Corneal Confocal Microscopy in Patients With Diabetic Retinopathy

Purpose:to study the subbasal corneal plexus in patients with diabetic retinopathy (DR) treated or non-treated with panretinal Argon laser photocoagulation (ALP). Methods:50 consecutive patients with DR and 50 age- and sex-mached normal controls were examined using Heidelberg Retina Tomograph (HRT), Rostock Cornea Module (RCM) by a masked well trained evaluator. Intraobserver agreement for image scores was calculated by means of intraclass correlation coefficient (ICC= 0.70= substantial agreement).The following subbasal plexus nerves parameters were considered: number per frame , tortuosity and reflectivity. Diabetic patients were divided into two groups, according to the presence of proliferative vs non proliferative retinopathy (classification of the ETDRS). Results:number per frame and reflectivity were significantly lower in diabetic patients as compared with controls (2.4±1 vs 2.9±0.8, P=0.01and 2.3±0.9 vs 2.6±0.9, P=0.04 respectively). Tortuosity was significantly higher in diabetic patients (2.5±0.9 vs 2.0±0.8, P=0.002). Number per frame of SCP (respectively 2,0±0,9 vs 2.9±0,9, P=0.001) and reflectivity (respectively 2,0±0.8 vs 2.6±0.7, P=0.003) were significantly lower in diabetic patients with proliferative retinopathy as compared with non proliferative retinopathy. Tortuosity was significantly higher in diabetic patients with proliferative retinopathy (2.2±0.8 vs 2.8±0.9, P=0.008). In the group of proliferative DR, patients treated with ALP had significantly lower subbasal nerves number as compared with non-treated patients (p=0,01). Conclusions:diabetic retinopathy may induce remarkable changes in the SCP. There is a difference between proliferative and non proliferative retinopathy and in the former group between ALP treated and non-treated patients.