Date Published:
2021 Mar 15
Abstract:
PURPOSE: To describe the detailed retinal phenotype of KCNV2-associated retinopathy. STUDY DESIGN: Multicenter international retrospective case series. METHODS: Review of retinal imaging including fundus autofluorescence (FAF) and optical coherence tomography (OCT), including qualitative and quantitative analyses. RESULTS: Three distinct macular FAF features were identified: i) centrally increased signal (n=35, 41.7%), ii) DAF (n=27, 31.1%), and iii) ring of increased signal (n=37, 44.0%). Five distinct FAF groups were identified based on combinations of those characteristics, with 23.5% of patients changing FAF group over a mean (range) follow-up of 5.9 years (1.9-13.1 years). Qualitative assessment was performed by grading OCT into five grades: (i) continuous EZ (20.5%), (ii) EZ disruption (26.1%), (iii) EZ absence, without optical gap and with preserved retinal pigment epithelium (RPE) complex (21.6%); iv) loss of EZ and an hyporeflective zone at the foveola (6.8%); and (v) outer retina and RPE complex loss (25.0%). Eighty-six patients had scans available from both eyes, with 83 (96.5%) having the same grade in both eyes, and 36.1% changed OCT grade over a mean follow-up of 5.5 years. The annual rate of ONL thickness change was similar for right and left eyes. CONCLUSION: KCNV2-associated retinopathy is a slowly progressive disease with early retinal changes, which are predominantly symmetric between eyes. The identification of a single OCT or FAF measurement as an endpoint to determine progression that applies to all patients may be challenging; although ONL thickness is a potential biomarker. Findings suggest a potential window for intervention until 40 years of age.
