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

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).

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.

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).

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