Cataract and diabetes
Modern-era study finds two-thirds of patients achieve good driving vision
Debora H Lee BS (left) and Emily Y Chew MD
A contemporary look at functional outcomes of cataract surgery in patients with diabetes showed that the majority attained good visual acuity (VA), reported researchers at the 2019 annual meeting of the Association for Research in Vision and Ophthalmology (ARVO).
To evaluate VA outcomes of patients with type 2 diabetes undergoing cataract surgery in the modern era, the investigators analysed data from 1,136 eyes of 784 participants in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) Study and the Follow-On (ACCORDION) Study. They found that postoperative VA of 20/40 or better was achieved by 762 (67.1%) eyes.
A logistic regression analysis was also conducted to identify factors associated with postoperative VA ≥20/40. Its results showed that preoperative VA and retinopathy were important predictors of the visual outcome.
“Historically, visual outcomes after cataract surgery have been reported as being less favourable in individuals with diabetes. The data we are reporting show that in the current world where patients with diabetes can achieve much better glycaemic control, a good proportion can achieve at least driving vision after cataract surgery. Clearly, however, the presence of diabetic retinopathy seems to be associated with poorer VA,” said Emily Y Chew MD, deputy clinical director, National Eye Institute, National Institutes of Health, Bethesda, Maryland, US.
Debora H Lee BS, Medical Research Scholar, National Institutes of Health, is lead author of the poster. She noted that compared with the research being presented, previous papers reporting good VA after cataract surgery in patients with diabetes included fewer patients who were operated on over earlier time periods.
“Subsequent to publication of these older studies, there have been a lot of advances in cataract surgery as well as in the management of diabetes and the management of diabetic eye disease. Therefore, we thought it was important to look at VA outcomes after cataract surgery in diabetics using a more recent cohort of patients,” she said.
Between 2001 and 2014, the ACCORD and ACCORDION studies followed 10,251 participants with type 2 diabetes at high risk for cardiovascular disease for a median of 9.2 years. Subjects returned for annually and had VA measurements done every two years using ETDRS charts. Cataract surgery was documented at the annual study visits. Eyes were eligible for inclusion in the analysis of cataract surgery functional outcomes if they had VA measurements within two years after surgery. The 784 patients in the study had a mean age of approximately 69 years at the time of cataract surgery, a mean haemoglobin A1C (HbA1C) of 8.3% and a mean diabetes duration of 16.3 years.
The logistic regression analysis of potential VA predictors found that in addition to preoperative VA and retinopathy, patient education level and having bilateral surgery were associated with the likelihood of achieving VA ≥20/40. Age at cataract surgery, sex, race, body mass index, smoking history, duration of diabetes, blood pressure, lipid levels and HbA1C level were not predictive factors.
“It is interesting to note that the VA outcome was not associated with HbA1C level in the regression analysis. Perhaps it is not the glycaemic control itself but rather the retinopathy as a consequence of poor glycaemic control that influences the potential VA outcome after cataract surgery,” said Ms Lee.
The main strength of the study is its size, she said. As a limitation, however, the data set lacked details about certain factors that could also be linked with VA outcomes. “We were able to extract complete data on demographic characteristics, but we lacked detailed data on such factors as the use of medications for controlling inflammation and preventing macular oedema,” she said.
“However, more comprehensive ophthalmic data, including fundus photograph gradings of diabetic retinopathy, are available for subjects enrolled in ACCORD-EYE, which is a prospective study of a subset of patients in ACCORD. We are planning to look at that information in more detail in the future.”