Abstract
Purpose :
To examine (1) the retinal structure by optical coherence tomography angiography (OCTA) and function by means of multifocal electroretinography (mfERG) in eyes with and without diabetic retinopathy (DR), (2) if the local retinal function assessed by mfERG latencies and amplitudes have any correspondence with the retinal lesions.
Methods :
This was a prospective study that examined consecutive patients with type 2 diabetes at a tertiary eye care centre; 145 eligible participants with or without DR underwent comprehensive ophthalmic examination, OCT for retinal thickness measures, OCTA for angiometric measures, mfERG and ultra-wide field view fundus photography. Right eyes of all participants were analyzed. 43 (30%) participants had DR graded by an experienced observer. 12/43 (27%) had diabetic macular edema (DME).
Results :
Zone-wise analysis per Early Treatment Diabetic Retinopathy Study (ETDRS) showed significantly thicker full retinal measures in nine zones in eyes with DR compared to those with no DR. Inner retinal thickness measures did not differ between the two groups. mfERG latencies of P1 in rings 1-6, N1 in rings 2-6 were significantly delayed; P1 amplitudes in rings 5-6 were reduced in DR group with or without DME. In the absence of DME, the amplitudes were spared, with only the latencies being delayed. The OCT ETDRS grid was overlayed onto mfERG hexagons to obtain averaged amplitude and latency measures in eyes with DR per ETDRS zones. OCT thickness and mfERG amplitude were negatively and significantly correlated in inner superior, inner temporal and outer superior zones, while the OCT thickness and mfERG latencies were positively and significantly correlated. Zones with features such as cystic spaces (p<0.001), sub-retinal fluid (p<0.001), pigment epithelial detachment (p<0.001) showed significantly higher mfERG amplitudes; presence of epiretinal membrane, abnormalities of the retinal pigment epithelium, and ellipsoid layer defects were associated with significantly lower mfERG amplitudes in eyes with DR.
Conclusions :
Both structural and functional compromise is evident in individuals with type 2 diabetes with DR. OCTA and mfERG are helpful in assessing this selective compromise in individuals with diabetic retinopathy.
This is a 2020 ARVO Annual Meeting abstract.