Optical Coherence Tomography Characterization of Torpedo Retinopathy: Diving Deep in Search of a Newer Classification System

Abstract

Purpose: Torpedo maculopathy is a rare congenital anomaly of the retinal pigment epithelium (RPE) involving the temporal edge of the macula, often diagnosed incidentally. There is minimal evidence in the ophthalmic literature regarding the multimodal imaging characteristics of these lesions. Existing classification systems inadequately describe detailed optical coherence tomography (OCT) features of the entity. Methods: This retrospective study included 18 torpedo maculopathy lesions from 16 patients at a tertiary care ophthalmic institution in Southern India over 6 years. Patients underwent detailed sociodemographic analysis and multimodal imaging. Prominent OCT biomarkers were analyzed in detail for each case. Results: The mean lesion size was 4.25 mm² (median, 2.96 mm²). Best-corrected visual acuity (BCVA) was 20/20 in the majority (75.0%) of cases. The fovea was involved in 4 patients. Interdigitate zone (IZ) disorganization was observed in all cases. Outer retinal cavitation was present in 7 lesions, often associated with focal choroidal excavation or inner retinal thinning. The remaining 11 lesions from 9 patients did not show outer retinal cavitation. Based on these findings, we propose a modified OCT-based classification for torpedo maculopathy. In the new system, type 1 describes lesions without outer retinal cavitation, whereas type 2 includes lesions with outer retinal cavitation, further subdivided into 4 groups based on inner retinal changes and focal choroidal excavation. Conclusions: This study provides a detailed description of OCT biomarkers associated with torpedo lesions and proposes a more descriptive OCT-based classification system for torpedo maculopathy.