Corneal subbasal nerves changes in patients with diabetic retinopathy: an in vivo confocal study

¹ University of Milan, San Paolo Hospital, Eye Clinic, Milan, Italy
² IRCCS, G. B. Bietti Eye Foundation for the Study and Research in Ophthalmology, Rome, Italy

^* To whom correspondence should be addressed. E-mail: stefano_de_cilla{at}yahoo.co.uk.

	Abstract

PURPOSE: To study the subbasal corneal plexus (SCP) in patients with diabetic retinopathy (DR) treated or non-treated with panretinal Argon laser photocoagulation (ALP). METHOD: Fifty 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 evaluator. 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 according to the ETDRS classification. 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=0.01 and 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 and reflectivity were significantly lower in diabetic patients with proliferative diabetic retinopathy (PDR, respectively 2,0 ± 0,9 vs 2.9 ± 0,9, P=0.001, and 2,0 ± 0.8 vs 2.6 ± 0.7, P=0.003). Tortuosity was significantly higher in PDR group (2.2 ± 0.8 vs 2.8 ± 0.9, P=0.008). The PDR group treated with ALP had significantly lower subbasal nerves number as compared with non-treated patients (p=0,01). CONCLUSION: DR 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.

Key Words: subbasal corneal plexus, confocal microscopy, diabetic retinopathy, argon laser photocoagulation