Mark misses with an “X.” Terminate test on 2 consecutive misses. Important: Allow only the letters C D H K N O R S V Z as responses.
Pelli-Robson Contrast Sensitivity Charts. These charts cover ¾ of the original contrast range and are manufactured to the same true log steps and use the same letters and letter sizes as the originals. Trans-illumination has the advantage of uniform fixed illumination and eliminates the need for staging the room and verifying chart luminance with