By Dr. Hemali Kanabar | Evidence-Based Ophthalmology
When it comes to herpes simplex virus (HSV) affecting the eye, management can be as complex as the virus itself. To bring clarity and standardization to treatment, a series of pivotal multicenter randomized controlled trials—the Herpetic Eye Disease Study (HEDS)—were conducted across the 1990s and early 2000s.
The HEDS trials addressed six critical clinical questions regarding HSV keratitis, and their findings still guide our evidence-based treatment today.
Let’s break them down one by one.
🧪 1. Should You Add Topical Steroids to Antivirals for HSV Stromal Keratitis?
📚 Study: Wilhelmus et al., 1994
🎯 Question: Do topical steroids help in stromal keratitis when the patient is already on topical antivirals?
✅ Key Finding: YES.
Patients receiving topical corticosteroids in addition to topical antivirals had:
- Reduced treatment failures
- Faster resolution of inflammation
- Improved visual outcomes
📌 Clinical Tip: Don’t hesitate to use topical steroids (e.g., prednisolone acetate) in immune-mediated stromal keratitis—but always co-administer with antivirals to prevent viral reactivation.
💊 2. Does Oral Aciclovir Help in Stromal Keratitis Already on Topical Therapy?
📚 Study: Barron et al., 1994
🎯 Question: Is there added benefit of oral aciclovir when a patient is already on topical steroids and topical antivirals?
🚫 Key Finding: NO significant benefit.
- Oral aciclovir (400 mg five times/day) did not improve outcomes or delay treatment failure at 16 weeks.
📌 Clinical Tip: Don’t routinely add oral aciclovir in stromal keratitis if the patient is already on effective topical steroid and antiviral therapy.
👁️ 3. Should Oral Aciclovir Be Used in HSV Iridocyclitis?
📚 Study: HEDS Group, 1996
🎯 Question: Does oral aciclovir help in HSV iridocyclitis when the patient is already on topical steroids?
📊 Key Finding: The protective effect of oral aciclovir bordered on statistical significance.
- Some benefit was noted in reducing treatment failure, but not conclusively.
📌 Clinical Tip: Oral aciclovir may be considered in HSV iridocyclitis, especially in patients at risk of recurrence.
🔁 4. Can Oral Aciclovir Prevent Recurrence of HSV Keratitis?
📚 Study: HEDS Group, 1998
🎯 Question: Is prophylactic oral aciclovir effective in reducing recurrence of HSV keratitis?
✅✅ Key Finding: YES.
- 12-month prophylaxis with oral aciclovir (400 mg BID) reduced recurrence rates:
- From 32% → 19% overall
- Epithelial keratitis: 14% → 9%
- Stromal keratitis: 28% → 14%
📌 Clinical Tip: Long-term oral aciclovir is especially beneficial in patients with recurrent stromal keratitis or frequent relapses.
🧬 5. What Predicts Recurrent HSV Keratitis?
📚 Study: HEDS Group, 2001
🎯 Question: What demographic or disease factors influence recurrence risk?
🔍 Key Findings:
- History of epithelial keratitis did not increase risk of epithelial recurrence.
- Number of prior stromal episodes = higher likelihood of stromal recurrence.
📌 Clinical Tip: Use recurrence pattern—not just past infection type—to guide prophylaxis decisions.
⚠️ 6. Are There Lifestyle Triggers for HSV Recurrence?
📚 Study: HEDS Group, 2000
🎯 Question: Do common factors like stress, infection, sunlight, menstruation, or contact lens wear increase HSV recurrence risk?
🚫 Key Finding: No significant association found.
📌 Clinical Tip: Despite popular belief, these triggers weren’t proven to significantly affect recurrence. Focus more on clinical history and ocular findings.
📍 Bonus Insight: Does Delaying Steroid Use Worsen Vision?
Observation: Delaying the start of topical steroids in stromal keratitis did not affect visual outcomes at 6 months.
📌 Clinical Tip: While early treatment is ideal, short delays don’t compromise long-term vision—important in cases where steroid use must be cautious.
📝 Summary Table
| Study Focus | Intervention | Outcome |
|---|---|---|
| Stromal keratitis | Topical steroids + antivirals | ✅ Effective |
| Stromal keratitis | Oral aciclovir + topical therapy | ❌ No added benefit |
| Iridocyclitis | Oral aciclovir + topical steroid | ⚠️ Modest benefit |
| Recurrence prevention | Oral aciclovir prophylaxis | ✅ Reduces recurrence |
| Predictors of recurrence | Disease history | ✔️ Prior stromal = high risk |
| Risk factors | Lifestyle/Environmental | ❌ Not significant |
📚 Final Thoughts
The HEDS trials are the gold standard in understanding HSV keratitis management. Their data demystified longstanding debates and helped clinicians choose evidence-based treatments. Whether you’re preparing for your FRCOphth exam or managing a complex corneal case, HEDS remains your trusted guide.