Contrast and glare sensitivity. Association with the type and severity of the cataract

Contrast and glare sensitivity tests are now being used as adjuncts to visual acuity in the assessment of visual function. Limited data are available on the associations of the former tests with cataract type and severity. The aim of the study is to assess these associations using standardized techniques.

Contrast sensitivity tests (using the Pelli-Robson chart) and glare sensitivity tests (using the Vistech MCT 8000) were done on 128 patients with cataracts and no other ocular disease and on 29 control volunteers. The cataracts were graded using the Lens Opacities Classification System II (LOCS II). Data from the left eyes were analyzed using logistic regression models.

Contrast sensitivity loss was associated with cataract severity for cortical (P less than 0.0001) and posterior subcapsular (P = 0.0001) cataracts and with decreased visual acuity (P = 0.0001). Night and day glare sensitivity were each associated only with increased severity of posterior subcapsular cataracts (P less than or equal to 0.003) and with decreased visual acuity (P less than 0.001). Additional analyses showed that contrast and glare sensitivity were similar in eyes with no cataracts and early cataracts.

These results suggest that the Pelli-Robson Chart and the Vistech MCT 8000 are good techniques for evaluating visual function in moderate to advanced cataracts. However, for early cataracts, other techniques need to be explored to assess visual function loss.