Optical coherence tomography-guided selective focal laser photocoagulation: a novel laser protocol for diabetic macular edema

Abstract

BACKGROUND: To compare the anatomic and functional results between optical coherence tomography (OCT)-guided selective focal laser photocoagulation (OCT-laser) and conventional modified Early Treatment Diabetic Retinopathy Study (mETDRS) laser treatment for diabetic macular edema (DME).

METHODS: We analyzed treatment outcomes in 47 consecutive eyes treated with OCT-laser compared to 31 matched eyes treated with mETDRS. In the OCT-laser group, we identified 'significant actively-leaking microaneurysms on OCT' (SALMO) which are responsible for edema in OCT B-scan images, and thoroughly ablated them with photocoagulation. Best-corrected visual acuity (BCVA) and retinal thickness by OCT were compared at baseline and 12 months after treatment between two groups.

RESULTS: OCT-laser treatment resulted in significant improvements in BCVA, central subfield thickness (CST), and maximum retinal thickness (MRT) from baseline at 12 months from the time of therapy (+2.5 letter score, p = 0.04; -45.56 μm in CST, p < 0.001; -91.6 μm in MRT, p < 0.001). The mean number of treated 'SALMO' was 5.6 ± 4.0 (range 1-26), while the number of MAs in 'treatable lesions' by fluorescein angiography (FA) in the same eye was 16.3 ± 11.8 (range 2-42). There was no difference between OCT-laser and mETDRS groups in changes of these parameters from baseline at 12 months (p = 0.56, p = 0.89, p = 0.43 respectively). Fundus autofluorescence (FAF) and OCT revealed less tissue damage in OCT-laser-treated eyes, compared to eyes treated with mETDRS (p < 0.001).

CONCLUSIONS: OCT-laser shows similar anatomic and functional outcomes compared to conventional laser (modified ETDRS), with significantly less retinal damages.