Herpes Simplex Keratitis: Causes, Symptoms, and Treatment
What Is Herpes Simplex Keratitis?
Understanding what HSK is and how it behaves helps explain why it needs careful, ongoing management rather than a simple course of eye drops. The virus behind this condition has unique characteristics that set it apart from most other eye infections.
HSK develops when the herpes simplex virus, most often type 1, infects the cornea. This virus lives inside nerve tissue and can travel to the eye even if you have never had a visible cold sore or any obvious herpes outbreak. Once it reaches the cornea, it can damage the cells on the surface or in deeper layers of the eye, and it may strike for the first time or reactivate from a dormant state in your nerves.
Unlike pink eye (conjunctivitis), which affects the clear membrane lining the white of the eye and inner eyelids, HSK targets the cornea itself. Pink eye often resolves on its own or with simple treatment, while HSK requires antiviral medication and close follow-up. HSK can cause corneal scarring and vision loss, which typical pink eye does not. Redness from HSK is often most visible around the colored part of the eye rather than spreading evenly across the white.
Not all cases of HSK look or behave the same. The type of keratitis depends on which layer of the cornea is affected, and this distinction guides treatment decisions.
- Epithelial keratitis affects only the outermost layer of the cornea and often creates a distinctive branching, tree-like pattern called a dendritic ulcer
- Stromal keratitis penetrates deeper into the middle layers and carries a greater risk of scarring and permanent vision changes
- Immune stromal keratitis involves inflammation without active virus in the tissue, while stromal necrosis is a rarer and more severe form
- Endotheliitis, sometimes called disciform keratitis, affects the deepest corneal layer and can cause swelling and clouding
- HSV infection can also trigger inflammation inside the eye called anterior uveitis, which may raise eye pressure
A geographic ulcer is a larger, irregularly shaped epithelial defect that can also occur with HSV. Identifying the exact type of HSK is essential because treatment differs significantly between forms.
After the first episode, the herpes simplex virus does not leave your body. It hides quietly in nearby nerve tissue and can remain dormant for months or years before reactivating. Each recurrence increases the risk of deeper corneal damage and lasting vision changes, which is why long-term management is often part of the treatment plan.
Recognizing the Symptoms of HSK
The symptoms of HSK can range from mild irritation to serious discomfort and vision changes. Recognizing them early and seeking care promptly makes a meaningful difference in outcomes.
Pain in or around the affected eye is common with HSK, though the intensity varies. In some cases, the virus reduces corneal sensation over time, which means you may feel less pain than expected even when the infection is active. Redness tends to be most noticeable around the colored part of the eye, a pattern called limbal or ciliary injection. Excessive tearing is also common as the eye tries to respond to the infection.
Many people with HSK find bright lights uncomfortable or painful, a symptom called photophobia. You may prefer dim rooms or feel the need to wear sunglasses even indoors. Blurred vision can develop from swelling and inflammation in the cornea and may start mild but worsen as the infection progresses without treatment.
A scratchy, gritty sensation is a common complaint with HSK, even when nothing is physically in the eye. This foreign body feeling comes from damage to the corneal surface and can be persistent and distracting.
- The sensation may feel constant or get worse with each blink
- It often mimics the feeling of sand or an eyelash trapped under the eyelid
- Rubbing the eye will not provide relief and may worsen the damage
- It typically affects only one eye at a time
Some symptoms point to a more serious infection or complication and require same-day evaluation. Do not wait to be seen if you experience sudden or severe vision loss, intense eye pain that does not ease, or visible white or cloudy patches on the cornea. Additional urgent warning signs include halos around lights combined with eye pain, severe headache or nausea alongside eye symptoms, or being unable to keep the eye open due to pain or light sensitivity.
If you wear contact lenses and develop significant pain, redness, light sensitivity, or vision changes, seek care immediately. Patients with a weakened immune system should also pursue urgent evaluation for any new eye symptoms, as infections can progress more rapidly in those cases.
Who Is at Risk for Herpes Simplex Keratitis?
Certain people are more likely to develop HSK or experience recurrent episodes. Knowing your risk factors helps you stay alert for early symptoms and communicate important history to your eye care provider.
If you have ever had cold sores around your mouth or nose, you carry the herpes simplex virus and are at risk for eye involvement. The virus can travel along nerve pathways and reach the cornea even when cold sores are not active. People with a history of genital herpes, typically caused by type 2, can also develop corneal infections, though this is less common than with type 1.
Conditions or medications that reduce immune function make it easier for the herpes virus to reactivate. If your body cannot keep the virus in check, recurrences become more likely and can be more severe.
- Organ transplant recipients taking anti-rejection medications
- Patients undergoing chemotherapy or radiation
- People living with HIV or other immune disorders
- Those taking high-dose corticosteroids for other health conditions
Eye injury or surgery can sometimes trigger reactivation of the herpes virus in people who already carry it in their nerve tissue. Procedures such as LASIK or cataract surgery may lead to reactivation in susceptible patients. Contact lens wearers face a higher baseline risk of various corneal infections, and poor lens hygiene can create opportunities for infections to take hold. If you have a history of HSV, our team will take extra care to discuss lens safety with you.
