Measuring Contrast Sensitivity in Clinical Practice by Means of a New PsychoPhysical Computerized Test: VistaVision©

Measuring Contrast Sensitivity in Clinical Practice by Means of a New PsychoPhysical Computerized Test: VistaVision

For many years contrast sensitivity testing has been recognized to be an useful strategy to assess visual function in many ophthalmological diseases as glaucoma, optic neuropathies, amblyopia as well as in neurological and, recently, even psychiatric conditions.

So far as we know, available contrast sensitivity tests are performed by means of paper-made screens or backlighted windows and do not employ a psychophysical procedure to assess the exact threshold value for every tested spatial frequency.

The new VistaVision Contrast Sensibility Test (DMD Med Tech, Turin, Italy) is a computer-based psychophysical tool, using a particular staircase procedure to fit the psychometric function.

The exam evaluates spatial frequency ranging from 0.75 c/deg to 18 c/deg, widely covering the values processed by the magnocellular (under 1.3-2 c/deg, according to Legge,1978) and parvocellular ganglionar pathway.

Within this range, the VistaVision evaluates contrast sensitivity across six different spatial frequency values (0.75, 1.5, 3, 6, 12, 18 c/deg). Test distance is 3 meters. Subjects are presented sinewave gratings (mean luminance 120 cd/m2) in random order, each oriented along the vertical or tilted left/right side and are asked to report the orientation of the displayed grating by a remote control. For each spatial frequency value, threshold level is obtained by a 4-2 staircase procedure.

The difference between VV function and a 3-forced choice paradigm (3AFC) relies on the further possibility to answer "null" by clicking an appropriate button.X normal subjects aged x year (y) were recruited. Inclusion criteria were BVCA: 60/60, ametropy

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