Eye infections are common and represent a major healthcare burden. Herpes simplex virus type 1 (HSV-1) and, less commonly, HSV type 2 (HSV-2) have been responsible for ocular infections in approximately 400,000 Americans. Moreover, nearly 50,000 new and recurring cases are diagnosed annually in the US with a quarter of cases being the more serious stromal keratitis.1 HSV is involved in the pathogenesis of several ocular disorders and may lead to numerous diseases including blepharitis, vesicular dermatitis of the eyelids, conjunctivits, keratitis, trabeculitis, anterior uveitis, acute retinal necrosis syndrome, retinitis and optic neuritis.2 Adenovirus, however, is the most likely cause of the majority of eye infections.
Adenoviral conjunctivitis is the most frequent cause of red eye and can lead to significant morbidity in patients. Although very common, it remains a challenge for ophthalmologists to both diagnose and treat, mainly because of its non-specific presentation and the numerous conditions that can cause pink eye. Aside from the difficulties in diagnosis and treatment of patients, contagiousness and easy transmission to family members is part of the challenge. At present, clinicians generally only offer supportive measures to treat these patients.
Ganciclovir is an antiviral agent that is selectively active against viral DNA. This prodrug is a synthetic nucleoside analog of 2’-deoxyguanosine 9-(1,3-dihydroxy-2-propoxymethyl) guanine that is phosphorylated by the virus-encoded thymidine kinase.2 Ganciclovir triphosphate then competitively inhibits incorporation of the endogenous nucleotide by the viral DNA polymerase. This results in replication arrest and damage to infected cells. Ganciclovir is currently approved by the US Food and Drug Administration to be used systemically and intravitreally against cytomegalovirus retinitis and, following positive results from clinical trials, topically (Ganciclovir ophthalmic gel; Zirgan®) against herpes simplex dendritic keratitis.3 Topical application of ganciclovir has been shown to penetrate the corneal stroma and reach the aqueous humor at therapeutic levels.4
In May 2011, Yabiku and colleagues reported results of a double-blind, randomized clinical trial of 33 patients diagnosed with adenoviral conjunctivitis.5 They compared the efficacy of ganciclovir ophthalmic gel against placebo in reducing and improving signs, symptoms and transmissibility. They found a trend to faster improvement and less transmissibility to the other eye and people living with affected patients in the treatment group, however these data were not statistically significant.
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