A controlled trial of oral acyclovir for the prevention of stromal keratitis or iritis in patients with herpes simplex virus epithelial keratitis. The Epithelial Keratitis Trial. The Herpetic Eye Disease Study Group

Clinical Insights: Antimicrobial Therapy for Infectious Uveitis

Infectious uveitis is a major global cause of vision impairment. Despite the eye's immune privilege, afforded by the blood-ocular barrier that restricts microbial entry, several pathogens such as bacteria, viruses, fungi, and parasites can still infiltrate and cause ocular infections and complications. Clinicians often encounter significant challenges in treating infectious uveitis due to limited or ineffective treatment options. Modern molecular techniques and imaging can aid in diagnosing and assessing intraocular infections. Various antimicrobial therapies exist, spanning topical and systemic treatments, but these are constrained by issues like drug concentration, penetration, effective duration, toxicity, and side effects. Treatment approaches also differ based on the infection's etiology. This review provides recent updates on antimicrobial therapies from a clinical perspective, covering topical, systemic, and regional treatments for infectious uveitis.

Herpetic Keratouveitis: Missed Diagnosis Leading to Corneal Perforation

Herpetic uveitis is an easy diagnosis to miss, which can lead to devastating consequences. The aim of this report is to create awareness of how this disease can present, appropriate clues to the diagnosis, and how it should be managed. We report a case of a 70-year-old female who presented with redness and painless blurry vision in her right eye and was treated with topical corticosteroid drops for presumed idiopathic anterior uveitis. Despite initial symptomatic improvement, she reattended with a significant deterioration in vision and was found to have a large corneal infiltrate and associated perforation. The perforation was sealed with corneal gluing, and she was treated for presumed herpetic anterior uveitis with oral acyclovir. Corneal polymerase chain reaction (PCR) specimen was positive for herpes simplex virus DNA. The perforation started to leak again despite repeat corneal gluing, so an emergency therapeutic penetrating keratoplasty was performed. She has remained on prophylactic oral acyclovir for the last 24 months, with no recurrence and the graft remains clear.

Overweight and Obesity as Risk Factors for Recurrent Herpetic Stromal Keratitis during Long-Term Antiviral Prophylaxis

Although past research has shown an association between obesity and herpes simplex virus infection, the relationship between body mass index (BMI) and herpetic stromal keratitis (HSK) recurrence has never been investigated. In this study, we included HSK patients who received oral valacyclovir as prophylactic treatment between January 2016 and January 2021. Recurrence, possible risk factors, and the time to recurrence were recorded during follow-ups. Among the 56 patients included in this study, recurrence was reported in 21 (37.5%) patients. The age at disease onset and mean follow-up time were not significantly different in the recurrence and non-recurrence groups. However, in the Cox regression analysis, BMI ≥ 24 kg/m2 was noted as the variable having significant correlation with recurrence (p = 0.01 in univariate analysis and p = 0.001 in multivariate analysis). In conclusion, overweight and obesity were revealed as risk factors for HSK recurrence in patients receiving long-term antiviral prophylaxis. Further studies are needed to determine the appropriate acyclovir concentrations in the blood or aqueous humour in order to achieve desirable prophylactic effects, especially in the overweight and obese patients.

Comparative Efficacy of Topical Ophthalmic Ganciclovir and Oral Famciclovir in Cats with Experimental Ocular Feline Herpesvirus-1 Epithelial Infection

Purpose: To determine the comparative efficacy of ganciclovir ophthalmic gel and famciclovir oral tablets in cats with experimentally induced ocular feline herpesvirus-1 (FHV-1) epithelial infection. Methods: A randomized, placebo-controlled trial was performed using 16 nonvaccinated, specific pathogen-free cats with experimental FHV-1 infection induced by topical ocular inoculation. Cats received topical ganciclovir 0.15% ophthalmic gel (1 drop 3 times daily, n = 6 cats), oral famciclovir (90 mg/kg twice daily, n = 6), or topical artificial tear gel (1 drop 3 times daily, n = 4) for 14 days. Cats were monitored after inoculation for 30 days. Ophthalmic examinations were performed every 2 days and ocular disease scores calculated. In vivo confocal microscopy was performed, and corneal leukocyte infiltrates quantified. Ocular samples for FHV-1 quantitative polymerase chain reaction (qPCR) and virus isolation assays were collected every 3 days. Hemograms and serum biochemistry panels were performed at intervals. Results: Clinical ocular disease scores and corneal leukocyte infiltrates were significantly lower in the ganciclovir and famciclovir groups compared with placebo, but no significant differences were detected between the antiviral treatment groups. Ocular viral loads determined by qPCR were significantly lower in the ganciclovir group compared with the placebo group, but there were no significant differences between the other study groups. Hemograms and biochemistry panels were unremarkable. Conclusion: Topical application of ganciclovir gel 3 times daily was well-tolerated and displayed similar efficacy at reducing clinical ocular disease scores and corneal inflammation as twice daily oral famciclovir treatment in cats with experimental ocular FHV-1 infection.

Adoption of Innovation in Herpes Simplex Virus Keratitis

Herpes simplex keratitis, caused primarily by human herpes simplex virus type 1 (HSV-1), remains the most common infectious cause of unilateral blindness and vision impairment in the industrialized world. Major advances in the care of HSV keratitis have been driven in large part by the landmark Herpetic Eye Disease Study randomized clinical trials, which were among the first in ophthalmology to reflect emerging trial conventions, including multicenter subject enrollment, double-masking, placebo controls, and a priori sample size determinations. The results of these trials now form much of the evidence basis for the management of this disease. However, management patterns in clinical practice often deviate from evidence-based care. These perceived quality gaps have given rise to the evolving field of implementation science, which is concerned with the methods of promoting the application of evidence-based medicine within routine care. To overcome variations in the quality and consistency of care for HSV keratitis, a range of clinical- and technology-based innovations are proposed. The most pressing needs include the following: a rational and tractable disease classification scheme that provides an immediate link between the anatomical localization of disease (corneal epithelial, stromal, or endothelial) and the appropriate treatment, and the actualization of an electronic medical record system capable of providing evidence-based treatment algorithms at relevant points of care. The latter would also input data to population-wide disease registries to identify implementation-rich targets for quality improvement, education, and research. These innovations may allow us to reduce the human and economic burdens of this highly morbid, and often blinding, disease.

Clinical outcomes of herpes simplex keratitis: Two-year experience from a quaternary eye care centre in Sydney, Australia

PURPOSE

To report anti-viral therapy and outcomes for patients with herpes simplex keratitis (HSK) in a quaternary centre in Sydney, Australia.

