Behavior of visual acuity, visual fields and contrast sensitivity in simulated cataract

Visual acuity, contrast sensitivity, and visual fields were examined with and without occluders both in a group of healthy subjects and in a group of patients with field defects (mostly caused by glaucoma). The various results were compared with one another as well as with the results obtained from a group of cataract patients examined before and after surgery. The results confirm clinical experience: visual acuity enables some conclusions to be drawn on the degree and progression of opacity of a lens. The changes in contrast sensitivity and in the visual field, however, represent rather the quality of the visual degradation. Contrast sensitivity and diffuse alterations in the visual field have similar progression patterns. The alterations in contrast sensitivity are more pronounced at higher frequency levels. The contrast sensitivity test can be recommended as a simple and complementary functional test, particularly on cataract patients with severe complaints and relatively good visual acuity. The results of occlusive experiments afford some practical conclusions which enhance knowledge and differentiation of visual field changes induced by cataract and glaucoma. These conclusions can provide a basis for further and more detailed investigations.