Abstract
Purpose :
Optical Coherence Tomography Angiography (OCTA) is a new diagnostic technology that can help us to a better understanding of diabetic retinopathy (DR) therefore validation of its results is needed.
We tested the hypothesis that DR severity is directly related with the vessel density (VD) and foveal avascular zone (FAZ) parameters measured with OCTA in a prospective observational study.
Methods :
We performed a comprehensive ophthalmic examination including best corrected visual acuity (BCVA), anterior and posterior slit-lamp biomicroscopy, retinography, OCTA with RS-3000 Advance AngioScan (Nidek, Gamagori, Japan) and microperimetry with MP-3 (Nidek, Gamagori, Japan) in diabetic mellitus and healthy subjects. Diabetic retinopathy severity was graded following the International clinical diabetic retinopathy disease severity scale.
Mean vessel density in the 4,5 x 4,5 mm centered in fovea protocol, FAZ area and FAZ perimeter were calculated and correlated with the DR severity. Also VD was calculated in smaller sectors (in a 9-grid-chart) and correlated with DR severity with Spearman correlation test.
Results :
Between healthy and diabetic retinopathy eyes, 210 eyes we analyzed. The severity of the DR was correlated with de mean vessel density in the superficial plexus with a strength of - 0,507 (95% CI=[(-0,601)-(-0,398)]; p<0,001) and in the deep plexus with a strength of - 0,606 (95% CI=[(-0,684)-(-0,512)] ; p<0,001). By sectors, in the superficial plexus the nasal superior and nasal inferior were correlated with higher strength than the other sectors. In the deep plexus, the most correlated sectors were temporal to fovea, central sector and nasal to fovea.
The severity of the DR was also correlated with de FAZ area and perimeter with a strength of 0,276 (95% CI=[0,146-0,396]; p<0,001) and 0,335 (95% CI=[0,189-0,464]; p<0,001), respectively.
Conclusions :
Diabetic retinopathy is a diabetic microvascular complication that can damage macular capillaries and perifoveal anastomotic arcades along the time. As a result, the vessel density is reduced in the macular area and FAZ area and perimeter are enlarged. This changes can be measured with OCTA and are more obvious as the severity of the DR increases.
Moreover, deep plexus is correlated with higher strength with the severity of the DR, as in previous studies is pointed, the injury of this plexus could be earlier and more severe.
This is a 2021 ARVO Annual Meeting abstract.