Changes in total and inner retinal layers in type 1 diabetes mellitus with no retinopathy measured by spectral domain and swept source technologies.

Author: Ismael Bakkali El Bakkali (Spain)

Co-authors: Guillermo Pérez Rivasés, Ana Boned Murillo, María Dolores Díaz Barreda, Isabel Bartolomé Sesé, Elvira Orduna Hospital, Isabel Pinilla Lozano

Purpose

To evaluate changes in inner retinal layer (IRL) thicknesses in patients with type 1 diabetes mellitus (DM1) with no diabetic retinopathy (DR) using two different optical coherence tomography (OCT) devices.

Setting/Venue

IRL and outer retinal layer (ORL) could be affected in neurodegeneration process in DM1 patients before the appearance of DR. OCT is a non-invasive method to check retinal thickness before the appearance of vascular changes.

Methods

90 DM1 and 60 healthy eyes were evaluated using spectral domain (SD)-OCT and swept source (SS)-OCT to measure changes in the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL) and inner nuclear layer (INL) thicknesses in all Early Treatment Diabetic Retinopathy Study (ETDRS) macular areas. Functional tests were performed in both groups including ETDRS 100, 2.5 and 1.25%, and colour vision.

Results

Mean ages were 42.93±13.62 and 41.52±13.05 years in the diabetic and control groups, respectively. Best corrected visual acuity (BCVA) with ETDRS 1.25% was lower in the DM1 patients. Both ETDRS 2.5% and colour vision were lower in the DM1 without reaching statistically differences. Retinal thicknesses in the central area, and in the vertical outer areas were higher in the DM1 group. Differences were found in the IRL with no changes in the outer ones.

Conlusions

Long-term DM1 patients with no DR signs have a maintained visual function, with a decrease in visual acuity (VA) with 1.25% ETDRS contrast. Macular thickness measurements are higher by Spectralis SD-OCT than by DRI Triton SS-OCT. DM1 patients have a decrease in IRL thickness, especially in the GCL at the parafoveal level, generating thinning of the RNFL in the peripheral areas. There are no differences in ORL suggesting a greater photoreceptor resistance to vascular alterations prior DR.

Financial Disclosure

None