METHODS

A retrospective case review of patients who received anti-viral medications for any form of HSK was conducted. Cases were identified from pathology results, pharmacy records and hospital coding data from 2012 to 2013. Clinical details including initial anti-viral treatment and outcome were collated from the medical records. Outcome was determined from when initial anti-viral treatment was stopped or changed, and classified as either clinically resolved, partially resolved or worsened for therapeutic indication; or as either success or failure for prophylaxis.

RESULTS

Anti-viral therapy was given for therapeutic and prophylactic indications at presentation in 252 (85%) and 44 patients (15%), respectively. Topical aciclovir five times daily and valaciclovir in doses ranging from 500 mg to 1 g, one to three times daily were the preferred anti-viral therapies. One hundred and fourteen patients (n = 114/296, 38.5%) also received topical corticosteroids. An outcome was determined for 210/296 (71%) patients. For therapeutic indication, half of the patients (90/174) partially resolved within 8 days, with best outcomes achieved for endothelial HSK (8/11, 73%) and keratouveitis (21/36, 58%). Adverse events, observed in 20% (35/174) of patients, included corneal perforation (n = 8) and secondary bacterial keratitis (n = 6). Prophylaxis with antiviral therapy was successful in two-thirds of patients after 6 months.

CONCLUSIONS

Clinical and visual outcomes varied with the type of HSK and prescribed therapies. Diverse initial anti-viral therapies were identified; standardising them may improve outcomes.

Blocking HSV-1 glycoprotein K binding to signal peptide peptidase reduces virus infectivity in vitro and in vivo

HSV glycoprotein K (gK) is an essential herpes protein that contributes to enhancement of eye disease. We previously reported that gK binds to signal peptide peptidase (SPP) and that depletion of SPP reduces HSV-1 infectivity in vivo. To determine the therapeutic potential of blocking gK binding to SPP on virus infectivity and pathogenicity, we mapped the gK binding site for SPP to a 15mer peptide within the amino-terminus of gK. This 15mer peptide reduced infectivity of three different virus strains in vitro as determined by plaque assay, FACS, and RT-PCR. Similarly, the 15mer peptide reduced ocular virus replication in both BALB/c and C57BL/6 mice and also reduced levels of latency and exhaustion markers in infected mice when compared with control treated mice. Addition of the gK-15mer peptide also increased the survival of infected mice when compared with control mice. These results suggest that blocking gK binding to SPP using gK peptide may have therapeutic potential in treating HSV-1-associated infection.

Signal peptide peptidase (SPP) and HSV-1 glycoprotein K (gK) are essential genes in the host and virus, respectively. SPP and gK genes are both highly conserved. Previously we reported that gK binding to SPP is important for virus infectivity in vitro and in vivo. In this study we have identified the gK binding site to SPP and have shown that a gK peptide that blocks gK binding to SPP can block HSV-1 infectivity in vitro and in vivo using different strains of virus and mice. Thus, the ability of this peptide to block gK binding to SPP may be a useful tool to control HSV-1-induced eye disease in patients with herpes stromal keratitis (HSK).

Antiviral Therapy for Varicella Zoster Virus (VZV) and Herpes Simplex Virus (HSV)-Induced Anterior Uveitis: A Systematic Review and Meta-Analysis

Topic: Herpes simplex virus (HSV) and varicella zoster virus (VZV) are the most common ocular pathogens associated with infectious anterior uveitis. Currently, there are a number of antiviral agents administered to treat viral anterior uveitis (VAU). However, there is no consensus or guidelines about the most appropriate approach leading for the best treatment outcomes with fewer ocular complications. Clinical Relevance: To perform a systematic review and meta-analysis of the efficacy of different antiviral therapies in the management of anterior uveitis secondary to HSV and VZV. Methods: We searched PubMed, Web of Science, CINAHL, OVID, and Embase up to January 2020. Randomized trials, non-randomized intervention studies, controlled before and after studies and observational studies assessing the effect of oral and or topical treatments for VAU were considered. Data extraction and analysis with evaluation of the risk of bias in the included trials were performed. Results: Oral acyclovir demonstrated a statistically significant good treatment outcome in the management of VZV anterior uveitis (vs. placebo) (OR 0.26, 95% CI 0.11-0.59), but did not have similar effect in HSV anterior uveitis (OR 0.47, 95% CI 0.15-1.50). In the treatment of VZV anterior uveitis, there was significant superiority of oral acyclovir-7 day course-over topical acyclovir (OR 4.17, 95% CI 1.28-13.52). Whereas, there was no significant superiority of one of the following treatment regimens over the others: topical acyclovir over topical corticosteroids (OR 1.86, 95% CI 0.67-5.17), and oral acyclovir-7 day course-over oral acyclovir-14 day course-(OR 0.21, 95% CI 0.01-4.50) or oral valaciclovir (OR 1.40, 95% CI 0.48-4.07). Conclusion: Treatment of HSV and VZV anterior uveitis is currently based on individual experiences and limited literature, largely due to weak clinical trial evidence in this regard. Our results highlight the existence of a substantial gap in our evidence base. This finding might contribute to future research studies to ascertain the role of different antiviral therapies in the treatment of VAU. Systematic Review Registration: PROSPERO registration number: CRD420202 00404.

Development, Implementation, and Evaluation of Treatment Guidelines for Herpes Simplex Keratitis in Sydney, Australia

PURPOSE

To develop and measure the uptake of a local guideline for herpes simplex keratitis (HSK) and to standardize initial antiviral therapy in Australia.

METHODS

The Registered Nurses' Association of Ontario Toolkit: "Implementation of Best Practice Guidelines" was used to develop, implement, and evaluate the guideline at Sydney Eye Hospital. An implementation team was established to reach consensus on antiviral therapy guidelines through review of available evidence, identifying stakeholders, facilitators and barriers, creating strategies for implementation, and developing a sustainability plan. An audit of all adult HSK cases during a 6-month postguideline implementation period was conducted, and the results were compared with a preimplementation audit. A web-based survey was created to assess clinician awareness, usage, and level of knowledge of the guideline.

RESULTS

Clinicians, pharmacists, and administrative staff were identified as stakeholders. Changing clinician's behavior was the major barrier to implementation. Implementation strategies included printed and online materials and lectures to clinicians. A postimplementation audit included 85 patients, and 95 clinicians received a web-based survey. The dose of the prescribed antiviral medication was in alignment with the local guideline in 80% (51/64) of the patients compared with 73% (163/223) before implementation (P = 0.331). Stromal HSK with ulceration and keratouveitis were excluded because there were no recommendations before implementation. Over 70% of clinicians (30/41) were aware of the guideline and accessed them through educational resources.

CONCLUSIONS

Guidelines for the management of HSK may improve standardization of initial antiviral therapy in HSK. In practice, most clinicians were aware of and adhered to the local guideline.

