Cataract Surgery in Diabetic Patients

Nearly all adults with diabetes who live long enough will develop vision-impairing cataracts, but decisions on surgical timing must consider the procedure’s benefits and risks in this patient population, according to Toke Bek DMSci.

“Cataract can obstruct the view to the retina, which argues for performing cataract surgery early to enable fundus examination for monitoring of diabetic retinopathy (DR),” Dr Bek explained. “On the other hand, cataract surgery leads to retinal swelling that may accelerate the development of maculopathy, and there is also evidence suggesting that cataract surgery can accelerate the development of proliferative diabetic retinopathy (PDR). These risks argue for postponing cataract surgery.”

To gain further insight to guide optimal timing of cataract surgery and postoperative follow-up duration in patients with diabetes, Dr Bek and colleagues undertook a study to identify how known risk factors for progression of DR affect postoperative risk for developing diabetic macular oedema (DMO) or PDR.¹

The research used clinical data from diabetic patients seen at the Aarhus University Hospital ophthalmology department over a 25-year period and survival analysis methodology that accounted for death as a competing risk for developing the vision-threatening complications postoperatively. Statistical analyses used to characterise risk for the two complications over time and the impact of different risk factors accounted for the finding that the hazards for both DMO and PDR were not proportional over time, Dr Bek explained.

Results showed that almost all patients (98.8%) who reached age 90 years underwent cataract surgery, which was associated with increased risk for developing both DMO and PDR. Cataract surgery increased the risk for DMO threefold overall (P < 0.0001). The risk varied over time—reaching its highest in the first 5 years postoperatively, falling between 5 and 20 years, and increasing thereafter—but was statistically significant during all three postoperative observation intervals.

Investigation of DMO risk factors confirmed a role for known predictors but also revealed that some factors had an impact immediately after surgery whereas others contributed to later development. The analysis of risk factors for PDR, which used different methodology, likewise revealed different factors impacted risk at different follow-up times after surgery.

Commenting on the clinical implications of the findings, Dr Bek said they make it very difficult to explain to patients their risk of developing DMO or PDR after cataract surgery.

“So, the take-home message might be that the timing of cataract surgery in patients with diabetes cannot be calculated in advance because the risks are difficult to estimate,” he said. “Therefore, the determination needs to be a clinical decision based on the patient’s subjective symptoms weighed against the clinician’s need for examining the fundus.”

Addressing the issue of how long to continue postoperative follow-up, Dr Bek said, “The fact that the risk of both DMO and PDR persisted for more than 20 years indicates that the recommendation to maintain vigilant control after cataract surgery in patients with diabetes may be relevant for a long time after the procedure.”

Dr Bek presented at EURETINA 2025 in Paris.

Toke Bek DMSci, MBA is Professor, Head Consultant, and Chair of the Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark. toke.bek@mail.tele.dk

1. Bek T, et al. Acta Ophthalmol, 2022; 100(3): e719–e725.