The quantitative measurements of choroidal thickness and volume in diabetic retinopathy using optical coherence tomography and optical coherence tomography angiography; correlation with vision and foveal avascular zone

Abstract

Background To represent choroidal thickness (CT) and choroidal volume (CV) databases in diabetic retinopathy (DR) patients and healthy control participants using optical coherence tomography (OCT) and enhanced depth imaging OCT (EDI-OCT). No study had evaluated CT at all main stages of diabetic retinopathy in a single study. Methods The study included 176 eyes from 93 patients (39–80 years old; 42% females) who were divided into three groups based on DR severity and normal control group: 39 eyes no DR, 64 eyes NPDR, 33 eyes PDR, and 40 eyes normal control. The CT and CV were measured and statistically analyzed. Intra-observer and inter-observer coefficients of repeatability were calculated. Results Subfoveal CT showed persistent thinning from normal group (322.50 ± 69.24) to no-diabetic retinopathy (NDR, 308.33 ± 74.45) to nonproliferative diabetic retinopathy (NPDR, 283.45 ± 56.50) group and then thickening as the patient progressed to proliferative diabetic retinopathy (PDR, 295.17 ± 95.69) (P = 0.087). A significant difference was found between the control group and the NDR, NPDR, and PDR groups in nearly all CT and CV of Early Treatment Diabetic Retinopathy Study macular subfields. Fasting blood sugar (FBS = 189.08 ± 51.3 mg/dl) and diabetes mellitus (DM) duration (13.6 ± 6.5 years) had no noticeable effect on CT. In patients with diabetes, the best-corrected visual acuity (BCVA), diabetic macular edema (DME), and foveal avascular zone (FAZ) were not affected by CT and CV. Conclusions The choroidal thickness decreases from the early stages of diabetic retinopathy up to the NPDR stage, with a subsequent modest rise in CT during the PDR stage. There was no correlation between FBS, diabetes duration, BCVA, DME, and FAZ, and CT.

Comparison of Subfoveal Choroidal Thickness Values with Severity of Diabetic Retinopathy in Type 2 Diabetes Mellitus Patients

“…In another study, SCT examination using EDI-OCT and foveal avascular zone using OCTA. Although the results of the study did not find a correlation between SCT and the foveal avascular zone, this study has shown a new method to determine the association of SCT changes in patients with type 2 DM 21.…”

Choroidal Assessment in Patients with Type 2 Diabetes Mellitus and Non-Proliferative Diabetic Retinopathy by Swept-Source Ocular Coherence Tomography and Image Binarization

“…CT is used as a surrogate biomarker for the evaluation of choroidal vascularization, but it cannot indicate the affected choroidal component [ 50 ]. Agrawal et al defined the ratio between LA and TCA as CVI [ 25 ].…”

The Development and Clinical Application of Innovative Optical Ophthalmic Imaging Techniques

“…The OCT-A can be utilized for conditions involving vascular damage or choroidal neovascularization (CNV) (25). Apart from allowing the subjective identification of vascular abnormalities, OCT-A can also provide quantitative data (vessel density, blood flow, and foveal avascular zone size) that could be employed as vascular biomarkers (27)(28)(29)(30)(31)(32).…”