People with type 2 diabetes are more likely to develop diabetic retinopathy (DR) after cataract surgery, according a new population-based study. Over six years of follow-up, the adjusted risk of retinopathy was 1.7 times higher in diabetic patients who had undergone cataract removal, Dr. Ching-Yu Cheng of the Singapore Eye Research Institute and colleagues report in JAMA Network Open. "First, before cataract surgery, patients with diabetes but without DR should be informed about the higher risk of developing DR after cataract surgery," Dr. Cheng told Reuters Health by email. "Second, patients are to be recommended for careful and perhaps more frequent DR post-operative monitoring after cataract surgery." People with diabetes are more likely to develop cataracts, in addition to being at risk of DR, Dr. Cheng and colleagues note in their report. Cataract surgery can also worsen existing DR, they add. To better understand the risk associated with cataract surgery in patients with diabetes but no retinopathy, they conducted a prospective study in 972 Singapore Epidemiology of Eye Diseases Study participants, including 1,734 eyes. At baseline, 163 eyes had been treated with cataract surgery. During six years of follow-up, 187 additional eyes underwent cataract surgery. Out of the total of 350 eyes that received cataract surgery, 22% developed DR, compared to 14.1% of the 1,384 eyes that did not undergo cataract surgery. Adjusting for age, sex, ethnicity, diabetes duration and several other factors, the researchers found a relative DR risk of 1.70 in patients who had cataract surgery. Previous research has shown that cataract surgery can impair retinal blood flow and disrupt the blood-aqueous barrier, Dr. Cheng and colleagues note, while higher levels of inflammatory proteins have been identified in the aqueous humors after cataract surgery. "Taken together, it is plausible that these factors may collectively be associated with the development of DR after cataract surgery," they write. The findings "reinforce the concept that patients with diabetes with cataract should have adequate control of their systemic risk factors, including tight glucose and blood pressure control, prior to consideration of cataract surgery," Dr. Cheng said. "We are also studying whether after cataract surgery patients with DR progress faster and whether those without diabetic macular edema (DME) develop DME earlier," the researcher added, noting that it would also be interesting to investigate if the duration of cataract extraction or any complications would affect DR development or progression. Source