20 years since the Herpetic Eye Disease Study: Lessons, developments and applications to clinical practice

Herpes Simplex Virus (HSV) is the most common virus that causes eye disease. Although around 60% of the world's population are seropositive for HSV antigens, fortunately, it is estimated that only 1% of seropositive individuals develop eye disease. The most common ocular manifestation of HSV is keratitis, while uveitis and retinal necrosis occur in a small number of cases. HSV keratitis is a debilitating disease, for several reasons: pain , photophobia, and vision loss in acute disease, latency of the virus which leads to infection reactivation from various triggers, scarring, and neovascularisation, leading to permanent vision loss with poor visual rehabilitation prospects. The Herpetic Eye Disease Study (HEDS) was a landmark series of randomised controlled trials in the 1990s that set the benchmark for evidence-based treatment guidelines for anterior eye herpetic disease. Since this time, there has been a change in the distribution of seroprevalence of herpes in the community, a simplified diagnostic classification, advances in treatment options, an emergence of new and a better understanding of risk factors, and discoveries in science that show promise for vaccine and novel future treatments. However, many of the principles of the HEDS study remain rightly entrenched in clinical practice. In this article, the HEDS study is revisited 20 years on through the lens of published literature, to determine current best practise and look towards the future.

Clinical Features of Herpes Simplex Keratitis in a Korean Tertiary Referral Center: Efficacy of Oral Antiviral and Ascorbic Acid on Recurrence

PURPOSE

To describe the clinical manifestations of herpes simplex keratitis (HSK) in a tertiary referral center in South Korea and to determine whether ascorbic acid treatment prevents recurrence of herpetic epithelial keratitis.

METHODS

This retrospective cohort study included all consecutive patients with herpetic keratitis referred to our center from January 2010 to January 2015. Clinical features, ocular complications, and recurrences were recorded.

RESULTS

In total, 149 eyes of the 133 patients (72 male and 61 female) were followed for an average of 24.6 ± 13.2 months. Sixteen (12.0%) patients had bilateral HSK. The most frequent HSK subtype was epithelial keratitis (49.7%), which was followed by stromal keratitis (23.5%). Epithelial keratitis was the most likely subtype to recur. Complications occurred in 122 (81.9%) eyes. The most common complication was corneal opacity. Recurrences were observed in 48 (32.2%) eyes. The recurrence rates were lower in the prophylactic oral antiviral agent group (16 / 48 eyes, 33.3% vs. 49 / 101 eyes, 48.5%) and the ascorbic acid treatment group (13 / 48 eyes, 27.1% vs. 81 / 101 eyes, 70.3%) compared with the groups without medications. Univariate logistic regression analysis revealed that both factors significantly reduced the risk of recurrence (acyclovir: odds ratio, 0.25; 95% confidence intervals, 0.12 to 0.51; ascorbic acid: odds ratio, 0.51; 95% confidence intervals, 0.20 to 0.91).

CONCLUSIONS

This retrospective study described the clinical findings of HSK in a tertiary referral center in South Korea. Prophylactic oral antiviral agent treatment and oral ascorbic acid administration may lower the risk of recurrence.

Toxic Keratoconjunctivitis

Toxic keratoconjunctivitis (TK) is an underrecognized complication of ophthalmic drug use and various environmental or occupational exposures. A detailed history and clinical examination are important to identify the offending agent(s). Common drug-related causes of TK include preservatives in ophthalmic medications, topical antimicrobials, and topical anesthetics. Alternatives to benzalkonium chloride as well as preservative-free formulations should be considered in patients requiring long-term topical medication. More advanced cases of TK may require preservative-free topical steroids and/or antibiotics, and occasionally surgical intervention. Early recognition and appropriate management of TK may help prevent permanent ocular and visual damage.

Management of herpes simplex virus epithelial keratitis

PURPOSE OF REVIEW

To review recent advancements in the management of herpes simplex virus (HSV) epithelial keratitis.

RECENT FINDINGS

Trifluridine eye drop, acyclovir (ACV) ointment, ganciclovir gel, and oral ACV are still the main therapeutic agents. Cryopreserved amniotic membrane has been recently used as an adjuvant treatment. Resistance to ACV has become a concerning issue. The animal models of HSV vaccine are able to reduce HSV keratitis. New antivirals are under development.

SUMMARY

Current cases of HSV epithelial keratitis are manageable with available medications, but new advancements are required to decrease disease burden in the future. HSV vaccine can be revolutionary.

Confocal Microscopic Analysis of a Rabbit Eye Model of High-Incidence Recurrent Herpes Stromal Keratitis

PURPOSE

Using CJLAT, a chimeric herpes simplex virus (HSV-1) that produces a high incidence of herpes stromal keratitis (HSK) in latently infected rabbits, and in vivo confocal microscopy (CM), we characterized the cellular events that precede the development of HSK.

METHODS

Thirty days after infection, in vivo CM was performed daily for 10 days and then weekly for up to 80 days after infection.

RESULTS

We detected 3 types of subclinical corneal lesions before HSK was clinically apparent: (1) small epithelial erosions; (2) regenerating epithelium overlying small cell infiltrates within the basal epithelial cell layer; and (3) dendritic-like cells within the basal epithelial layer overlying stromal foci containing infiltrating cells. Sequential in vivo CM observations suggested that subclinical foci resolved over time but were larger and more abundant with CJLAT than with wild-type HSV-1 McKrae. Active HSK was observed only with CJLAT and was initially associated with a large epithelial lesion overlying stromal immune cell infiltrates.

CONCLUSIONS

These results suggest that replication in the cornea of reactivated virus from the trigeminal ganglia produces epithelial lesions, which recruit immune cell infiltrates into the basal epithelial layer and anterior stroma. The virus is usually cleared rapidly eliminating viral antigens before the arrival of the immune cells, which disperse. However, if the virus is not cleared rapidly, or if an additional reactivation results in an additional round of virus at the same site before the immune cells disperse, then the immune cells are stimulated and may induce an immunopathological response leading to the development of HSK.

Clinical efficacy of oral ganciclovir for prophylaxis and treatment of recurrent herpes simplex keratitis

Background:

Herpes simplex keratitis (HSK) caused by herpes simplex virus 1 (HSV-1), which has high recurrent rate and incidence of severe vision loss, is the leading cause of infectious blindness in the world. The aim was to explore the clinical efficacy of oral ganciclovir (GCV) in the prevention of recurrent HSK.

