The risk for developing vision-threatening retinopathy after cataract surgery in diabetic patients depends on the postoperative follow-up time.

PURPOSE

To identify parameters that can predict the postoperative risk for progression of retinopathy to a vision-threatening stage after cataract surgery. This may optimize the timing of surgery and the postoperative follow-up strategy in diabetic patients.

METHODS

Multi-state survival analysis with death as competing risk was used to investigate how year of onset and age of onset of diabetes, gender, body mass index, HbA1c and blood pressure had affected the risk for developing diabetic macular oedema (DME) and proliferative diabetic retinopathy (PDR) among 2540 right eyes from 2797 diabetic patients operated for cataract on one or both eyes during 25 years until July 1. 2019.

RESULTS

Cataract surgery had been performed in 98.8% of patients reaching 90 years of age. The risk for developing both DME and PDR was increased by cataract surgery. The risk was highest during the first postoperative years and increased by pre-operative variability in HbA1c. The risk after more than 20 years postoperatively increased by increased cumulative HbA1c pre-operatively. The other studied risk factors contributed differently to the development of the two complications.

CONCLUSIONS

Decision models for the timing of cataract surgery in diabetic patients should consider that the risk for developing vision-threatening retinopathy depends on follow-up time. Differences in the risk profiles for developing DME and PDR after cataract surgery support that the two complications should be regarded as separate late complications.