Physical or emotional stress can lower your body's defenses and allow the virus to reactivate. Fever, severe illness, prolonged sun exposure, and lack of sleep have all been identified as potential triggers. Many patients notice that their HSK episodes cluster around periods of high stress or other illnesses. Identifying your personal triggers can help you stay alert for early warning signs.
How We Diagnose Herpes Simplex Keratitis
Accurate diagnosis is essential before any treatment begins, because using the wrong medication for the wrong type of corneal infection can cause serious harm. Our cornea specialists, including Dr. Jane Cook, Dr. Christopher Newton, and Dr. Elliot Perlman, use a careful combination of your history and specialized examination to reach a precise diagnosis.
We start by asking about your symptoms, when they began, whether you have had similar episodes before, and whether you have a history of cold sores or herpes infections. Your answers guide the focus of our examination. We then assess your vision, check eye pressure, and evaluate all the structures of your eye for signs of inflammation or damage.
Fluorescein is a safe orange dye that we place on the surface of your eye. Under a special blue light, it glows bright green and highlights areas of corneal damage. Using a slit lamp microscope, we look for the distinctive branching, tree-like pattern called a dendritic ulcer, which is a hallmark sign of epithelial HSK. This appearance often allows us to confirm the diagnosis without laboratory testing.
Most cases of HSK are diagnosed based on the clinical appearance of the cornea alone. Laboratory testing is typically reserved for atypical presentations, severe or recurrent infections, treatment-resistant cases, or situations where the diagnosis is genuinely uncertain, particularly in immunocompromised patients.
- Polymerase chain reaction (PCR) testing for rapid and accurate virus detection
- Viral culture to grow and identify the virus, though this method takes longer
- Corneal scraping to examine cells under a microscope
- Anterior segment imaging to assess stromal swelling or scarring when needed
Several other serious conditions can mimic HSK, and we take care to consider them before beginning treatment. Bacterial keratitis, including infections caused by Pseudomonas, is especially common in contact lens wearers. Acanthamoeba keratitis is a serious infection also linked to lens use and water exposure. Varicella zoster virus can produce corneal inflammation with patterns similar to HSV. Fungal infections and autoimmune conditions affecting the cornea are also in our consideration. Applying steroid drops to an eye with undiagnosed infectious keratitis can cause rapid, serious worsening, so getting the diagnosis right first is a priority we never skip.
Treatment Options for Herpes Simplex Keratitis
Treatment for HSK is tailored to the type and severity of your infection. The goal is to eliminate active virus, control inflammation, prevent complications, and reduce the chance of future recurrences.
Antiviral medications are the foundation of HSK treatment. Depending on the form and severity of your infection, we may recommend topical drops or gel applied directly to the eye, oral antiviral pills, or a combination of both.
- Topical ganciclovir gel or trifluridine drops for epithelial disease, where available
- Oral acyclovir, valacyclovir, or famciclovir for deeper disease, recurrent infections, or use in immunocompromised patients
- Long-term suppressive oral antiviral therapy to prevent recurrences in patients with frequent or severe episodes
- Dose adjustments for patients with kidney disease when oral antivirals are needed
Antibiotic drops do not treat HSV and are not part of standard HSK therapy. They may be added only if there is concern for a secondary bacterial infection alongside significant surface breakdown.
Corticosteroid eye drops reduce inflammation and can help prevent scarring in certain forms of HSK. However, steroids are generally avoided during active epithelial HSV keratitis because they can allow the virus to spread and significantly worsen the infection. For stromal keratitis, endotheliitis, or anterior uveitis caused by HSV, we may carefully add corticosteroid drops alongside antiviral coverage and close monitoring. The timing, dose, and duration of steroid use is individualized for each patient and must be supervised by an ophthalmologist. You will need regular follow-up visits to monitor eye pressure and ensure the virus is not reactivating while on steroids.
In some cases of epithelial keratitis, we may gently remove infected cells from the corneal surface using a sterile instrument. This technique, called debridement, reduces the viral load on the eye and can speed healing. The procedure is performed in the office with numbing drops and is followed by antiviral treatment. Most patients tolerate it well and begin to notice improvement within a few days.
Stromal keratitis that is severe or keeps coming back requires a more involved treatment approach and careful long-term monitoring.
- Extended courses of oral antiviral therapy to suppress the virus
- Slow, gradual reduction of steroid drops to avoid rebound inflammation
- Medications to control eye pressure if needed
- Management of neurotrophic keratopathy, a condition where repeated nerve damage reduces corneal sensation and impairs healing, using lubrication and surface support
- Long-term suppressive antiviral therapy to reduce future episodes and protect vision
- Corneal transplant surgery in cases where scarring has severely and permanently reduced vision
Caring for Your Eyes During and After Treatment
What you do between appointments matters. Good habits during recovery support healing, reduce the risk of secondary infection, and lower the chance of bringing the virus back sooner than it otherwise might return.
