Application of multicolour reflectance imaging for the characterisation of inherited retinal disorders

Aim To describe the role of multicolour reflectance images (MCI) in the phenotypic diagnosis of inherited retinal disorders (IRDs). Methods A retrospective review of consecutive patients affected by IRDs examined with MCI techniques from January to December 2019 at a tertiary care referral centre. All patients had MCI, fundus autofluorescence and optical coherence tomography taken at the same time point. The ability of each modality to highlight clinical features was assessed. Lesions' size was also measured and compared among imaging modalities. Results Thirty eyes of 15 patients were included in the study, 6 males and 9 females, with a mean age of 44 years (range: 19-57.5). The most frequent clinical diagnosis were: pattern dystrophies, and late-onset retinal degeneration. Next-generation or Sanger sequencing analysis was carried out in all patients. Blue and green reflectance were relevant in highlighting peripheral mottling in fundus albipunctatus, pseudoreticular drusen in late-onset retinal degeneration, parafoveal hyperreflective area in bull's eye maculopathy and crystals in Bietti's crystalline dystrophy. Likewise, it is to mention the ability of infrared reflectance to detect hyperreflective patches in posterior pole in neurofibromatosis type 1 and retinal changes in pattern dystrophies and cone dystrophies. Conclusion Multicolour imaging technique enables the detection of clinical features that could be overlooked by other imaging modalities, allowing accurate phenotypic characterisation of IRDs and guiding genetic diagnose, and may become a meaningful monitoring tool for future treatments.