Abstrait

Comparison of choroidal thickness in various grades of diabetic retinopathy to age matched control group using optical coherence tomography

Krishna Nagaradh, Mohan Kumar, Ashwini K, Sindhu Khanna

Purpose: To understand the variations in choroidal thickness in various stages of DR and compare that to control group using OCT.

Design: Prospective cross-sectional study

Methods: The present study sample included 200 eyes of 125 Type 2 DM patients, which also included 50 eyes of 25 patients in the control group without diabetes. Patients with macular oedema, high refractive error (>5D), fundus changes of glaucoma, previous retinal pathology treated with any kind of laser or anti VEGF, retinal pathologies like ERM, macular hole, vitreo macular traction, age related macular degeneration changes or any patient were a good OCT scan can't be taken due to hazy media are excluded from the study. DR was classified into five stages according to the Early Treatment Diabetic Retinopathy Study (ETDRS) classification. Choroidal thickness was measured using Enhanced-Depth Imaging (EDI-OCT) with a high- definition scan pattern. The measurements were made manually with a calliper in five positions (subfoveal, superior, inferior, nasal, and temporal to the fovea) and an average of all the five values is taken.

Results: SFCT was significantly lower in group NPDR (246.3 μm; p=0.04 versus control) as compared to both groups control and No DR. Even when SFCT was compared between control (mean SFCT=281.4 ± 23.6 microns) and proliferative diabetic retinopathy subjects (mean SFCT=242.3 ± 28.7 microns) a statistically significant subfoveal choroidal thinning was noted (p<0.0255). Eyes with DR had a significantly thinner subfoveal choroid than age-matched healthy eyes (p<0.03).

Conclusions: The choroidal thickness decreases with increase in severity of diabetic retinopathy. Diabetic choroidopathy is one of the pathology in progression of diabetic retinopathy and ultimately the visual prognosis in diabetic patients. Further larger studies with SS OCT and OCTA are needed to assess change in choroidal thickness and its impact on vision and retinal changes in diabetic patients.