Clinical and imaging characteristics of outer retinal folds in eyes with retinitis

Abstract

Purpose: To describe clinical and imaging characteristics of the outer retinal folds (ORF) in cases of retinitis, retinochoroiditis, and chorioretinitis.

Methods: Retrospective review of retinitis cases with presence of ORFs either at presentation or during follow up.

Results: ORFs were seen adjacent to retinitis lesions in 16 eyes of 14 cases (retinitis post-febrile illness n = 10, toxoplasma retinochoroiditis n = 2, fungal chorioretinitis n = 2) either at presentation (n = 2) or during follow up (n = 14). Optical coherence tomography (OCT) appearance was outer retinal vertical stout lesions involving ellipsoid, external limiting membrane, and outer nuclear layer. All the cases had a presence of past or concurrent subretinal fluid and/or subretinal hyperreflective material when ORF was seen. ORF resolved with variable outer retinal atrophy over a mean period of 2.86 months.

Conclusion: ORF is observed in cases of retinitis with subretinal fluid either at presentation or during resolution. It is not specific to any etiological disease. Differentiation of this sign from vertical outer retinal stripes in viral retinitis on OCT is important to avoid misinterpretation.

Keywords: Chorioretinitis; optical coherence tomography; outer retinal folds; retinitis; retinochoroiditis.

Figure 1

Case of fungal chorioretinitis post SARS-CoV-2 infection; (a) left eye fundus photo showing whitish chorioretinitis lesions at presentation with SRF and subretinal hyperreflective material; (b) follow up at 3 days showing appearance of ORF (arrowhead); (c) appearance of multiple ORFs around the retinitis at 1 month; (d) well-delineated ORFs at 6 weeks; (e and f) gradual resolution of ORFs at 4 and 7 months, respectively. Complete resolution was seen at 9 months

Figure 2

OCT montage scans corresponding to case in Figure 1; (a) Dome-shaped hyperreflective central chorioretinitis lesion with subretinal hyperreflective material (arrow); (b) Appearance of ORF at day 3 follow up; (c-f) show gradual resolution of ORF height, thickness along with focal ellipsoid distortion at months 1, 1.5, 4, and 7, respectively

Figure 3

Case of retinitis post-febrile illness (a) at presentation. Vertical OCT scan marked on (a) at presentation (b) shows inverted V appearance (c) of incomplete ORF with SRF. At 6 weeks follow up, resolution of retinitis is seen along with formation of mutliple ORFs (arrow) on red reflectance imaging as white lines (d) and hyperautofluorescent on autofluorescene imaging (e). OCT showed conversion of incomplete to complete ORF (f)

Figure 4

Various morphological patterns of ORF on OCT; (a-c) demonstrate incomplete ORFs with variable dome-shaped elevation of overlying OPL and presence of SRF; (d-f) demonstrate ORF at edge of retinitis with variable OPL curvatures raging from semicircular (d), dome-shaped elevation (e) to shallow elevation (f); (g) shows presence of two ORFs resolving with focal ellipsoid loss in (h)