Effects of Subthreshold Yellow Pattern Laser Treatment in Diabetic Macular Edema: Optical Coherence Tomography Angiography Study

PURPOSE: To assess the effects of subthreshold yellow pattern laser (SYPL) treatment in diabetic macular edema (DME) using optical coherence tomography angiography (OCTA).
METHODS: Thirty eyes of 30 diabetic patients diagnosed as naïve DME (central subfield thickness (CST) <400μm) between October 2018 and January 2020 at Ege University, Department of Ophthalmology were prospectively included in the study. Fovea sparing SYPL were performed to the macula. Comprehensive eye examination along with OCTA were performed at baseline, 1st month, and 3rd month of follow-up. Data during the follow-up were compared with the baseline.
RESULTS: The mean age of the patients (15 male, 15 female) was 63.7±6.7 (48-74) years. The mean diabetes duration was 17.9±5.4 (13-27) years; mean HbA1c was 6.6±0.5 (5.7-7.7) g/dL. Best-corrected visual acuity (BCVA) did not show significant change during the follow-up (p=0.698). CST measurements were 323.7±40.1 (262-393) μm, 316.8±40.9 (268-377) μm and 318.1±39.9 (226-396) μm at baseline, 1st, and 3rd month, respectively (p=0.591). On OCTA, mean vessel density (VD) in superficial capillary plexus (SCP) were 44.7±4.6 (37.4-52.3), 45.6±4.7 (38.6-54.9) and 44.6±3.9 (37.5-49.8); while mean VD in deep capillary plexus (DCP) were 43.1±4.8 (36.3-52.7), 45.3±4.8 (38.9-54.2) and 42.7±3.3 (37.4-49.3) at baseline, 1st, and 3rd month, respectively (p=0.383 and p=0.291). Foveal avascular zone (FAZ) area did not change significantly during the follow-up (p=0.998).
CONCLUSION: SYPL treatment in DME appears to be safe with no statistically significant difference in macular capillary perfusion, as well as no change in BCVA and CST during the 3 months of follow-up.