Influence of phacoemulsification and intraocular lens implantation on the course of diabetic retinopathy.

PURPOSE: To study the effect of phacoemulsification and posterior chamber intraocular lens implantation on the course of diabetic retinopathy using the nonoperated fellow eye as a control. SETTING: Departments of Ophthalmology, Diabetes Center, Tokyo Women's Medical University, and University of Tokyo School of Medicine, Tokyo, Japan. METHODS: One eye of 66 diabetic patients who preoperatively had a similar stage of retinopathy in both eyes or no retinopathy bilaterally had cataract surgery. The course of diabetic retinopathy was followed for 1 year postoperatively. Patients were placed into 1 of 2 groups: Group A, progression of retinopathy in the operated eye was attributable to the surgical invasion (i.e., there was progression of retinopathy only in the operated eye or more progression in the operated eye than in the nonoperated fellow eye); Group B, no deterioration of retinopathy bilaterally, comparable level of deterioration in both eyes, or greater progression in the nonoperated eye than in the operated eye. RESULTS: Surgery resulted in retinopathy progression in 16 patients (24.2%, Group A): 13 with unilateral deterioration and 3 with greater progression in the operated than in the nonoperated fellow eye. Of the remaining 50 patients (75.8%, Group B), 39 presented no significant progression in either eye, 8 had bilaterally comparable progression, and 3 showed progression in the nonoperated fellow eye only. Retinopathy worsened in the operated eye in 24 cases (36.3%); of these, changes in 16 patients were attributed to surgical influence. There was no significant difference between Groups A and B in age, diabetes mellitus duration, diabetes treatment method, and preoperative and postoperative hemoglobin A1c levels. The distribution of preoperative retinopathy stage significantly differed between groups, with more patients without retinopathy in Group A and more patients with advanced retinopathy in Group B. CONCLUSION: Factors such as age, diabetes mellitus duration, diabetes treatment method, and hemoglobin A1c level did not affect the progression of retinopathy; however, preoperative status of retinopathy may influence the susceptibility of the retinopathy to surgical invasion. A considerable proportion of eyes with aggravation of retinopathy would reflect the natural course of the disease, systemic factors, or both rather than the influence of cataract surgery.