Session Title: Free Paper Session 2: Vascular Diseases & Diabetic Retinopathy I
Session Date/Time: Thursday 07/09/2017 | 09:00-10:30
Paper Time: 09:24
Venue: Room 117
First Author: : S.Vujosevic ITALY
Co Author(s): : A. Muraca M. Alkabes M. Lucchetti R. Torchio S. De Cilla'
To assess early modifications of inner retinal layer thickness and OCT-Angiography parameters in patients with diabetes mellitus (DM) Type 1 and Type 2 without clinical signs of diabetic retinopathy (DR).
Diabetic Retinopathy Clinic, University Hospital of Novara.
90 eyes of 90 subjects (60 patients of which 24 Type 1 and 36 Type 2 DM and 30 healthy controls) underwent complete ophthalmologic examination and colour fundus photo of the macula, spectral domain optical coherence tomography (SD-OCT) and OCT-Angiography (swept source OCT, DRI OCT Triton plus, Topcon Medical Systems Inc, Oakland, NJ, USA) performed on the same day. Major exclusion criteria were: any previous retinal treatment; cataract surgery within 6 months;any antiinflammatory/steroid topical treatment; refractive error > +6D; any stage of DR or diabetic macular edema; and significant media opacity that precluded good quality fundus imaging and examination. Following scan-patterns were performed on OCT: a linear B-scan(12mm length) centreed on the fovea at 0°; 3D Macula map covering central area of 7mmX7mm; and OCT-angiography maps covering central 3mmx3mm area and 6mmx6mm area. Retinal nerve fiber layer(NFL) and ganglion cell layer(GCL+) thickness were automatically determined by the instrument in the 1, 3 and 6 central milimeters. On OCT-Angiography, following quantitative and qualitative parameters were evaluated, by two graders independently (the area of foveal avascular zone(FAZ), number of microaneurysms, presence of regular or irregular FAZ, presence of capillary loss and presence of capillary network irregularities(tortuosity and/or beadings) in the superficial(SCP) and deep capillary plexuses(DCP).
NFL and GCL were thinner in the central 3mm in patients with DM Type 1 (114.9μm+1.7) versus controls (118.0μm+1.5, Bonferroni post-hoc test for multiple comparison, p<0.05) and versus patients with DM Type 2 (119.1μm+1.5, Bonferroni post-hoc test for multiple comparison, p<0.05), after adjusting for age. The area of FAZ was significantly larger: in patients with DM Type 1 versus controls in both SCP and DCP and in patients with DM Type 1 versus DM Type 2 only in DCP (p<0.05 for all); the number of microaneurysms was higher in patients with DM Type 1 versus controls in both SCP and DCP (p<0.01 for all); and in patients with DM type 2 versus controls only in DCP (p=0.0067). Logistic regression analysis showed greater association between all evaluated qualitative parameters in patients with DM type 1 and almost all (exception for capillary network irregularities in the SCP) for patients with DM type 2. The highest correlation was found between perifoveal capillary loss in the SCP and inner retinal thickness in patients with DM type 1 and Type 2.
Patients with Type 1 and Type 2 DM have specific neural and microvascular modifications even before clinical signs of DR. Patients with DM Type 1 had thinner perifoveal NFL and GCL thickness. Patients with DM Type 1 presented (all evaluated) microvascular abnormalities in both SCP and DCP, whereas in Type 2 DM mostly DCP was affected. In both Type 1 and Type 2 DM, the highest clinical correlation was found between inner retinal layer thickness and perifoveal capillary loss in the SCP. This data may help in better characterization of patients with DM and no clinical signs of DR.