Comparison of white light and scanning laser ophthalmoscopy ultra-widefield pseudocolor reflectance images in foveal hypoplasia

Abstract

Purpose : To explore the presence of concentric macular rings on ultra-widefield scanning laser ophthalmoscopy (SLO) pseudocolor images and white light reflectance in patients with foveal hypoplasia.

Methods : Patients with diagnoses of ocular or oculocutaneous albinism, or foveal hypoplasia, were identified. Patients were included if they had fundus images available performed both with ultra-widefield (SLO) pseudocolor imaging (Optos California, Optos plc, Dunfermline, UK) and a white light reflectance camera (devices included Topcon fundus cameras, Topcon Corporation, and VK-2 camera, Kowa Company Limited). Presence or absence of the concentric macular rings sign was noted.

Results : Ten patients met the inclusion criteria. Mean (SD) age was 37.8 (15.6) years (median 38.5; range, 12-61 years); 7 were female. Clinical diagnoses were oculocutaneous albinism (8 patients), ocular albinism (1 patient) and congenital nystagmus with foveal hypoplasia (1 patient). Molecular diagnoses were obtained in 5 patients: these included variants in TYR (1 patient), OCA2 (3 patients) and GPR143 (1 patient). Ultra-widefield pseudocolor imaging showed concentric macular rings in 8 patients; the 2 patients in whom this sign was absent had abnormal scleral structure (staphylomatous or dome-shaped) on optical coherence tomography imaging. White light reflectance images did not show concentric macular rings in any patient.

Conclusions : Concentric macular rings were noted in all SLO ultra-widefield pseudocolor images (except those with irregular scleral curvature), but not in white light images. In the presence of nystagmus, optical coherence tomography can be challenging, whilst a single SLO image is often obtainable. The macular rings sign can thus be clinically useful in identifying foveal hypoplasia in these patients. We hypothesise that the phenomenon is likely a manifestation of Newton’s rings, which arise from interference between light reflected from adjacent flat and curved surfaces.

This is a 2020 ARVO Annual Meeting abstract.