A Case Series of Occult Macular Dystrophy

Abstract

Purpose. This case series showcases three patients with mild variation in phenotypic presentations of Occult Macular Dystrophy (OCMD), an autosomal-dominant inherited retinal dystrophy (IRD) associated with a retinitis pigmentosa-1-like-1 (RP1L1 ) gene mutation. All cases have confirmed RP1L1 gene mutations and display a range of phenotypic expressions on various imaging modalities and visual acuities. Material and Methods. Three patients of the University Eye Center (UEC) with confirmed RP1L1 gene mutations presented for follow-up or baseline imaging to rule out inherited retinal disease. All patients underwent fundus photography with and without fundus autofluorescence (FAF), optical coherence tomography (OCT), genetic testing, visual fields, and electrodiagnostic testing such as multifocal electroretinogram (mfERG) and/or full-field electroretinogram (ffERG). Results. In two of the three cases, minimal to no funduscopic changes are appreciated on ophthalmoscopy or fundus photography with and without FAF. Effects of OCMD can only be appreciated on OCT imaging, including attenuation or disruption of the photoreceptor integrity line (PIL), and cen- tral depression on visual field testing. One of the three cases displays an unusual presentation with asymmetric central outer retinal atrophy that can be appreciated on fundoscopy as well as other imaging modalities. Conclusion. Although individuals with this IRD typically funduscopically appear normal, there may be a phenotypic spectrum impacting visual potential. Diagnosis of this con- dition is heavily dependent on macular OCT, electrophysio- logical testing, and genetic testing. Keywords Occult Macular Dystrophy, RP1L1, inherited retinal disease, electroretinogram, OCT