Novel optical coherence tomography classification of torpedo maculopathy

Abstract

Background: Torpedo maculopathy is a rare condition with a twofold clinical significance. Firstly, it is a differential of atypical congenital hypertrophy of the retinal pigment epithelium. Secondly, visual field loss has been reported. We demonstrate the spectrum of structural abnormality of torpedo maculopathy as seen on optical coherence tomography, and correlate this with age of presentation, fundus autofluorescence, retinal sensitivity loss and visual field abnormality.

Design: A retrospective, observational case series.

Participants: Five Australian patients seen between 2008 and 2013.

Methods: Fundus photography, optical coherence tomography, fundus autofluorescence and visual field analysis. One patient underwent fluorescein angiography.

Main outcome measures: Lesion appearance on each imaging modality, and visual field analysis.

Results: We consistently observed a flat, hypopigmented lesion located in the temporal macula, with a distinctive tip pointing toward the fovea. Optical coherence tomography demonstrated variable retinochoroidal features ranging from mild outer retinal disturbance (type 1) to outer retinal cavitation (type 2). Lesion appearance on short-wave autofluorescence showed varying degrees of hypo-autofluorescence. Near-infrared autofluorescence was performed in two patients and showed a well-defined region of hypo-autofluorescence. Microperimetry showed normal sensitivity over the lesion in one patient and a dense paracentral scotoma over the temporal portion of the lesion in another. On Humphrey field analysis, only one of two patients tested had a paracentral scotoma.

Conclusion: Two types of torpedo maculopathy lesions are described here with unique optical coherence tomography, demographic, fundus autofluorescence and retinal sensitivity features. These may represent different stages of the same disease that evolve over several decades.

Keywords: fundus autofluorescence; microperimetry; optical coherence tomography; torpedo maculopathy.