Abstract
Purpose :
The impact of peripheral retinal lesions (PL) captured in ultrawide-field (UWF) imaging on diabetic retinopathy (DR) remains undefined. This study's purpose was to assess the presence of PL and their correlation to early signs of macular microvasculopathy, metabolic dysfunction and neurodegeneration in patients with type II diabetes and early stages of retinal disease.
Methods :
We included type II diabetic patients with early DR in this cross-sectional study. 45° color fundus photographs (Topcon) and 200° UWF images (Optos) were graded for the presence of retinal lesions to determine DR severity. Lesions were considered peripheral if located anterior to 45°. RTVue Optical Coherence Tomography Angiography (OCT-A) algorithms were used to evaluate foveal avascular zone (FAZ) -area, -perimeter, and -acircularity index and full-retina vessel density (VD) in a 300μm-ring adjacent to the fovea. The superficial/deep capillary plexus VD was evaluated in a parafoveal ring corresponding to the inner ETDRS fields. Peripapillary vessel oxygen saturation (SO2) was assessed with dual-wavelength oximetry. Spectralis OCT was used for thickness measurements of the peripapillary retinal nerve fiber- and each of the 9 retinal layers at the macula.
Results :
For the 161 eyes (80 left eyes) of 81 patients (34 female) included, DR grading differed significantly comparing fundus photographs and UWF images, resulting in a higher DR level in 64 eyes (39.8%) on UWF images (p<0.0001). Topcon images showed a higher DR grade in 6 eyes only. We categorized 115, 41 and 5 (Topcon) versus 67, 77 and 17 (Optos) eyes as having no, mild and moderate non-proliferative DR, respectively. PL were identified in 97 eyes (60.3%) on UWF images. Among the 115 eyes without signs of DR in the central 45°, 59 had PL. We found no significant correlation between the presence of PL with FAZ area, -perimeter, and -acircularity index, superficial/deep parafoveal VD, foveal full-retina VD, arterial/venous SO2, or thickness of (neuro-)retinal layers in the macular/peripapillary region.
Conclusions :
DR affects the periphery first and independently of early signs of macular microvascular impairment, metabolic dysfunction, and retinal sensory neuropathy. These results suggest that evaluation of the retinal periphery becomes crucial in DR screening if PL are shown to predict DR progression and outcome.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.