Research Article

Effect of Xenon Arc and Argon Laser Photocoagulation on Time to Blindness in Diabetic Retinopathy: A Survival Analysis of Paired- Eye Data

Abstract

Background: Diabetic retinopathy is a leading cause of preventable blindness in adults of working age. Laser photocoagulation became the standard treatment after the Diabetic Retinopathy Study. Aim: To measure the effect of laser treatment on the time to blindness and to compare xenon arc with argon laser. Methods: The source dataset covers 200 patients. One eye of each patient was treated with laser and the other eye was left untreated. Blindness was defined as visual acuity below 5/200 on two consecutive visits. Survival was estimated with the Kaplan Meier method, compared with a log rank test within patients, and modelled with Cox regression. Results: Blindness occurred in 56 treated eyes (28.0%) and 101 untreated eyes (50.5%). At 48 months, 70.2% of treated eyes and 47.9% of untreated eyes were free of blindness. The hazard ratio for treated against untreated eyes was 0.41 (95% CI 0.28 to 0.59). The effect was larger in adult onset diabetes (HR 0.21) than in juvenile onset diabetes (HR 0.62). Xenon and argon gave similar results. Conclusion: Laser treatment roughly halved the hazard of blindness in this sample, with both laser types. The larger effect in adult onset diabetes needs confirmation. 

Authors affiliation:

Amer S. Al-Khafagi: Babylon Education Directorate, Iraq.

How To Cite: A.S. Al-Khafagi. Effect of Xenon Arc and Argon Laser Photocoagulation on Time to Blindness in Diabetic Retinopathy: A Survival Analysis of Paired-Eye Data. Healthcare Issues, 5(2):67–73, 2026. https://doi.org/10.58614/hi5210