Methods:

A multicenter, prospective, randomized, single-blind, and controlled clinical trial was conducted from April 2010 to June 2013. One hundred seventy-three patients (173 eyes involved) who were diagnosed as recurrent HSK definitely, including stromal keratitis and corneal endotheliitis, were divided into three groups randomly: negative control (placebo) group was topically administered with 0.15% GCV ophthalmic gel, 4 times per day and 0.1% fluorometholone eye drops, 3 times per day until resolution of HSK; positive control acyclovir (ACV) group was topically adopted the same ophthalmic gel and eye drops and additionally received oral ACV 400 mg 5 times a day for 10 weeks and followed by 400 mg 2 times per day for 6 months; test GCV group was topically adopted the same treatment as negative control group and additionally received oral GCV 1000 mg 3 times per day for 8 weeks. The symptoms and signs were evaluated before and after the therapy 1^st week, 2^nd week and then followed up every 2 weeks until recovery. Furthermore, we followed up recurrence of HSK for every 3 months after recovery and then assessed the cure time, recurrent rate and adverse reactions.

Results:

One hundred and seventy-three patients were followed up 7–48 months (mean 32.1 ± 12.3 months), but 34 patients were failed to follow-up. The cure time was 12.1 ± 4.3, 11.9 ± 4.0 weeks in negative control (placebo) group and positive control ACV group respectively (P = 0.991), which was longer than that in test GCV group (8.6 ± 2.8 weeks) and there was a significant difference between test GCV group and negative control (placebo) group or positive control ACV group (P = 0.000). Furthermore, the recurrent rate was higher in negative control (placebo) group (47.3%) than that in positive control group ACV (26.7%) and test GCV group (17.2%), and there was a great significant difference among the three groups (P = 0.007), but there was no significant difference between positive control ACV group and test GCV group (P = 0.358). In addition, there was no obvious adverse reaction expect neutropenia (only one patient in test GCV group).

Conclusion:

Short-term oral GCV could cure recurrent HSK and endotheliitis, shorten the course, reduce recurrent rate of HSK and have confirmed safety.

Current aspects on the management of viral uveitis in immunocompetent individuals

Viruses are a fundamental etiology of ocular inflammation, which may affect all structures of the organ. Advances in molecular diagnostics reveal an increasingly broader spectrum of virus-associated intraocular inflammation, including all members of the herpes family, rubella virus, and other more rare causes such as Epstein–Barr and chikungunya virus. In particular, viruses of the herpes family are important causes of anterior and posterior uveitis. Owing to their often fulminant clinical course and persistence in ocular tissues, a clear differential diagnosis between alpha- and beta-type herpes viruses is essential to guide acute and long-term treatment. Here, we review the epidemiology, clinical, and laboratory findings of virus-associated uveitis with emphasis on their therapy and management and include our own experience.

Antiviral treatment and other therapeutic interventions for herpes simplex virus epithelial keratitis

BACKGROUND

Eye disease due to herpes simplex virus (HSV) commonly presents as epithelial keratitis which, though usually self-limiting, may persist or progress without treatment.

OBJECTIVES

To compare the relative effectiveness of antiviral agents, interferon, and corneal debridement in the treatment of HSV epithelial keratitis.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 12), PubMed (January 1946 to 31 December 2014), EMBASE (January 1980 to 31 December 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to 31 December 2014), System for Information on Grey Literature in Europe (OpenGrey) (January 1995 to 31 December 2014), BIOSIS (January 1926 to 5 May 2014), Scopus (January 1966 to 31 December 2014), Japan Science and Technology Institute (J-Global) (January 1975 to 31 December 2014), China National Knowledge Infrastructure (CNKI) (January 1979 to 31 December 2014), British Library's Electronic Table of Contents (Zetoc) (January 1993 to 7 May 2014). We looked for trials listed on the the metaRegister of Controlled Trials (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en), Chinese Clinical Trial Registry, the U.S. Food and Drug Administration (FDA) (www.fda.gov/), National Institute for Health and Clinical Excellence (NICE) (www.

EVIDENCE

nhs.uk) and the European Medicines Agency (EMA) (www.ema.europa.eu/ema/) as of 31 December 2014. There were no language or date restrictions in the search for trials. We also culled literature digests and conference proceedings as of 15 April 2014. There were no language or date restrictions in the search for trials.

SELECTION CRITERIA

Randomised and quasi-randomised trials of HSV dendritic or geographic epithelial keratitis were included that reported the proportion of eyes healed at one week, two weeks, or both after enrolment.

DATA COLLECTION AND ANALYSIS

We tabulated data on study characteristics, risk of bias, and outcomes and used direct comparisons to estimate a risk ratio (RR) and, when feasible, a hazard ratio (HR) with a 95% confidence interval (CI). Heterogeneity was assessed by an inconsistency index. A multiple treatment comparison meta-analysis consolidated direct and indirect comparisons of relative healing at 14 days.

MAIN RESULTS

One hundred thirty-seven studies involving 8333 eyes met the inclusion criteria. Placebo-controlled studies were heterogeneous in comparison with idoxuridine (RR 1.74; 95% CI 1.03 to 2.91) and few in number for vidarabine (RR 1.81; 95% CI 1.09 to 3.01), interferon (RR 1.32; 95% CI 1.06 to 1.64), and debridement. Vidarabine (RR 1.13; 95% CI 1.02 to 1.25), trifluridine (RR 1.30; 95% CI 1.18 to 1.43), acyclovir (RR 1.23; 95% CI 1.14 to 1.34), and brivudine (RR 1.34; 95% CI 1.18 to 1.51) were more effective than idoxuridine. Trifluridine (RR 1.17; 95% CI 1.03 to 1.32) and acyclovir (RR 1.11; 95% CI 1.03 to 1.19) were more effective than vidarabine. No significant differences in healing emerged among trifluridine, acyclovir, brivudine, and foscarnet although few studies compared brivudine or foscarnet with other antivirals. Any potential advantage of ganciclovir compared to acyclovir was mitigated by study heterogeneity and possible publication bias. Only one study evaluated the joint use of two topical antivirals. In a limited number of studies, oral acyclovir (RR 0.92; 95% CI 0.79 to 1.07) or the combination of oral acyclovir with a topical antiviral (RR 1.36; 95% CI 0.68 to 2.74) appeared as effective as a single topical antiviral agent. Compared to topical antiviral monotherapy, the combination of an antiviral with either interferon or debridement had inconsistent effects on expediting healing and improving outcome.

AUTHORS' CONCLUSIONS

Placebo-controlled studies of HSV epithelial keratitis are limited to superseded interventions. Trifluridine and acyclovir are more effective than idoxuridine or vidarabine and similar in therapeutic effectiveness. Brivudine and foscarnet do not substantially differ in effectiveness from trifluridine or acyclovir. Ganciclovir is at least as effective as acyclovir. The addition of interferon to a nucleoside antiviral agent and the combination of debridement with antiviral treatment need to be further assessed to substantiate any possible advantage in healing.

Herpes zoster ophthalmicus: comparison of disease in patients 60 years and older versus younger than 60 years

OBJECTIVE

To study the clinical course of herpes zoster ophthalmicus (HZO) and to compare the demographics, treatments, and outcomes in patients aged <60 years versus patients aged ≥60 years at the time of diagnosis.

