Multimodal Imaging and Spatial Analysis of Ebola Virus Retinal Lesions and associated Dark Without Pressure in a Cohort of Fourteen Ebola Survivors
IMPORTANCE: Differentiation between Ebola retinal lesions and other retinal pathologies in West Africa is important and the pathogenesis of Ebola retinal disease remains poorly understood. OBJECTIVE: To describe the appearance of Ebola virus disease (EVD) retinal lesions using multimodal imaging to enable inferences regarding potential pathogenesis. DESIGN: Consecutive, prospectively identified, cohort study SETTING: 34 Military Hospital, Freetown, Sierra Leone PARTICIPANTS: Fourteen EVD survivors of Sierra Leonean origin with identified Ebola virus retinal lesions. Mean age 37years (SD 8.8years) 43% Female. EXPOSURES: Ebola virus disease. MAIN OUTCOMES AND MEASURES: Multimodal imaging findings including ultra-widefield (UWF) scanning laser ophthalmoscopy, fundus autofluorescence, swept source optical coherence tomography (OCT), Humphrey visual field analysis, and spatial analysis. RESULTS: 141 Ebola virus retinal lesions were observed in 22 of 27 eyes of fourteen survivors on UWF imaging. 41 lesions were accessible to OCT imaging. Retinal lesions are predominantly non-pigmented with a pale grey appearance. Peripapillary lesions exhibit variable curvatures in keeping with the retinal nerve fiber layer projections. All lesions respect the horizontal raphe and spare the fovea. OCT demonstrates a 'V' shaped hyperreflectivity of the outer nuclear layer overlying discontinuities of the ellipsoid zone and interdigitation zone in the smaller lesions. Larger lesions cause a collapse of the retinal layers and loss of retinal thickness. Lesion shapes are variable but sharp angulations are characteristic. Perilesional areas of dark-without-pressure (thinned ellipsoid zone hyporeflectivity) of variable extent, accompany 89% of lesions. CONCLUSIONS AND RELEVANCE: We demonstrate OCT evidence of localized pathological changes seen at the level of the photoreceptors in small lesions. The relevance of associated areas of dark-without-pressure remains undetermined.