Evaluation of the macula and optic disc vascular parameters with optical coherens tomography angiography before and after laser of patients with planned laser treatment

Aim: To examine the effect of panretinal photocoagulation (PRP) with PASCAL® laser on macular and optic disc vascular parameters with optical coherence tomography angiography (OCTA) in very severe nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) cases. Materials and Methods: In this prospective study, 56 eyes of 56 patients diagnosed with very severe NPDR and PDR, who did not receive any treatment before admission, nor accept anti-VEGF injection or focal/micropulse laser therapy for the treatment of diabetic macular edema were included. PRP was applied to the patients in multi-scan mode, divided into 2 sessions and the total laser ablation area (LAA) was calculated for each patient. OCTA macula and optic disc extractions were performed at 30 minutes before laser treatment, 30 minutes after laser and 1st month follow-up. With OCTA, central macular thickness (CMT), subfoveal choroidal thickness (SFCT), foveal avascular zone (FAZ) metrics, superficial capillary plexus (SKP), deep capillary plexus (DKP) and radial peripapillary capillary plexus (RPCP) for small vessels (SV) and all vessels (AV) vascular density (VD) values were evaluated. Results: Severe NPDR was detected in 27 eyes and PDR was detected in 29 eyes. While there was a significant increase in CMT values in the 1st month after PRP, SFCT and best corrected visual acuity did not change. SKP-VD whole area, superior half, inferior half, parafovea and perifovea was found to be significantly lower than the baseline measurement at 30th min and 1 month after PRP. DKP-VD for whole area, superior half, inferior half, fovea, parafovea and perifovea was significantly lower 30th min after PRP but no significant difference was observed in the 1st month control compared to the baseline measurement. While there was no significant difference in PRP compared to pre-PRP in FAZ area and perimeter, the foveal density (FD-300) value was lower than basal values at 30 minutes after PRP. and 1st month. There was a significant decrease in RPCP-VD-AV intra-disc values, 30 minutes after PRP. A significant decrease was found in RPCP-VD-AV peripapillary values 1 month after PRP compared to pre-PRP. There was no relationship between LAA and changes in CMT, SFCT, OCTA macula and optic disc parameters. Conclusion: The effect of PRP on retina and optic disc microvascular structures can be detected with OCTA.