Contrast sensitivity measurement in retinal diseases by laser generated sinusoidal grating.

The contrast sensitivity function (CSF) of 83 patients with retinal diseases was measured by laser-generated sinusoidal grating pattern, which enables the direct measurement of the CSF between the retina and the brain. The CSF abnormality in various retinal diseases was not specific to each disease, and the severity may determine the pattern. The abnormal patterns and rough correlation with visual acuity (V.A.) are: (1) attenuation at high frequency ranges (V.A. greater than 0.8), (2) attenuation at intermediate and high frequency ranges (0.4 less than V.A. less than 0.7), (3) attenuation at all frequency ranges (V.A. less than 0.3). Some cases, however, showed discrepancy between visual acuity and CSF. At the recovery stage of central serous retinopathy and retinal branch vein occlusion, CSF showed delayed recovery or attenuated sensitivity even when visual acuity was restored to 1.0 or more. In retinitis pigmentosa and pre-retinal macular fibrosis, CSF showed more sensitive detection of abnormal macular function than visual acuity measurement. At the post-corticosteroid therapy of Harada's disease and Sympathetic Ophthalmia, CSF recovered more rapidly than visual acuity when retinal detachment was absorbed. Those discrepancies suggest that CSF measurement may be useful for evaluating progression or regression of these diseases.