Abstract
Purpose :
A common finding associated with disease progression in macular telangiectasia type 2 (MacTel) is the presence of hyper-reflective changes on optical coherence tomography (OCT). However, an association between hyper-reflectivity and any functional impairment has not yet been evaluated. In a retrospective, cross-sectional cohort study, we quantify hyper-reflectivity on en face-OCT and study its functional relevance to MacTel.
Methods :
Baseline image and functional data from participants of a phase 2 clinical trial (NCT01949324) that studied the effect of Ciliary Neurotrophic Factor in patients with MacTel were analyzed. The projection of hyper-reflectivity within different layers on OCT was used to generate an en face view and measure the en face size of hyper-reflectivity. Ellipsoid zone (EZ)-loss was additionally evaluated, and en face images were superimposed onto microperimetry sensitivity maps permitting an estimate of mean retinal sensitivity within areas displaying hyper-reflectivity and EZ-loss, respectively. Best-corrected visual acuity (BCVA) and reading speed were also analyzed.
Results :
52 eyes from 52 patients were analyzed. Hyper-reflectivity was present in 32 (62%), and EZ-loss in 50 (96%) eyes. Mean lesion size was 0.11mm2 (range 0.01-0.26) for hyper-reflectivity and 0.51mm2 (range 0.02-1.34) for EZ-loss, and lesion sizes correlated strongly (Spearman r=0.79, p<0.001). While both lesions were associated with a significant decrease in retinal sensitivity, comparison of mean sensitivity thresholds in hyper-reflective and EZ-loss lesions differed significantly (0.9 ± 2.6 dB vs 16.3 ± 5.8 dB [mean ± SD]; p<0.001), demonstrating an almost complete loss of sensitivity in hyper-reflective areas.
No correlations were found between the size of hyper-reflectivity and BCVA (r=0.09) or reading speed (r=-0.17).
Conclusions :
We present a method to quantify hyper-reflectivity on en face OCT in MacTel. The en face projection of hyper-reflectivity enables a direct correlation with retinal function as evaluated by microperimetry. We demonstrate that hyper-reflectivity in MacTel is associated with severe functional impairment, resulting in an almost complete loss of retinal sensitivity within those lesions.
This is a 2021 ARVO Annual Meeting abstract.