DESIGN

Retrospective chart review of all 112 patients presenting for management of HZO from January 1, 2008 to December 31, 2008.

PARTICIPANTS

A total of 112 patients (58 aged <60 years and 54 aged >60 years) at the time of HZO onset.

INTERVENTIONS

Anterior segment complications, treatments, and surgical procedures were documented at 3 months, 6 months, and 1 year, and then annually for the remainder of the follow-up period.

MAIN OUTCOME MEASURES

Intraocular pressure, inflammation, steroid use, surgical procedures, anterior segment complications, post-herpetic neuralgia, and delayed herpes zoster pseudodendrites.

RESULTS

Equal numbers of patients were affected with HZO in the younger and older age groups (51.8%, n = 58 vs. 48.2%, n = 54, respectively, P = 0.69). The most common decade of HZO onset was between 50 and 59 years. Younger patients were more likely to be healthy compared with older patients (P = 0.05). Delayed herpes zoster pseudodendrites were more common in the younger patients (36.7% vs. 16.7%, P = 0.03). The mean number of flares per patient-years was significantly higher in the younger patients (z test, P = 0.024). Post-herpetic neuralgia, neurotrophic keratopathy, and secondary infectious keratitis were more frequent in the older patients (P = 0.05). Prevalence of corneal perforation, corneal thinning, cataract formation, and glaucoma was similar between the 2 groups. Most patients in both groups (84.2% of younger patients and 89.5% of older patients) were taking topical steroids 3 years after referral for HZO.

CONCLUSIONS

Herpes zoster ophthalmicus affects individuals aged younger than and older than 60 years in similar numbers, with the most common decade of onset between age 50 and 59 years. Younger patients had more episodes of delayed pseudodendritiform keratitis and flares of inflammation compared with older patients, who had more problems related to neurotrophic keratopathy.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Antiviral treatment and other therapeutic interventions for herpes simplex virus epithelial keratitis

BACKGROUND

Eye disease due to herpes simplex virus (HSV) commonly presents as epithelial keratitis.

OBJECTIVES

To compare the relative effectiveness of antiviral agents, interferon, and corneal débridement in the treatment of acute HSV epithelial keratitis.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2010, Issue 4), MEDLINE (January 1950 to October 2010), EMBASE (January 1980 to October 2010), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2010), Zetoc (British Library's Electronic Table of Contents), System for Information on Grey Literature in Europe (openSIGLE), Biosciences Information Service (BIOSIS), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), Japan Information Center of Science and Technology (JICST-EPlus), and China Academic Journals database (CAJ) via China National Knowledge Infrastructure (CNKI) with citations confirmed using China/Asia On Demand (COAD). There were no language or date restrictions in the search for trials. All databases except CNKI and COAD were last searched on 27 October 2010, CNKI and COAD were searched on 1 April 2010. We also searched literature digests, conference proceedings and reference lists.

SELECTION CRITERIA

Of 152 eligible studies,106 comparative treatment trials involving 5872 eyes with dendritic or geographic epithelial keratitis were analysed for corneal healing over two weeks.

DATA COLLECTION AND ANALYSIS

Interventions were compared at 14 days after trial enrolment by calculating a risk ratio (RR) that was adjusted with indirect RR, assessed by an inconsistency index (I(2) ) and supplemented by a seven-day RR and a hazard ratio (HR).

MAIN RESULTS

Idoxuridine, though uncertainly better in healing outcome than control because of few trials with 14-day follow up, allowed earlier corneal re-epithelialisation. Vidarabine resulted in a significantly better outcome than placebo in one trial (RR 1.96; 95% CI 1.10 to 3.49). Compared to idoxuridine, in combined direct and indirect analyses, vidarabine (RR 1.11; 95% CI 1.03 to 1.19), trifluridine (RR 1.31; 95% CI 1.20 to 1.42), acyclovir (RR 1.23; 95% CI 1.16 to 1.31), brivudine (RR 1.38; 95% CI 1.18 to 1.61), and ganciclovir (RR 1.40; 95% CI 1.25 to 1.57) were significantly more effective. Trifluridine (RR 1.12; 95% CI 1.04 to 1.21) and acyclovir (RR 1.11; 95% CI 1.05 to 1.19) appeared more effective than vidarabine. No significant differences were found in comparisons between acyclovir, trifluridine and brivudine. The comparison of ganciclovir to acyclovir was limited by heterogeneity and possible publication bias. The joint use of two topical antivirals (RR 1.00; 95% CI 0.89 to 1.12) and the use of oral acyclovir alone (RR 0.92; 95% CI 0.79 to 1.07) or combined with a topical antiviral (RR 1.08; 95% CI 0.99 to 1.17) appeared as effective as topical antiviral therapy. Compared to antiviral monotherapy, the combination of an antiviral with interferon (RR 1.03; 95% CI 0.99 to 1.07) or with débridement (RR 1.04; 95% CI 0.95 to 1.14) did not yield significantly better outcomes but may have accelerated healing. The corneal epithelial healing outcome was improved when antiviral therapy was added to débridement (RR 1.21; 95% CI 1.04 to 1.42).

AUTHORS' CONCLUSIONS

Trifluridine and acyclovir are more effective than idoxuridine or vidarabine, and similar in therapeutic effectiveness. Brivudine and ganciclovir are at least as effective as acyclovir. While not improving outcome, the combination of interferon and an antiviral agent may speed healing. The effectiveness of corneal epithelial débridement is improved by an antiviral agent.

Prospects for Developing an Effective Vaccine Against Ocular Herpes Simplex Virus Infection

One of the hallmarks of herpes simplex virus (HSV) infection is the establishment of a lifelong latent infection accompanied by periods of recurrent disease. Primary HSV infections or repeated clinical recurrences do not elicit immune responses capable of completely preventing recurrences of endogenous virus. It is therefore questionable if vaccination approaches that seek to mimic the immune response to natural infection will reduce infection or disease due to an exogenous viral challenge. Approaches to the induction of protective responses by altering or enhancing both innate and adaptive immunity, using novel vaccines specifically tested in models of HSV infections of the eye, such as recombinant viral vaccine vectors and DNA vaccines, are detailed in this review.

Therapeutic interventions for herpes simplex virus epithelial keratitis

BACKGROUND

Many clinical trials have been performed on the acute treatment of dendritic epithelial keratitis. Surveys of ocular antiviral pharmacology and of herpes simplex virus (HSV) eye disease have evaluated different interventions, but a systematic review of all comparative clinical studies has not previously been undertaken.

