Choroidal thickness in type 2 diabetic patients with various stages of diabetic macular edema and retinopathy: A prospective study from central India

Abstract

Background: The objective of this study is to assess the changes in choroidal thickness in patients with type 2 diabetes with diabetic macular edema (DME) and diabetic retinopathy (DR), using enhanced-depth imaging (EDI) spectral domain optical coherence tomography (OCT). Materials and Methods: A total of 164 eyes from 104 patients were divided into no DR, DR without DME, and DR with DME. Eyes were also divided according to subtypes of DME. Subfoveal choroidal thickness (SFChT) and parafoveal choroidal thickness (PFChT) at 500 μm, 1000 μm and 1500 μm were measured using EDI-OCT and compared across groups. Results: A sample of 104 patients with diabetes consisted of 28 females and 76 males. The adjusted mean SFChT was 266.1 ± 42.40 μm in no DR eyes, 258.32 ± 39.52 μm in DR without DME eyes, and 246.11 ± 35.42 μm in DR with DME eyes (P = 0.028). The adjusted mean SFChT was 242.5 ± 33.04 μm in spongy edema eyes, 242.05 ± 39.73 μm in cystic edema eyes, and 247.9 ± 39.54 μm in serous retinal detachment eyes (P < 0.006). Conclusions: In eyes with DR, there is an overall thinning of the choroid on EDI-OCT. The subfoveal choroid was significantly thinner in eyes with DR and DME, specifically in cystic type of DME, as compared to those without DR. A decreased choroidal thickness may lead to tissue hypoxia and consequently increase the level of vascular endothelial growth factor, resulting in the breakdown of the blood-retinal barrier and development of macular edema.

Keywords

• Choroidal thickness
• diabetic macular edema
• nonproliferative diabetic retinopathy
• proliferative diabetic retinopathy