Antiviral Treatment Thwarts Recurring Eye Problems From Herpes Simplex

Fran Lowry

September 16, 2010

September 16, 2010 — Oral antiviral prophylaxis after infection with herpes simplex virus (HSV) is associated with a reduced risk for recurring eye problems associated with the disease, according to a new study published in the September issue of the Archives of Ophthalmology.

"...HSV is a common cause of corneal disease and is the leading infectious cause of corneal blindness among developed nations," write Ryan C. Young, BA, from Mayo Clinic, Rochester, Minnesota, and colleagues. "Recurrence rates of ocular HSV after an initial episode have been estimated at 10% at 1 year, 23% at 2 years, 36% at 5 years, and over 60% at 20 years."

Young and colleagues add that periodic reactivations of HSV in the cornea are particularly important, because repeated infection may lead to stromal inflammation or neurotrophic keratitis, resulting in scar or perforation.

In this study, the researchers estimated the incidence of HSV eye disease in a community-based cohort in Olmstead County, Minnesota, from 1976 through 2007. They also investigated the effect of prophylactic oral antiviral therapy on HSV recurrence and outcomes.

During this period, 394 patients with ocular HSV were identified, for an annual incidence of 11.8 per 100,000 people (95% confidence interval [CI], 10.6 - 13.0).

Of this number, 175 patients (44%) had been treated with oral antiviral medication for a mean of 2.8 years.

The study found that patients who were not receiving antiviral therapy at the time of recurrence were 9.4 times more likely (95% CI, 5.0 - 17.9) to have a recurrence of epithelial keratitis; 8.4 times more likely (95% CI, 5.2 - 13.7) to have a recurrence of subepithelial, deep, or necrotizing stromal keratitis; and 34.5 times more likely (95% CI, 10.8 - 111.1) to have a recurrence of blepharitis or conjunctivitis.

A total of 20 patients experienced adverse outcomes, including visual loss and perforation of the cornea. Of these, 17 (85%) were not taking oral antiviral prophylaxis.

The strengths of this study include the large sample size and long-term follow-up, with a mean of 7.7 years, the study authors point out. As well, the community-based cohort study design eliminated referral bias and may be a more accurate reflection of "real-world" ocular HSV.

Limitations were that the study was retrospective and relied on the accuracy and completeness of clinicians' records. Also, laboratory confirmation of HSV was unavailable in most cases, and it is also likely that the study failed to capture all incident cases and episodes of the disease.

The incidence of HSV ocular disease was stable throughout the 32-year period of the study.

"We found a more dramatic protective effect of oral antiviral prophylaxis on recurrences of ocular HSV than had been described previously," the study authors conclude. "The results of this study suggest that oral antiviral prophylaxis should be considered for patients with frequent recurrences of corneal disease. Additionally, we recommend an evaluation of the possible barriers preventing compliance with antiviral prophylaxis and a reassessment of the cost-effectiveness of long-term oral antiviral therapy."

The study was supported by an unrestricted grant from Research to Prevent Blindness Inc and the Mayo Foundation. The study authors have disclosed no relevant financial relationships.

Arch Ophthalmol. 2010;128:1178-1183. Abstract