Abstract
Purpose :
Neuroretinal changes are observed on spectral-domain optical coherence tomography (SDOCT) prior to the onset of clinical diabetic retinopthy (DR) in diabetics. The relationship between SDOCT changes in retina layers and diabetic systemic and metabolic risk factors is poorly documented. We examined this relationship in a diabetic cohort.
Methods :
530 patients (mean age[range] 58.9[24-86], 61.3% Male) were prospectively recruited from a primary DR screening service. Participants had non-stereoscopic macula and disc-centered fundus photos and SDOCT (Cirrus Photo 800, Carl Zeiss Meditec) performed in each eye. Fundus photos were graded at a central reading centre with referrable DR defined as moderate non-proliferative DR or worse. SDOCT images were autosegmented using standard software (Orion, Voxeleron LLC) into 7 layers: retina nerve fibre layer (RNFL), ganglion cell-inner plexiform layer (GCIPL), inner nuclear layer (INL), outer nuclear layer (ONL), outer plexiform layer (OPL), photoreceptor layer (PR) and Bruch’s membrane (BR). SDOCT images were reviewed by an experienced image technician to ensure no segmentation error and by a retinal specialist for diabetic macula oedema. Right eye data was used for analyses. Multivariate linear regression analyses adjusted for age, DR status, glycated haemoglobin (HbA1c), diabetes duration and systolic blood pressure (BP) were performed with p-values ≤0.05 considered significant. Retina thickness values were studied at the fovea (1mm diameter), inner annulus (3mm diameter excluding fovea) and outer annulus (6mm diameter excluding inner annulus).
Results :
The mean[SD] duration of diabetes and HbA1c values were 7.29[7.96]years and 7.72[1.62]%, respectively. Increasing age was significantly associated with a thinner GCIPL in all areas. Within the inner annulus, higher HbA1c (β:-0.198, CI:-0.001,-0.396, p=0.050) and higher systolic BP(β:-0.059, CI:-0.022:-0.095, p=0.019) were associated with a thinner RNFL. Referable DR was associated with thinner GCIPL (β:-4.27, CI:-8.53,-0.02, p=0.050)and INL layers (β:-3.02, CI:-4.79,-1.26, p=0.001). At the fovea, referable DR was associated with a thinner ONL (β:-7.79, CI:-5.30,5.05, p=0.003).
Conclusions :
Metabolic risk factors are associated with inner retina thinning in diabetics; Higher systolic BP and HbA1c are associated with thinner RNFL, while changes in the GCIPL and INL are observed when referable DR develops.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.