Light intensity and visual acuity following cataract surgery

The authors analyzed 310 cataract operations that were randomly distributed between two operating rooms, each containing a microscope with different light intensities. The light intensity of one microscope was almost threefold greater than the other. One hundred seventy-seven patients were excluded from this study because of medical or ocular problems that might affect visual acuity. The remaining 133 patients are the subjects of this paper. Seventy-one were operated upon under high intensity light, and 62 were subjected to lower illumination in the operating room. Visual acuity after operation was correlated with type of microscope, age, sex, method of cataract extraction, and use of intraocular lenses. Reduced visual acuity (20/40 or worse) was consistently more common with high intensity light and with increasing age. Further investigation is recommended to establish the cause of this reduced acuity.