Understanding Herpes simplex eye disease (HSV keratitis)
Herpes simplex remains in the body after initial infection and can reactivate. Many people have no eye disease, while some experience recurrent episodes affecting the surface epithelium, deeper corneal stroma or other eye structures. A history of cold sores alone does not diagnose the cause of a red eye. [1] [2]
Repeated inflammation or infection can scar the cornea and alter its optical quality, sometimes affecting vision between episodes. Treatment aims both to control an active episode and, in selected people, reduce recurrences. Antiviral treatment suppresses viral activity but does not remove latent virus from the body. [2] [3]
One condition. Different experiences.
Explore different selected symptom features, then read how they may vary. These examples are not stages or a clinical test.
Original VisualSim schematic illustrations, informed by the cited clinical descriptions. These are not study figures, patient recordings or validated severity levels.
Pain, watering and light sensitivity
A red, watery eye may hurt or be difficult to keep open in light. These symptoms overlap with other corneal problems and require examination rather than a diagnosis from symptom matching. [1] [2]
Blur or glare
Active surface damage, swelling or residual scars can reduce clarity and cause irregular optical effects. A blur slider illustrates only selected visual consequences, not the infection itself or its activity. [2] [3]
Recurrence can feel different
Later episodes may be less painful if corneal sensation is affected. A surface defect in a previously infected eye may also reflect poor nerve-related healing rather than straightforward active viral replication. [1] [3]
The corneal layer changes the treatment question
Original educational diagram; the branches are clinical distinctions, not stages every patient must pass through. [3] [5]
Original VisualSim teaching diagram · © VisualSim. Clinical basis in linked sources; not a published study figure. Image provenance.- Epithelium
Active surface viral disease needs an antiviral approach.
- Stroma
Deeper inflammation can need supervised anti-inflammatory treatment with antiviral coverage.
- Healing
Reduced sensation and scarring may require a separate recovery plan.
What is happening—and what remains uncertain
After infection, herpes simplex can remain latent in sensory nerve tissue and later reactivate in the eye. Surface epithelial disease reflects a different balance of viral activity and tissue involvement from immune-mediated stromal inflammation. This distinction changes whether anti-inflammatory treatment is appropriate. [2] [3]
Damage to corneal nerves can reduce sensation and impair epithelial healing. Scarring and new vessels can add longer-term optical problems. A persistent ulcer despite treatment therefore prompts reassessment for healing failure, drug toxicity, resistance or another organism, not automatic escalation of the same prescription. [3]
What can look similar?
Epithelial versus stromal disease
Antiviral treatment is central to active epithelial HSV disease. A steroid can be useful for selected stromal inflammation with antiviral coverage, but can worsen an untreated epithelial infection; the layer and activity matter. [3] [5]
Herpes zoster ophthalmicus
Shingles affecting the eye is due to varicella-zoster virus, not herpes simplex. The 2025 ZEDS trial concerns selected adults with shingles-related eye inflammation and should not be treated as another HSV trial. [6]
Neurotrophic or other surface disease
A persistent defect in a previously infected cornea may be neurotrophic, toxic or due to a different infection. Contact-lens-associated Acanthamoeba is an important mimic; a history of HSV cannot exclude it. [3]
Similar-looking symptoms can have different causes. A matching picture cannot establish a diagnosis.
What an assessment may involve
- Examine the involved layerA slit-lamp examination with staining helps identify an epithelial pattern and assess stromal inflammation, swelling and any anterior-eye involvement. The clinician may check corneal sensation and pressure as well as acuity. [2] [3]
- Use tests when the pattern is uncertainTypical disease is often diagnosed clinically, while selected atypical or nonresponding lesions need swab or scrape testing. The usefulness of PCR depends on the disease layer, timing and prior treatment; a blood antibody result cannot by itself establish the cause of the current ulcer. [3]
- Review recurrence and medicinesBring dates of earlier episodes, prior laboratory confirmation, surgery and all drops or tablets used. Tell the clinician about immune suppression and relevant medical conditions, so treatment and any prevention plan can be tailored safely. [1] [3]
What may help—and what is still being studied
Treat the active episode appropriately
Antivirals may be topical or oral depending on the findings and local practice. Follow the actual prescription and review plan; do not stop as soon as pain improves or use another person’s medicine. Antibiotic drops alone do not treat HSV. [1] [2]
Steroids require a specific rationale
In the HEDS stromal trial, supervised steroid treatment with antiviral coverage controlled inflammation better than placebo. This does not establish safety for every ulcer: never transfer the plan to active epithelial disease or another undiagnosed infection. Pressure and tapering need clinical supervision. [3] [5]
Discuss prevention and residual damage
Longer antiviral suppression can reduce recurrences in selected people, particularly with prior stromal disease. It is not a permanent cure, and duration, medical suitability and breakthrough episodes need review. Scarring or poor healing may require specialist surface care or a separate surgical discussion. [3] [4]
What this can mean for daily life
Keep a rapid-contact plan
Save the eye clinic’s number and ask how to obtain review for a suspected recurrence. Recognizing an early change and knowing where to go is more useful than repeatedly comparing the eye to online photographs. [1] [2]
Follow lens and hygiene guidance
Do not wear contact lenses during active symptoms; ask when your own cornea is safe for resumption. Wash hands and avoid touching an active cold sore and then the eye. The diagnosis should not be a source of shame or assumptions about sexual transmission. [1] [2]
Bring a clearer description to your appointment
Choose the questions you want to discuss. These choices stay in this page’s memory.
