Discrepancies in central foveal intensity with different autofluorescence modalities in CNGB3‐associated achromatopsia and correlation with integrity of ellipsoid zone on optical coherence tomography

Abstract

Aims/Purpose: Autofluorescence (AF) imaging and optical coherence tomography (OCT) aid assessment of retinal disease. We compared relative central foveal signal intensity obtained with two AF platforms in patients with CNGB3‐associated achromatopsia, identifying cases with apparent discrepancy between the two modalities. We then explored whether such discrepancies associated with ellipsoid zone (EZ) features on OCT.Methods: Patients with CNGB3‐associated disease were identified from the genetic database of a large referral centre. Those who had undergone blue (488 nm) AF (Heidelberg Spectralis) and green (532 nm) AF (Optos plc) imaging during the same visit were included. The central foveal signal was graded qualitatively in as brighter or darker compared to the wider macular region. OCT images from the same visit were also graded as to whether there the EZ line was continuous centrally. This grading was performed blinded to the AF grading.Results: Forty‐four patients (24 females) were included. Mean (SD) age was 32 (18) years. Each patient had the same AF grading for both eyes with each modality. For blue AF images, the central foveal signal was darker in all cases; for green AF images, the central fovea was darker in most, but brighter in 12 patients (4 females). Mean (SD) age of this group was 23 (13) years, whilst mean (SD) age of the other patients was 36 (19) years. Patients showing discrepancy were significantly younger (p = 0.028). The central EZ line was gradable in 43 patients: it was interrupted in 33% (n = 14) of right and 33% (n = 14) of left eyes. All patients in whom AF discrepancy was seen had a continuous EZ line centrally.Conclusions: Discrepancy was observed between the two AF modalities in 27% of patients, where the central fovea appeared hyperfluorescent in green, but not in blue, AF images. These patients were significantly younger, and all had a continuous EZ line centrally. The findings further define structural alterations in achromatopsia.