Abstract
Purpose :
Three-year evaluation and comparison in microvascular and neuronal macular parameters in patients with type 1 and 2 diabetes mellitus (DM1/DM2) and no clinical signs of diabetic retinopathy(DR).
Methods :
Ninety-two eyes/patients(20 with DM1, 48 with DM2, 24 healthy controls) were included in this prospective longitudinal study. Main inclusion criteria were: absence of any sign of DR in both eyes, good image quality. The right eye was chosen for analysis unless poor quality of imaging. OCT/OCT-angiography (OCT-A) images of the macula were taken using DRI swept source-OCT Triton plus. Following OCT parameters were evaluated: thickness of retinal nerve fiber layer(NFL), ganglion cell layer(GCL+) and NFL + GCL+ (GCL++). On 3x3 mm OCT-A images: foveal avascular zone(FAZ) parameters, perfusion/vessel density(PD/VD), fractal dimension(FD) at the superficial and deep capillary plexus (SCP/DCP); choriocapillaris flow voids(CC-FV) using MATLAB, version 2017b. Changes over time were evaluated by means of repeated measures ANOVA.
Results :
At baseline, in DM1 in the SCP a decrease in FAZ circularity index(CI, p<0.001), PD(p=0.05) and FD(p<0.001) vs controls was detected; in the DCP a decrease in FAZ CI and FD(p<0.001) and an increase in FAZ perimeter(p=0.03) vs controls; and in the CC a decrease in FV(p=0.02) vs DM2 were documented. In DM2, central subfield-GCL++ and GCL+ and inner ring-GCL+ thickness were reduced vs DM1(p≤0.01); in the SCP a decrease in FAZ CI and FD(p≤0.001) and an increase in FAZ area and perimeter(p≤0.01) vs controls were detected; in the DCP a decrease in FAZ CI and FD(p<0.001) vs controls and an increase in FAZ area and perimeter vs controls and DM1(p≤0.02) were detected. During the follow-up 14 eyes(20.6%) developed mild DR. After 3 years, no significant changes were observed in OCT parameters; FAZ area and perimeter in the DCP and FV(p<0.05 for all) significantly increased in DM2.
Conclusions :
Specific microvascular changes in SCP, DCP and CC were documented in both DM1&2 without clinical signs of DR.GCL thickness was more reduced in DM2 vs DM1. FAZ parameters in the DCP and FV in the CC significantly increased in DM2 in patients that progressed to mild DR vs those who remained stable(no clinical signs of DR).Further longitudinal studies should evaluate the role of DCP and CC in development of clinical signs of DR.
This is a 2021 ARVO Annual Meeting abstract.