Outer Retinal Tubulation A Novel Optical Coherence Tomography Finding

Objective: To describe tubular structures found in the outer retina seen in a variety of retinal disorders. Methods: Sixty-nine eyes of 63 patients were examined with spectral-domain optical coherence tomography. Optical coherence tomography C-scans were correlated with their corresponding B-scans. The prevalence, number, size, and shape of the tubular structures were determined. Results: Branching tubules were identified in the outer retina of 54 patients with age-related macular degeneration and in 9 patients with other diagnoses. The tubules appeared as round or ovoid hyporeflective spaces with hyperreflective borders on the B-scans, measuring 40 to 140 mu m high and 40 to 2260 mu m wide. Morphologic features ranged from single straight or branching tubules to complex cavitary networks, usually overlying areas of pigment epithelial alteration or subretinal fibrosis. The tubules generally remained stable over time. In a retinal practice specializing in advanced age-related macular degeneration, these structures were identified in 60 of 248 patients (24.2%) seen during a 3-month period. Conclusions: Degenerating photoreceptors may become arranged in a circular or ovoid fashion during a process we propose to term outer retinal tubulation. These changes are apparently common in advanced diseases affecting the outer retina and retinal pigment epithelium. This observation has practical implications because these findings can be misinterpreted as intraretinal or subretinal fluid, possibly prompting unnecessary interventions.