Topical pharmacologic interventions versus placebo for epidemic keratoconjunctivitis

Background: Viruses cause about 80% of all cases of acute conjunctivitis. Human adenoviruses are believed to account for 65% to 90% of cases of viral conjunctivitis, or 20% to 75% of all causes of infectious keratoconjunctivitis worldwide. Epidemic keratoconjunctivitis (EKC) is a highly contagious subset of adenoviral conjunctivitis that has been associated with large outbreaks at military installations and at medical facilities. It is accompanied by severe conjunctival inflammation, watery discharge, and light sensitivity, and can lead to chronic complications such as corneal and conjunctival scarring with discomfort and poor quality of vision. Due to a lack of consensus on the efficacy of any pharmacotherapy to alter the clinical course of EKC, no standard of care exists, therefore many clinicians offer only supportive care.

Objectives: To assess the efficacy and safety of topical pharmacological therapies versus placebo, an active control, or no treatment for adults with EKC.

Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, which contains the Cochrane Eyes and Vision Trials Register; 2021, Issue 4); Ovid MEDLINE; Ovid Embase; Latin American and Caribbean Health Sciences database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), with no restrictions on language or year of publication. The date of the last search was 27 April 2021.

Selection criteria: We included randomized controlled trials in which antiseptic agents, virustatic agents, or topical immune-modulating therapy was compared with placebo, an active control, or no treatment.

Data collection and analysis: We used standard Cochrane methodology.

Main results: We identified 10 studies conducted in Asia, Europe, the Middle East, and North Africa with a total of 892 participants who were treated for 7 days to 6 months and followed for 7 days up to 1.5 years. Study characteristics and risk of bias In most studies participants were predominantly men (range: 44% to 90%), with an age range from 9 to 82 years. Three studies reported information on trial registration, but we found no published study protocol. The majority of trials had small sample sizes, ranging from 18 to 90 participants enrolled per study; the only exception was a trial that enrolled 350 participants. We judged most studies to be at high or unclear risk of bias across risk of bias domains. Findings We included 10 studies of 892 EKC participants and estimated combined intervention effects in analyses stratified by steroid-containing control treatment or artificial tears. Six trials contributed to the comparisons of topical interventions (povidone-iodine [PVP-I], trifluridine, ganciclovir, dexamethasone plus neomycin) with artificial tears (or saline). Very low certainty evidence from two trials comparing trifluridine or ganciclovir with artificial tears showed inconsistent effects on shortening the mean duration of cardinal symptoms or signs of EKC. Low certainty evidence based on two studies (409 participants) indicated that participants treated with PVP-I alone more often experienced resolution of symptoms (risk ratio (RR) 1.15, 95% confidence interval (CI) 1.07 to 1.24) and signs (RR 3.19, 95% CI 2.29 to 4.45) during the first week of treatment compared with those treated with artificial tears. Very low certainty evidence from two studies (77 participants) suggested that PVP-I or ganciclovir prevented the development of subepithelial infiltrates (SEI) when compared with artificial tears within 30 days of treatment (RR 0.24, 95% CI 0.10 to 0.56). Four studies compared topical interventions (tacrolimus, cyclosporin A [CsA], trifluridine, PVP-I + dexamethasone) with topical steroids, and one trial compared fluorometholone (FML) plus polyvinyl alcohol iodine (PVA-I) with FML plus levofloxacin. Evidence from one trial showed that more eyes receiving PVP-I 1.0% plus dexamethasone 0.1% had symptoms resolved by day seven compared with those receiving dexamethasone alone (RR 9.00, 95% CI 1.23 to 66.05; 52 eyes). In two trials, fewer eyes treated with PVP-I or PVA-I plus steroid developed SEI within 15 days of treatment compared with steroid alone or steroid plus levofloxacin (RR 0.08, 95% CI 0.01 to 0.55; 69 eyes). One study found that CsA was no more effective than steroid for resolving SEI within four weeks of treatment (RR 0.84, 95% CI 0.67 to 1.06; N = 88). The evidence from trials comparing topical interventions with steroids was overall of very low level certainty. Adverse effects Antiviral or antimicrobial agents plus steroid did not differ from artificial tears in terms of ocular discomfort upon instillation (RR 9.23, 95% CI 0.61 to 140.67; N = 19). CsA and tacrolimus eye drops were associated with more cases of severe ocular discomfort, and sometimes intolerance, when compared with steroids (RR 4.64, 95% CI 1.15 to 18.71; 2 studies; N = 141). Compared with steroids, tacrolimus did not increase the risk of elevated intraocular pressure (RR 0.07, 95% CI 0 to 1.13; 1 study; N = 80), while trifluridine conferred no additional risk compared to tear substitute (RR 5.50, 95% CI 0.31 to 96.49; 1 study; N = 97). Overall, bacterial superinfection was rare (one in 23 CsA users) and not associated with use of the intervention steroid (RR 3.63, 95% CI 0.15 to 84.98; N = 51). The evidence for all estimates was of low or very low certainty.

Authors' conclusions: The evidence for the seven specified outcomes was of low or very low certainty due to imprecision and high risk of bias. The evidence that antiviral agents shorten the duration of symptoms or signs when compared with artificial tears was inconclusive. Low certainty evidence suggests that PVP-I alone resolves signs and symptoms by seven days relative to artificial tears. PVP-I or PVA-I, alone or with steroid, is associated with lower risks of SEI development than artificial tears or steroid (very low certainty evidence). The currently available evidence is insufficient to determine whether any of the evaluated interventions confers an advantage over steroids or artificial tears with respect to virus eradication or its spread to initially uninvolved fellow eyes. Future updates of this review should provide evidence of high-level certainty from trials with larger sample sizes, enrollment of participants with similar durations of signs and symptoms, and validated methods to assess short- and long-term outcomes.