OBJECTIVES

The objective of this review was to compare the effects of various therapeutic interventions for dendritic or geographic HSV epithelial keratitis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) in The Cochrane Library (Issue 3, 2007), MEDLINE (1966 to September 2007), EMBASE (1980 to September 2007), LILACS (up to September 2007), SIGLE (1980 to September 2007), ZETOC (21 September 2007), BIOSIS (up to 2005), JICT-EPlus (up to 2005), Index Medicus (1960 to 1965), Excerpta Medica Ophthalmology (1960 to 1973), reference lists of primary reports and review articles, and conference proceedings pertaining to ocular virology.

SELECTION CRITERIA

This review included comparative clinical trials that assessed one-week or two-week healing rates of topical ophthalmic or oral antiviral agents and or physical or chemical debridement in people with active epithelial keratitis.

DATA COLLECTION AND ANALYSIS

The review author extracted data and assessed trial quality. Interventions were compared by the proportions of participants healed at seven days and at fourteen days after trial enrolment.

MAIN RESULTS

This review included data from 99 trials that randomised a total of 5363 participants. The topical application of vidarabine, trifluridine, acyclovir or ganciclovir resulted in a high proportion of participants healing within one week of treatment. Among these antiviral agents, no treatment emerged as significantly better for the therapy of dendritic epithelial keratitis. Insufficient placebo-controlled studies were available to assess debridement and other physical or physicochemical methods of treatment. Interferon monotherapy had a slight beneficial effect on dendritic epithelial keratitis but was not better than other antiviral agents. Interferon was very effective when combined with another antiviral agent such as trifluridine.

AUTHORS' CONCLUSIONS

Currently available antiviral agents are effective and nearly equivalent. The combination of a nucleoside antiviral with either debridement or with interferon seems to speed healing. Future trials of the acute treatment of HSV epithelial keratitis must aim to achieve adequate statistical power for assessing the primary outcome of epithelial healing and should consider the effect of lesion size and other characteristics on treatment response.

Evidence-based treatment of herpes simplex virus keratitis: a systematic review

Herpes simplex virus (HSV) keratitis is a common cause of ocular and visual morbidity. In this article, we systematically review published randomized clinical trials (RCTs) for HSV epithelial and stromal keratitis in order to establish a rational evidence-based foundation for treatment of these disorders. Articles for review were identified in the MEDLINE database from January 1, 1966, to May 30, 2006. Our review criteria stipulated that each study be performed in prospective, randomized, and double-blinded fashion, that it be controlled, and that it rely on specific clinical criteria for diagnosis and outcome. Of articles thus identified in the English language press, 38 articles met our review criteria, 30 for HSV epithelial keratitis and 8 (comprising 7 RCTs) for HSV stromal keratitis. From these studies, we concluded that the best evidence from treatment trials on HSV epithelial keratitis supports the use of topical trifluridine and topical or oral acyclovir, and suggests a possible additional benefit for topical interferon. The best evidence from RCTs for HSV stromal keratitis supports the use of topical corticosteroids given together with a prophylactic antiviral to shorten the duration of active HSV stromal keratitis, and the use of long-term suppressive oral acyclovir therapy to reduce the incidence of recurrent HSV keratitis.

Therapeutic interventions for herpes simplex virus epithelial keratitis

BACKGROUND

Many clinical trials have been performed on the acute treatment of dendritic epithelial keratitis. Surveys of ocular antiviral pharmacology and of herpes simplex virus (HSV) eye disease have evaluated different interventions, but a systematic review of all comparative clinical studies has not previously been undertaken.

OBJECTIVES

The objective of this review was to compare the effects of various therapeutic interventions for dendritic or geographic HSV epithelial keratitis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) in The Cochrane Library (Issue 3, 2006), MEDLINE (1966 to July 2006, week 3), EMBASE (1980 to 2006, week 30), LILACS (up to August 2006), SIGLE (1980 to March 2005), ZETOC (1 August 2006), BIOSIS (up to 2005), JICT-EPlus (up to 2005), Index Medicus (1960 to 1965), Excerpta Medica Ophthalmology (1960 to 1973), reference lists of primary reports and review articles, and conference proceedings pertaining to ocular virology.

SELECTION CRITERIA

This review included comparative clinical trials that assessed one-week or two-week healing rates of topical ophthalmic or oral antiviral agents and or physical or chemical debridement in people with active epithelial keratitis.

DATA COLLECTION AND ANALYSIS

The review author extracted data and assessed trial quality. Interventions were compared by the proportions of participants healed at seven days and at fourteen days after trial enrolment.

MAIN RESULTS

This review included data from 98 trials that randomised a total of 5211 participants. Compared to idoxuridine, the topical application of vidarabine, trifluridine, or acyclovir resulted in a significantly greater proportion of participants healing within one week of treatment. Among these latter three antiviral agents, no treatment emerged as significantly better for the therapy of dendritic epithelial keratitis. Insufficient placebo-controlled studies were available to assess debridement and other physical or physicochemical methods of treatment. Interferon monotherapy had a slight beneficial effect on dendritic epithelial keratitis but was not better than other antiviral agents. Interferon was very effective when combined with another antiviral agent such as trifluridine.

AUTHORS' CONCLUSIONS

Currently available antiviral agents are effective and nearly equivalent. The combination of a nucleoside antiviral with either debridement or with interferon seems to speed healing. Future trials of the acute treatment of HSV epithelial keratitis must aim to achieve adequate statistical power for assessing the primary outcome of epithelial healing and should consider the effect of lesion size and other characteristics on treatment response.

Herpetic eye disease in diabetic patients

PURPOSE

To study the incidence of herpetic eye disease (HED) of the ocular surface in diabetics.

DESIGN

Observational historical cohort study.

SETTING

A district of the largest health maintenance organization in Israel (the Central District of Clalit Health Services).

PARTICIPANTS

We reviewed the electronic medical records of all patients older than 50 years (159634 patients) in the district, and of these, 22382 (14.0%) patients had diabetes mellitus.

METHODS

All filled prescriptions for acyclovir eye ointment between January 1, 2001 and December 31, 2003 (1483 tubes) and all hemoglobin A1c laboratory tests during 2003 (41910 tests) were documented. An ocular surface HED event was defined when a patient consumed at least 1 tube of topical acyclovir per month, whereas no acyclovir use was documented 3 months before and 3 months after that event.

MAIN OUTCOME MEASURES

Incidence of ocular surface HED events in diabetics compared with nondiabetics adjusted for age and gender.

RESULTS

After age and gender adjustment, significantly more diabetics had ocular surface HED (5.21 per thousand) compared with nondiabetics (4.27 per thousand; P<0.0001). Stratification by age revealed a significantly higher prevalence of HED in diabetics, aged 60 to 79 years. Recurrent herpetic events occurred during the study period in 25.2% of HED-affected diabetics, and in 16.6% of HED-affected nondiabetics (P = 0.05). Diabetics with poor glycemic control (mean annual hemoglobin A1c > 9%) consumed significantly more ocular acyclovir (P = 0.01). Multivariate analysis revealed this effect to be independent of age, gender, place of birth, or place of residency.

