OUTER RETINAL COLUMNAR ABNORMALITIES: A Novel Optical Coherence Tomography Sign of CRB1 Maculopathy?

Purpose: To report a novel optical coherence tomography sign in the context of CRB1 -related maculopathy termed outer retinal columnar abnormalities (ORCA).

Methods: Retrospective, multicenter, observational case series of 14 eyes of eight patients with molecularly confirmed CRB1 -related maculopathy and ORCA. Multimodal imaging scans and medical records of patients with CRB1 -related maculopathy were reviewed. Outcome measures included best-corrected visual acuity, central subfield thickness on spectral-domain optical coherence tomography, presence of ORCAs, and analysis of their change in appearance over time.

Results: At baseline, mean age was 18±10 years (range 9-36 years). All patients had an isolated macular dystrophy except for 1 case harboring a triallelic pathogenic variant. Variant c.498_506del was found in 9 cases (88%). At presentation, ORCA were visible on macular spectral-domain optical coherence tomography in all cases as multiform, vertical, hyperreflective, columnar alterations extending from the ellipsoid to the outer plexiform layer, with a variable degree of hyporeflective cystic spaces in the outer and inner nuclear layers. Over 6±4.7 follow-up years, the presence of ORCA varied greatly with a decrease in ORCA associated with sequential development of retinal atrophy.

Conclusion: A high suspicion for CRB1 -associated retinal dystrophy should arise in the presence of ORCA on spectral-domain optical coherence tomography, prompting genetic testing.