Subthreshold diode micropulse panretinal photocoagulation for proliferative diabetic retinopathy

To report the visual acuity and clinical outcomes of a pilot study of subthreshold diode micropulse (SDM) panretinal photocoagulation (PRP) for treatment of diabetic retinopathy.

A retrospective chart review of all patients undergoing PRP for diabetic retinopathy between April 2000 and February 2003 was performed. Treated conditions ranged from severe non-proliferative to severe proliferative diabetic retinopathy. An SDM PRP protocol designed to avoid detectable laser lesions was employed. Treatment failure end points included the development of vitreous haemorrhage or the performance of vitrectomy.

Ninety-nine eyes of 63 patients undergoing SDM PRP were identified. Median follow-up was 1.0 year (range of 0.3-2.7 years). Treatment sessions per eye ranged from 1 to 6 (with a median of two sessions per eye). Overall visual acuity remained unchanged. The probability of treatment failure end points at 12 months post-treatment was 12.5% for vitreous haemorrhage and 14.6% for vitrectomy (from Kaplan-Meier survival analysis). Age, sex, diabetes type, and baseline retinopathy status were not significantly associated with the risk of either failure event. No treatment complications were observed. No eye demonstrated any laser lesion detectable clinically or by fluorescein angiography postoperatively.

SDM pan retinal photocoagulation minimized retinal damage and treatment complications in the management of high-risk non proliferative and proliferative diabetic retinopathy. Visual loss was prevented with a low rate of vitreous haemorrhage and vitrectomy postoperatively. Further study of the safety, efficacy, and optimal treatment parameters of SDM pan retinal photocoagulation for diabetic retinopathy is warranted.