This cross-sectional study assessed ophthalmic features specific to Ebola virus disease.
Researchers evaluated 564 Ebola virus antibody-positive survivors and 635 antibody-negative contacts of those survivors from the 5-year PREVAIL III study. Seropositivity for Ebola was defined as an Ebola virus glycoprotein IgG antibody titer of 548 U/ml or higher; a lower titer was considered negative. Investigators took ocular history and performed ophthalmic exam and testing, slit-lamp exam and dilated fundus exam. Examination included vision, color vision, autorefraction, best-corrected visual acuity, confrontational visual fields, ocular alignment and motility, pupillary exam and IOP measurement. The optic nerve and macula were imaged by OCT. The presence or absence of uveitis was noted.
Compared with antibody-negative close contacts, survivors of Ebola described more trouble seeing (49% vs. 36%), sensitivity to light (49% vs. 40%) and ocular redness (26% vs. 18%). Both groups had a median BCVA of 20/20. Regarding color vision testing, 29% of survivors and 19% of close contacts had color vision deficit. Mean IOP was significantly lower in survivors (12 mm Hg vs. 14 mm Hg).
Survivors were more likely to have inflammatory changes, including posterior synechiae (4.3% vs. 0.5%), vitreous cells (7.8% vs. 0.5%) and retinal scars (4.6% vs. 1.6%). Approximately 26% of survivors and 12% of close contacts had uveitis. Among these patients, survivors often had intermediate uveitis (34% vs. 6.5%) and had thicker central subfield thickness on OCT (mean difference=14.4 μm). Imaging by OCT also revealed retinal scars, epiretinal membranes, vitreomacular traction and intraretinal fluid in survivors.
Survivors with uveitis tended to stay 2.7 days longer in the Ebola treatment unit than those without uveitis, and were more likely to complain of eye pain (46% vs. 31%) and have a lower IOP (12 mm Hg vs. 13 mm Hg).
Since this is a cross-sectional study, there are significant limitations. The follow-up window of Ebola survivors was short. If the study followed patients for a longer period of time, the researchers could have collected more information on the incidence of new ocular findings associated with surviving Ebola virus infection. In addition, examining patients right after acute infection could provide more information about the timeline of findings associated with onset of symptoms. Since eye care specialists are not widely available in the region of Africa where the study took place, ocular symptoms may have motivated close contacts of survivors to volunteer for the study, potentially leading to an overall enrichment of ocular pathology. Because an emerging infectious disease was being studied, the examiners were not masked.
Ebola virus disease is associated with ocular disease. Patients can develop uveitis, posterior synechiae, pupillary membranes, cataracts, retinal scars, macular edema, epiretinal membranes and vitreomacular traction. Although there was an increased risk of retinal scars with Ebola, the lesions appeared to largely spare the fovea since visual acuity remained normal. Color vision loss was twice as common in survivors of Ebola than in close contacts. Survivors also had a reduction of approximately 1 D in accommodation. The findings suggest there may be multifaceted visual defects that involve changes in the central nervous system, in addition to changes in the eye. Ophthalmic care after Ebola virus infection may require both medical and surgical interventions; it is important to treat the ocular sequelae in these patients.