Journal of Clinical and Experimental Ophthalmology
Open Access

Abstract

Identifying Local Structural and Optical Derangement in the Neural Retina of Individuals with Type 1 Diabetes

Delia DeBuc, Erika Tatrai, Lenke Laurik, Boglarka Eniko Varga, Veronika Olvedy, Aniko Somogyi, William E. Smiddy and Gabor Mark Somfai

Background: To identify local structural and optical derangement in the neural retina of individuals with type 1 diabetes having early diabetic retinopathy (DR) and compare with healthy non-diabetic controls and type 1 diabetic individuals having no DR.
Methods: Optical coherence tomography (TDOCT) examination was performed on a total of 74 healthy eyes, 38 eyes with type 1 diabetes mellitus (DM) with no retinopathy and 43 eyes with mild DR (MDR). A total of 6 intraretinal layers were segmented on OCT images. Thickness and reflectance-based measurements were extracted for each OCT scan using features measured locally for each intraretinal layer.
Results: In the analysis where local measures were averaged in the separated macular regions outside the foveola, the mean thickness values of the outer segment of photoreceptors (OS) in the perifoveal region, ganglion cell and inner plexiform layer (GCL+IPL) complex in the parafoveal and outer plexiform layer (OPL) in the foveal region were significantly smaller (13%, 8% and 36%; respectively, p<0.001) when comparing MDR eyes with controls. The mean thickness values of the OPL (foveal region, 27%, p<0.001) and the OS (parafoveal (24%) and perifoveal (23%), p<0.001) were significantly smaller when comparing MDR with DM eyes. The reflectance-based measures were significantly smaller for all layers in MDR eyes compared with healthy and DM eyes (7-36%, p<0.001).
Conclusions: Our results show OCT is capable of detecting selective layer thinning and that the optical properties extracted from OCT images add significant evidence to the morphological information directly provided by OCT. It also suggests that the outer segment of the photoreceptor layer may be vulnerable in both type 1 diabetic individuals with and without early DR. Our results might also indicate that an early sign of vascular alteration development could be detected by investigating the changes in optical properties and thickness of the OPL.