Contrast sensitivity in different types of early lens opacities.

The purpose of the present study was to evaluate the relationship of various types of early lens opacities with contrast sensitivity at different spatial frequencies. The Lens Opacities Classification System II and Lensmeter 701 were used in the grading of the lens status. The contrast sensitivity was tested with the Vistech VCTS 6500 distance test with optimal correction of refractive errors. Data from 995 eyes were available for the present study. Contrast sensitivity decreased by increasing lens opacification graded with the Lens Opacities Classification System II and also by increasing Lensmeter 701 reading. When the statistical model was adjusted for age and best corrected visual acuity, nuclear opacities and nuclear colour were not associated with decreased contrast sensitivity, however, there was a weak, but statistically significant correlation between contrast sensitivity reduction and cortical opacities at high spatial frequencies, and between contrast sensitivity and posterior subcapsular opacities at low and medium spatial frequencies.