Extended targeted retinal photocoagulation versus conventional pan-retinal photocoagulation for proliferative diabetic retinopathy in a randomized clinical trial

Abstract

Purpose: To determine the clinical efficacy of extended targeted retinal photocoagulation (ETRP) compared to conventional panretinal photocoagulation (CPRP) in proliferative diabetic retinopathy (PDR).

Methods: In a single-masked randomized clinical trial, 270 eyes of 234 patients with naïve early or high-risk PDR were randomly assigned to receive either CPRP or ETRP (135 eyes, each treatment arm). Best-corrected visual acuity (BCVA) measurement, fundus examination, wide-field fluorescein angiography (WFFA) and optical coherence tomography were carried out before and 3 months after retinal photocoagulation. Primary outcome was early PDR regression, specified as reduction in retinal neovascularization based on WFFA at 3 months. Secondary outcomes were BCVA and central macular thickness (CMT) changes.

Results: There were significantly more high-risk PDR eyes in ETRP group compared to CPRP (109 and 94 eyes, respectively, P = 0.04). Early PDR regression occurred in 71.9 and 64.4% of eyes in the ETRP and CPRP groups, respectively (P = 0.19). The mean number of applied laser spots in the ETRP was significantly fewer than CPRP (1202 vs. 1360, respectively, P < 0.001). Mean BCVA at baseline and 3 months post-laser were 0.37 ± 0.26 and 0.47 ± 0.19 logMAR in the ETRP arm, respectively. In the CPRP arm these values were 0.40 ± 0.27 and 0.47 ± 0.24 logMAR, respectively. Although mean BCVA decreased significantly in both treatment arms (ETRP P < 0.001, CPRP P = 0.009), the difference was not significant between arms (P = 0.68). CMT increased significantly in both groups (ETRP 41.08 μm, P < 0.001, CPRP 33.31 μm, P < 0.001). Nevertheless, the difference between the groups was not significant (P = 0.26).

Conclusions: ETRP with fewer number of laser spots may be an appropriate alternative to CPRP in PDR regression at least through 3 months.

Gov registration number: NCT01232179.

Keywords: Extended targeted retinal photocoagulation; Panretinal photocoagulation; Proliferative diabetic retinopathy.