Selective rod outer segment disruption in commotio retinae - a finding identified on Multicolour® Imaging.

Purpose: To report Multicolour® imaging (MCI) findings in commotio retinae (CR) involving macula and correlate topographically with outer retinal layers on optical coherence tomography (OCT).

Methods: This retrospective study included participants with CR involving macula without any other type of traumatic maculopathy and imaged with OCT and MCI.

Results: The study included 16 eyes of 16 patients (14 males). Age of presentation ranged from 7 to 56 years and presenting vision ranged from 6/6 to 6/24. On OCT, increased reflectivity and obliteration of hyporeflective ellipsoid zone (EZ) and interdigitation zone (IZ) at CR region were seen. Fovea and other retinal layers were spared. On MCI, white areas due to hyperreflectance corresponding to CR were noted on individual colour reflectance channels and on composite multicolour image. In all cases, foveal reflectance pattern was unaffected. The affection of the EZ and IZ at the CR on OCT was associated with increased reflectance on individual wavelength colour channels on MCI. Foveal sparing on MCI correlated with photoreceptor layer sparing at the fovea on OCT. In 6 (38%) cases with follow-up details, normal reflectivity of EZ and IZ was noted in the region of previous CR as early as 1-week post-presentation. White coloration on multicolour image showed resolution.

Conclusion: Foveal sparing was common and rod-dominated areas were affected in CR. Corresponding changes on MCI showed hyperreflectance areas on individual wavelength colour channels. Studies combined with photoreceptor-specific electrophysiological tests, adaptive optics imaging and histological evidences would be required in future.