Spectral OCT Angiography in the Assessment of Biomarkers of Diabetic Macular Edema in Navigation Laser Treatment

Abstract

Purpose — to study visualized biomarkers before and after navigation laser treatment in patients with diabetic macular edema (DMO) using optical coherence tomography-angiography (OCT-A).Methods. 85 patients (85 eyes) with focal DMO were under observation. The patients were divided into two groups, depending on the method of laser treatment used: group 1 consisted of 50 patients (50 eyes) who underwent navigation sub-threshold laser exposure in micro-pulse and continuous modes with individual selection of energy parameters according to the developed technology (patent RF for invention No. 2752544 of 27.01.2021), in group 2 (35 patients, 35 eyes) laser coagulation was performed according to the type of “modified grid”. The treatment was carried out on the NAVILAS 577S navigation laser system (“OD-OS”, Germany). All patients in both groups underwent high-resolution OCT-A according to the Angio Retina 3×3 mm and HD Angio Retina 6×6 mm protocol. The following biomarkers were evaluated by the OCT-A method: vascular density of the superficial vascular plexus (SCP), deep vascular complex (DCP); the number of microaneurysms and hyperreflective points; the area of the foveal avascular zone, as well as cysts and zones of disorganization of the inner layers of the retina (DRIL), at various times before and after (1, 3 and 6 months) treatment.Results. According to OCT-A, as a result of treatment in group 1, there was an increase in total vascular density from 38.45 ± 0.4 % to 44.85 ± 0.66 % in SCP and from 43.55 ± 0.38 % to 44.85 ± 0.66 % in DCP by 6 months of follow–up. In group 2, the total vascular density in SCP increased from 37.4 ± 0.36 % to 37.85 ± 0.34 %, in DCP from 43.35 ± 0.38 % to 44.05 ± 0.41 %. The number of microaneurysms decreased on average from 12 ± 0.42 to 9 ± 0.3 by 3 months and 7.5 ± 0.26 by 6 months in group 1 and, from 19 ± 0.7 to 15.5 ± 0.6 (3 months) and 13 ± 0.5 (6 months) — in group 2. The number of hyperreflective points decreased in terms of 3 and 6 months in both groups. The area of cysts progressively decreased, and the area of FAZ and DRILS was stable throughout all the follow-up period.Conclusion. OCT-A is a highly informative diagnostic method that allows noninvasively to identify visualized OCT-A biomarkers, as well as to evaluate the effectiveness of navigation laser exposure in patients with diabetic maculopathy with focal diabetic macular edema.