Does cataract surgery yield good visual outcomes in diabetes patients?

"Factors associated with visual outcome included diabetic retinopathy and preoperative visual acuity (VA), but not HbA1C, emphasizing that systemic parameters may not be as valuable as certain ocular measures that may help evaluate visual potential," Debora Lee and the research team from the USA wrote in their study.

Diabetes patients are at an increased risk of cataract development and subsequent requirement for cataract surgery. Cataract extraction is the most commonly performed ambulatory procedure, and its incidence continues to rise. Also, there has been a rise in the prevalence of diabetes mellitus. However, in older publications, the visual outcomes following cataract surgery were shown to be less favourable in diabetes presence. Commonly cited reasons for worse results were pre-existing macular oedema and diabetic retinopathy.

There have been significant developments in cataract surgery, the management of diabetes and the treatment of diabetic retinopathy. Newer surgical techniques are associated with improved postoperative outcomes. Modern laser treatments and superior imaging modalities have enhanced the management of diabetic retinopathy. Recommendations for tight blood pressure and blood sugar control have reduced the risk of diabetic complications. These advancements may have improved the potential for favourable visual outcomes after cataract surgery in diabetes patients. However, not many large-scale studies have assessed the visual outcomes of diabetes patients after cataract surgery.

Against the above background, the research team aimed to investigate visual acuity outcomes of cataract surgery and factors linked with good visual outcomes among the diabetic population.

For this purpose, the authors conducted a retrospective case-control study of type 2 diabetes patients enrolled in the ACCORD (The Action to Control Cardiovascular Risk in Diabetes) study and ACCORD-eye substudy. The study included 1136 eyes of 784 participants of the ACCORD study who received cataract surgery during follow-up. Three hundred sixty-two eyes out of these had fundus photographs gradable for diabetic retinopathy. The primary outcome measure was the achievement of postoperative visual acuity of 20/40 or better.

The study led to the following findings:

• In the sample of 1136 eyes, 67.1% of eyes attained a good visual outcome of 20/40 or better.
• Factors predictive of good visual outcome were a greater educational attainment level (college compared to some high school, OR 2.35), bilateral cataract surgery (OR 1.55) and preoperative visual acuity (20/20 or better versus worse than 20/200, OR 10.59).
• Factors not significantly associated included sex, age, blood pressure, race, smoking, diabetes duration, lipid levels and haemoglobin A1C (HbA1C).
• In the subsample of 362 eyes, the absence of diabetic retinopathy was linked with good visual outcomes (OR 1.73).

"Two-thirds of eyes among patients with diabetes attained a good visual outcome of 20/40 or better following cataract surgery," the researchers wrote. "This rate remained similar to earlier reports and lower than the general population despite new guidelines and medical developments."

"Although the current visual prognosis following cataract surgery is usually suitable, still, certain factors limit the visual potential in diabetes patients, and continued efforts are necessary to improve visual outcomes," they concluded.

Reference:

Lee D, Agron E, Keenan T On behalf of the ACCORD Eye Study Research Group, et alVisual acuity outcomes after cataract surgery in type 2 diabetes: the Action to Control Cardiovascular Risk in Diabetes (ACCORD) studyBritish Journal of Ophthalmology 2022;106:1496-1502.