Research, with the context left in
Selected studies and guidance, with their populations and limitations. These are curated educational summaries, not a complete systematic review or a formal evidence rating.
HEDS antiviral recurrence-prevention trial
Ocular recurrence during treatment was less frequent with acyclovir; the benefit was particularly important in people with previous stromal disease. [4]
Limits and applicability: Selected prior-disease population and finite follow-up; suppression reduced rather than eliminated recurrence and did not eradicate latent virus.
HEDS topical corticosteroid trial for stromal keratitis
Steroid treatment reduced persistent or progressive stromal inflammation and shortened resolution. [5]
Limits and applicability: Older trial of a specific disease layer and supervised regimen. It does not justify unsupervised steroid use for epithelial HSV or all red eyes.
Zoster Eye Disease Study: a related but distinct infection
The 12-month primary endpoint was not statistically significant; secondary 18-month and repeated-episode outcomes favored treatment. [6]
Limits and applicability: VZV rather than HSV; selected kidney-function and other eligibility criteria limit transfer to all patients. Secondary results must not be reported as a positive primary endpoint.
Questions researchers still need to answer
- Which recurrence patterns justify longer suppression while minimizing resistance, toxicity and treatment burden?
- How can clinicians best distinguish active virus from neurotrophic healing failure in nonresponding disease?
Trusted places to go next
Selected clinical references, research, practical support and ways to connect. Official pages checked 24 October 2026; each entry explains its scope and region.
NHS — herpes simplex eye infections
Clear symptom, urgent-care and treatment explanation without requiring an account.
National Eye Institute — HEDS research explanation
Explains the original prevention trial; historical 1998 evidence, not a current individualized dosing plan.
American Academy of Ophthalmology — herpes keratitis
Current patient explanation of herpes simplex eye disease and clinician-directed care.
Dry Eye Foundation — ocular-surface support
Broader practical and emotional support for persistent surface symptoms; not a dedicated HSV treatment group or urgent-care service.
Connections listed by the organization.
Questions you may still have
Is this the same virus as shingles?
No. Herpes simplex and varicella-zoster are different viruses. Both can affect the eye, but their evidence and prevention pathways differ. [2] [6]
Do steroids always make herpes worse?
No blanket rule is accurate. They can worsen inappropriate untreated epithelial infection, while supervised steroid treatment with antiviral coverage benefits selected stromal inflammation. The examination determines which situation applies. [3] [5]
Sources, image credits and review status
Compiled by VisualSim from clinical references and published research. Sources checked 24 October 2026. Independent clinical review has not been recorded; no named clinical reviewer or clinical validation is claimed. Research evidence and its limitations are linked below.
- NHS — Herpes simplex eye infections (n.d.; institution).
Relevant page content and scope checked; source verification is not independent clinical review.
Checked 2026-10-24 · Public page checked - AAO — Herpes Eye Infections: What is Herpes Keratitis? (2026; institution).
August 13, 2026 indexed patient text read; direct client 403. Avoided outdated or generalized prevalence statements.
Checked 2026-10-24 · Public page checked - Sibley and Larkin — Update on Herpes simplex keratitis management (2020; review).
Indexed clinical and diagnostic sections read; full-page publisher direct request unavailable. Source publication is 2020, not PMC collection year.
Checked 2026-10-24 · Full text checked - Herpetic Eye Disease Study Group — Acyclovir for prevention of recurrent HSV eye disease (1998; trial).
Relevant page content and scope checked; source verification is not independent clinical review.
Checked 2026-10-24 · Abstract/indexed material checked; complete full-text review not claimed - Wilhelmus et al. — Controlled trial of topical corticosteroids for HSV stromal keratitis (1994; trial).
Relevant page content and scope checked; source verification is not independent clinical review.
Checked 2026-10-24 · Abstract/indexed material checked; complete full-text review not claimed - Cohen et al. — Zoster Eye Disease randomized clinical trial (2025; trial).
Relevant page content and scope checked; source verification is not independent clinical review.
Checked 2026-10-24 · Abstract/indexed material checked; complete full-text review not claimed - Dry Eye Foundation — You are not alone (n.d.; institution).
Relevant page content and scope checked; source verification is not independent clinical review.
Checked 2026-10-24 · Public page checked
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