CONCLUSIONS

Ocular surface HED is significantly more common among patients with diabetes mellitus. Poor glycemic control correlates with increased consumption of ocular acyclovir in diabetic patients.

[The latest in herpes simplex keratitis therapy]

Herpetic keratitis is characterized by spontaneous recurrences and a risk of vision loss, the latter being more serious when relapses are frequent and severe. Two clinical forms are commonly distinguished: epithelial keratitis, usually quickly resolved with topical antivirals, and stromal keratitis, which has a slower progression, even when both steroids and antivirals are used. Great strides have been made during the last 20 Years in the therapy of herpes keratitis, which is now considered and treated as a chronic disease. Randomized controlled studies definitively showed the decrease in spontaneous herpetic ocular events in patients treated with long-term oral acyclovir. The effectiveness of preventive treatment has also been shown during high-risk periods, especially ocular surgery, in patients with a history of herpes keratitis. However, the optimal duration and dosage of antiviral prevention have yet to be defined. We can also hope that in the future novel antiviral strategies such as vaccination will reduce the place of herpes keratitis as an indication for corneal graft.

Prescribing trends in infectious keratitis: a survey of New Zealand ophthalmologists

PURPOSE

To obtain an overview of the treatment of infectious diseases of the cornea by New Zealand ophthalmologists and to analyse the data in the context of evidence-based treatment recommendations.

METHODS

A questionnaire was sent to all New Zealand ophthalmologists. It comprised 23 multiple-choice questions pertaining to the characteristics of the respondents, the nature of their practice and their prescribing preferences in infectious conjunctivitis and keratitis.

RESULTS

Of the 93 ophthalmologists surveyed, 80.6% returned the questionnaire. Of those in clinical practice, 91.4% regularly treated patients with corneal disease. A subspecialty interest in cornea was stated by 12.5% of these. This paper reports observations for adenoviral conjunctivitis and adenoviral, Herpes simplex, varicella zoster, bacterial, acanthamoebal and fungal keratitis. In some conditions prescribing practice varied dramatically, such as in adenoviral conjunctivitis where 50% of respondents prescribed a corticosteroid and 51.6% an antibiotic, whereas 37.5% prescribed only lubrication or no topical treatment. In other conditions there was a high degree of agreement between ophthalmologists; indeed, all ophthalmologists treated Herpes simplex dendritic keratitis with topical acyclovir. No statistically significant differences in prescribing habits were identified between subspecialist and non-subspecialist groups, although some important clinical differences emerged. There were occasional marked differences in response when the age group of respondents was considered, particularly in relation to the management of adenoviral infections and bacterial keratitis.

CONCLUSIONS

The findings of this survey suggest that the majority of New Zealand ophthalmologists generally follow international guidelines for the management of infectious keratitis. The identified variations in management provide a foundation for informed clinical debate and the development of treatment guidelines, in line with evidence-based recommendations.

Bilateral herpetic keratoconjunctivitis

PURPOSE

To review the clinical characteristics and visual outcomes of patients with bilateral herpetic keratitis.

DESIGN

Retrospective, noncomparative, observational case series.

PATIENTS AND METHODS

A retrospective review of medical records of 544 patients with herpes simplex virus (HSV) eye disease treated between January 1996 and September 2001 was performed at the Department of Ophthalmology, University of Minnesota. Seven patients (1.3%) with bilateral herpetic keratoconjunctivitis were identified.

RESULTS

In these seven patients, the age at the initial onset of corneal disease ranged from 7 weeks to 46 years, with a median of 18 years and a mean of 19.3 years. Five patients had systemic atopy, and two patients had severe ocular rosacea. Systemic immune disorders were noted in two patients. Recurrent blepharoconjunctivitis was noted in 8 eyes (57%), epithelial keratitis in 12 eyes (85.7%), stromal keratitis in 9 eyes (64.3%), necrotizing stromal keratitis in 5 eyes (35.7%), and progressive endotheliitis in 2 eyes (14.2%). Corneal complications included opacification, neovascularization, and corneal thinning or perforation. Penetrating keratoplasty was performed in 1 eye, in which endophthalmitis subsequently developed and which required enucleation. Four patients with continued use of oral antiviral prophylaxis (acyclovir 400 mg twice daily) since September 1999 showed significant decreases in recurrence. The average remission in these four patients was 1.7 years. The visual acuity at the last follow-up was 20/40 or worse in 6 eyes (42.8%).

CONCLUSIONS

In contrast to unilateral HSV keratitis, our patients with bilateral herpetic corneal infections had underlying atopy or immune deviations and evinced more protracted clinical courses. Long-term prophylactic antiviral treatment has reduced the incidence of recurrence in this group of patients.

[Corneal herpes: what's new?]

The prognosis of herpetic keratitis has been dramatically improved during the past years because of a better understanding of their physio-pathologic phenomenons, and mostly because of the use of very efficient antiviral drugs. Superficial keratitis are easily cured in most cases; deep stromal keratitis, that often require corticosteroid treatment, are more difficult to heal. Prophylactic treatment of the recurrences by oral antiviral drugs represents a promising new concept for herpetic keratitis.

The outcome of corneal grafting in patients with stromal keratitis of herpetic and non-herpetic origin

AIM

To evaluate the outcome of corneal grafting in patients with stromal keratitis of herpetic (HSK) and non-herpetic origin, using predefined diagnostic criteria and standardised postoperative therapeutic strategies.

METHODS

384 adult immunocompetent recipients of a corneal graft for herpetic (n = 186) or non-herpetic (n = 198) keratitis were followed up prospectively for up to 5 years.

RESULTS

The herpetic group displayed significantly more corneal vascularisation (p = 0.013), more epithelial defects (p = 0.049), lower corneal sensitivity (p <0.001), more graft rejection episodes (p = 0.002), and required larger grafts (p<0.001). However, the postoperative course of visual acuity, endothelial cell numerical density, and rate of graft failures were similar in both groups. After 5 years, cumulative probability of graft survival in HSK patients (40.85%) was similar to that observed in individuals with non-herpetic keratitis (50.15%; log rank = 0.874; relative risk: 1.04).

CONCLUSION

Despite a markedly higher preoperative risk profile in herpetic eyes, the functional outcomes of grafts in individuals with keratitis of herpetic or non-herpetic origin were similar. Probably the most important contribution is a consequent close follow up and a therapeutic strategy including systemic prophylaxis of viral recurrence and of graft rejection by well adopted local steroid therapy.