Simple hygiene and protective measures make a real difference during recovery. Wash your hands thoroughly before and after applying eye drops, and resist the urge to touch or rub your eyes no matter how uncomfortable they feel.
- Use a clean tissue to gently blot excess tearing
- Avoid eye makeup until the infection has fully cleared
- Wear sunglasses outdoors to manage light sensitivity
- Get adequate rest and stay well hydrated to support your immune system
- Do not wear contact lenses until cleared by your eye care provider, and discard any lenses or lens cases used around the time of infection
- Never use leftover steroid drops or numbing drops on your own at home
- Do not patch the eye unless specifically directed by your provider
- Avoid sharing eye drops, towels, or washcloths to prevent spreading the virus
Even when symptoms improve quickly, it is essential to finish the full prescribed course of antiviral medication. Stopping early can allow the virus to resurge, leave the healing incomplete, and increase the risk of recurrence or disease progression. If side effects are bothering you, contact our office rather than stopping on your own. We can often adjust the dose or find an alternative that works better for you.
We will schedule follow-up appointments to monitor how well your cornea is healing and catch any complications early. The frequency of visits depends on the severity of your infection. Mild epithelial disease may only require one or two check-ins, while stromal keratitis often calls for closer monitoring over several weeks or months. If you notice new symptoms or worsening vision between appointments, reach out to us right away rather than waiting for your next scheduled visit.
Because the herpes virus stays in your body permanently, preventing recurrences is an ongoing part of your care plan. Managing stress, protecting your eyes from injury, getting enough sleep, and maintaining overall health all help keep the virus dormant. For patients with frequent or severe recurrences, we may recommend long-term suppressive antiviral therapy, which can significantly reduce the number and severity of future episodes.
Frequently Asked Questions
These answers address questions that go beyond what is covered above, offering additional guidance to help you make informed decisions about your care.
Direct contact with secretions from the infected eye can spread the herpes simplex virus, so hygiene is genuinely important. Touching your infected eye and then touching your other eye is the most common way people spread HSK to themselves, so making a conscious habit of not touching your eyes and washing your hands frequently is the single most effective preventive measure. Spreading the virus eye-to-eye to another person is less common in everyday situations but is possible through shared towels or direct contact with active secretions. Avoiding shared linens and practicing careful hand hygiene protects both you and the people around you.
A single episode of epithelial HSK treated promptly and appropriately often heals without lasting vision problems. The greater risk comes from repeated infections and stromal keratitis, both of which can cause progressive corneal scarring that permanently blurs vision. Neurotrophic changes from repeated nerve damage and complications from prolonged treatment can also affect long-term outcomes. The most important factors in protecting your vision are starting treatment early, attending all follow-up visits, and following through with any recommended suppressive therapy.
Uncomplicated epithelial keratitis typically heals within one to two weeks with consistent antiviral treatment. Stromal keratitis is more variable and often takes several weeks to months, depending on how deeply the cornea is involved. Your personal healing timeline will depend on how quickly treatment began, the severity and type of your infection, and whether any complications develop along the way. If your symptoms are not improving as expected, let us know so we can reassess your treatment plan.
Contact lens wear is generally not recommended during an active infection or in the immediate recovery period. Once your cornea has fully healed and we have confirmed the infection is resolved, lens wear may be possible again, though with added precautions. Some patients do better long-term by switching to daily disposable lenses, which reduce the risk of lens-related complications, while others may find that glasses are a more comfortable and lower-risk option going forward. This is a conversation best had at your follow-up visit once healing is confirmed.
As of now, there is no approved vaccine to prevent herpes simplex virus infection or its recurrence in the eye, though research is ongoing. There is also no treatment that completely eliminates the virus from your body. What we do have are effective antiviral medications that control the infection when it is active, and long-term suppressive therapy that can meaningfully reduce how often the virus reactivates. Most people with HSK are able to maintain good vision and quality of life with appropriate management.
Any sudden change in vision, intense eye pain that does not ease, a visible white or cloudy area on the front of the eye, or the sensation that your eye has been chemically burned should prompt same-day evaluation, not a wait-and-see approach. This is especially true for contact lens wearers and for anyone with a known history of HSK, because the window for effective intervention can be narrow. If you are immunocompromised and develop any new eye symptoms, treat them as urgent even if they seem mild at first.
Expert Care for Herpes Simplex Keratitis at Rhode Island Eye Institute
At Rhode Island Eye Institute, our fellowship-trained cornea specialists have the expertise and diagnostic technology to accurately identify and treat all forms of herpes simplex keratitis, from mild epithelial disease to complex stromal cases. If you are experiencing eye pain, redness, light sensitivity, or blurred vision, we encourage you to contact us promptly so we can evaluate your eye and begin protecting your vision right away. Early, expert care makes a lasting difference in outcomes for this condition, and our team is here to guide you through every step of treatment and recovery.