Tegument-specific, virus-reactive CD4 T cells localize to the cornea in herpes simplex virus interstitial keratitis in humans

Herpes stromal keratitis (HSK) is a prevalent and frequently vision-threatening disease associated with herpes simplex virus type 1 (HSV-1) infection. In mice, HSK progression occurs after viral clearance and requires T cells and neutrophils. One model implicates Th1-like CD4 T cells with cross-reactivity between the HSV-1 protein UL6 and a corneal autoantigen. HSK can be prevented by establishing specific immunological tolerance. However, HSK can also occur in T-cell receptor-transgenic X SCID mice lacking HSV-specific T cells. To study the pathogenesis of HSK in the natural host species, we measured local HSV-specific T-cell responses in HSK corneas removed at transplant surgery (n = 5) or control corneas (n = 2). HSV-1 DNA was detected by PCR in two specimens. HSV-specific CD4 T cells were enriched in three of the five HSK specimens and were not detectable in the control specimens. Reactivity with peptide epitopes within the tegument proteins UL21 and UL49 was documented. Responses to HSV-1 UL6 were not detected. Diverse HLA DR and DP alleles restricted these local responses. Most clones secreted gamma interferon, but not interleukin-5, in response to antigen. HSV-specific CD8 cells were also recovered. Some clones had cytotoxic-T-lymphocyte activity. The diverse specificities and HLA-restricting alleles of local virus-specific T cells in HSK are consistent with their contribution to HSK by a proinflammatory effect.

Oral acyclovir for the management of herpes simplex virus keratitis in children

PURPOSE

To evaluate the use of oral acyclovir in pediatric patients with herpes simplex virus (HSV) keratitis.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

Seven pediatric patients seen at the University of Minnesota Hospitals and Clinics with herpes simplex virus (HSV) infectious epithelial keratitis between January 1992 and October 1998. Patient ages ranged from 6 weeks to 5 years at time of presentation with a median of 1.7 and mean of 1.9 years.

INTERVENTION

All patients received oral acyclovir; six of seven patients also received topical antiviral medications. Three of seven patients had topical antiviral therapy fail before being placed on oral acyclovir, and the remaining four patients were placed on oral acyclovir primarily.

RESULTS

All patients showed resolution of HSV infectious epithelial keratitis. Three patients have been maintained on prophylactic dosage of oral acyclovir because of recurrent disease or because they have been chronically treated with topical corticosteroids for immune stromal keratitis. All patients tolerated acyclovir well, and there were no adverse reactions.

CONCLUSIONS

Oral acyclovir is useful in treating HSV infectious epithelial keratitis in pediatric patients. It is beneficial in treating infectious epithelial keratitis and prophylactically either while treating with topical corticosteroids for immune stromal keratitis or for preventing recurrent infectious epithelial keratitis.

Treatment of viral diseases of the cornea and external eye

Ocular virus infections remain an important cause of corneal and external disease. Herpes simplex, the most important, is easily treated when it is confined to the epithelium. New studies indicate that herpetic stromal disease and iritis are effectively treated with a combination of corticosteroid and antiviral without additional risk. Recurrences of ocular herpetic disease can be reduced with acyclovir given orally; the benefit seems to be greatest in patients who have had at least one episode of stromal keratitis. Herpes zoster can be treated with either acyclovir or famciclovir, but to be effective, treatment must be initiated within 72 hours of onset. Early treatment reduces the risk of post-herpetic neuralgia and may reduce the risk of ocular complications. Adenovirus infection (epidemic keratoconjunctivitis) is often spread by the ophthalmologist. New medications such as cidofovir appear to be effective against the adenoviruses in non-human systems and may have some effect in man, although previously, drugs that appeared to have an effect in vitro have proven to be ineffective in the clinical setting.

The impact of the herpetic eye disease studies on the management of herpes simplex virus ocular infections

Herpes simplex virus (HSV) is a leading cause of chronic infectious ocular disease in the United States. The morbidity from recurrent herpetic episodes is high, and the resultant corneal scarring may require penetrating keratoplasty for visual rehabilitation. Effective treatments for acute episodes of HSV have been verified by early Herpetic Eye Disease Study (HEDS) trials. The recent HEDS trial on the efficacy of oral acyclovir as prophylaxis against recurrent stromal keratitis represents the first report of a treatment likely to reduce long-term scarring from herpetic disease. This article reviews all the HEDS trials and the implications of their findings for the management of patients with ocular HSV.

The placebo effect

Placebos have been traditionally regarded as deceptive therapies and have not been understood in the broader context of social symbols and of interpersonal factors that surround the healing process itself. Although the power of inert substances to heal is well recognized, the placebo effect also influences the outcome of conventional therapies. The role of the placebo in modern medicine is poorly defined because of a lack of a common understanding of what the placebo effect is and because of the negative connotions associated with its use. The response rate to placebo varies by illness. The natural course of disease and patient or physician bias can be misinterpreted as a placebo response. In research, the placebo effect is therapeutic noise to be removed by placebo-controlled trials. Few studies are designed to measure the placebo response rate directly. Placebos are a reminder of how little is known about mind-body interaction. The placebo effect may be one of the most versatile and underused therapeutic tools at the disposal of physicians.

Acyclovir for the prevention of recurrent herpes simplex virus eye disease. Herpetic Eye Disease Study Group

BACKGROUND

Long-term treatment with antiviral agents has been shown to prevent recurrences of genital and orofacial herpes simplex virus (HSV) disease, but it is uncertain whether prophylactic treatment can prevent recurrences of ocular HSV disease.

METHODS

We randomly assigned 703 immunocompetent patients who had had ocular HSV disease within the preceding year to receive 400 mg of acyclovir or placebo orally twice daily. The study outcomes were the rates of development of ocular or nonocular HSV disease during a 12-month treatment period and a 6-month observation period.

RESULTS

The cumulative probability of a recurrence of any type of ocular HSV disease during the 12-month treatment period was 19 percent in the acyclovir group and 32 percent in the placebo group (P<0.001). Among the 337 patients with a history of stromal keratitis, the most common serious form of ocular HSV disease, the cumulative probability of recurrent stromal keratitis was 14 percent in the acyclovir group and 28 percent in the placebo group (P=0.005). The cumulative probability of a recurrence of nonocular (primarily orofacial) HSV disease was also lower in the acyclovir group than in the placebo group (19 percent vs. 36 percent, P<0.001). There was no rebound in the rate of HSV disease in the six months after treatment with acyclovir was stopped.

CONCLUSIONS

After the resolution of ocular HSV disease, 12 months of treatment with acyclovir reduces the rate of recurrent ocular HSV disease and orofacial HSV disease. Long-term antiviral prophylaxis is most important for patients with a history of HSV stromal keratitis, since it can prevent additional episodes and potential loss of vision.