What is Herpes Simplex Ophthalmicus?
Herpes simplex ophthalmicus (HSO) is an eye infection caused by the herpes simplex virus type 1 and type 2. This virus can affect all parts of the eye. The first infection often happens in the form of an inflammation of the eyelids and the membrane that covers the white of the eye. This typically occurs in newborns through transmission during birth, and in children through contact with oral or facial mucus.
This first infection usually gets better on its own, and the virus travels up through the nerves in the skin to become dormant, or “hidden”, in a cluster of nerves in the face called the trigeminal nerve ganglion. If the body’s immune system becomes weak or compromised, the virus can wake up and cause a second infection in different parts of the eye such as the eyelids, the thin layer in front of the white of the eye, the cornea (the clear front surface of the eye), the middle layer of the eye (uvea), and occasionally the retina (the layer at the back of the eyeball).
Antiviral medications, which can be applied directly to the eye (topical) or taken by mouth (systemic), are typically used to treat this condition. However, if the infection is severe, it can often cause serious damage to the eyesight. Once a person has suffered from this infection, the virus remains in the body for life.
What Causes Herpes Simplex Ophthalmicus?
Herpes Simplex Ophthalmicus, or eye herpes, is caused by a tricky double-stranded DNA virus. This virus involves two main types that affect humans – Herpes Simplex Virus type 1 (HSV-1) and Herpes Simplex Virus type 2 (HSV-2). HSV-1 mostly causes oral and eye infections that can be spread by contact with an infected person, while HSV-2 is responsible for genital infections, typically spread through sexual contact. Unfortunately, newborns can get HSV-2 during birth from a mother with the infection, and children can also get it from adults.
In babies, the primary infection shows up as a condition called ophthalmia neonatorum. In kids under five, it appears as blepharoconjunctivitis, an inflammation of the outer parts of the eye. The sneaky virus travels up the skin nerves to hide out in a cluster of nerve cells near the cheekbone, called the trigeminal ganglion. Certain factors, like fever, stress, periods, and certain medications or conditions that affect the immune system, can trigger the virus to reactivate, leading to secondary infections in adults. Recurring infections usually present as dendritic keratitis, which affects the eye’s cornea.
Risk Factors and Frequency for Herpes Simplex Ophthalmicus
Herpes simplex ophthalmicus is a common eye infection that is usually present in adults by their later years. The most frequent cause of corneal blindness in developing countries is a specific form of this condition known as HSV keratitis. Globally, herpes simplex virus (HSV) affects 60-95% of all adults. However, HSV-1, a type of herpes, is more common among people in low socioeconomic groups, affecting 70-80% of such individuals, compared to 40-60% in the higher socioeconomic groups.
In the United States, for instance, infection with HSV is present in one out of every 3200 newborns, leading to around 1500 cases annually. The country also reports a total of 400,000 cases of HSV keratitis. Each year, 58,000 episodes of this condition are documented, out of which roughly 24,000 are new cases.
Unfortunately, the infection tends to come back frequently in the same patients. After one year, an estimated 27% of patients may have a recurrence, and the rate goes up to over 60% after 20 years. Though recurrent diseases more often cause keratitis, they can affect all parts of the eye as well.
Signs and Symptoms of Herpes Simplex Ophthalmicus
Herpes simplex ophthalmicus is an eye infection that usually happens in a person with no immunity to the herpes simplex virus. This infection can be transmitted to newborn babies during birth or to children through contact with a cold sore. Adults can also get this infection through sexual contact. Here is how this can present in different scenarios:
- In-utero HSV infection: A baby can get infected while still in the womb due to a genital infection or via the placenta. These babies are usually born with eye problems like cataracts and chorioretinitis.
- Neonatal conjunctivitis: This infection happens through the birth canal and is usually caused by the HSV-2 virus. It generally shows up between 3-15 days after birth, often with signs like vesicles on the eyelids. The infection can lead to inflammation of the eyes and can sometimes result in issues like a cataract, vitritis, retinitis, retinal detachment, or optic neuritis.
A primary herpes simplex conjunctivitis, similar to pink eye, typically happens in children younger than five years old. The condition causes a watery discharge from the eyes, follicular conjunctivitis, preauricular lymphadenopathy (swelling of the lymph nodes near the ear), and a rash of small blisters around the eyelids. The infection is mostly caused by the HSV-1 virus. Lesions (damaged tissues) are widespread and will shed the virus for up to ten days. The condition generally resolves within two to three weeks.
Recurrent herpes simplex ophthalmicus is when the dormant (silent) virus in the nerve cells of the face becomes active again. This can present as blepharoconjunctivitis, with symptoms like focal vesicles along the eyelid, watery discharge, follicular conjunctivitis, and preauricular lymphadenopathy.
There are other forms of this infection, such as epithelial keratitis, which starts as tiny opaque spots on the surface of the eye due to the active virus. These spots can then blur together and peel off centrally. This process might be signaled by mild irritation, redness, watering, light sensitivity, and a diminished sense of touch for the cornea.
There are various other types of eye complications that can occur as a result of the herpes simplex virus, including endotheliitis (inflammation of the inner layer of the eye), metaherpetic keratitis (an ulcer from nerve damage), marginal keratitis, necrotizing stromal keratitis (which causes serious inflammation reaction to viral replication), and keratouveitis (inflammation of the cornea and the uvea, the middle layer of the eye). These complications can cause a range of symptoms such as eye pain, redness, blurred vision, and others. If diagnosed and treated promptly, eye damage can be minimized and sight can be preserved.
Additionally, herpes simplex can cause or be associated with episcleritis and scleritis (inflammation of the white part of the eye), epidemic keratoconjunctivitis, erythema multiforme major (a type of hypersensitive reaction that affects the skin and sometimes the eyes), and iridocorneal endothelial (ICE) syndromes. Remember, early diagnosis and treatment can help prevent complications and preserve vision.
Testing for Herpes Simplex Ophthalmicus
Herpes simplex infection is typically identified through the distinct characteristics it presents, usually observed in a clinical examination or with a tool known as a slit lamp. If these typical signs fail because of factors like medication side effects, weakened immune system, or the use of multiple drugs, laboratory tests are utilized to make the diagnosis.
Different lab tests can confirm the presence of Herpes simplex. Here are some of them:
– Culture: This is a test where the virus is grown in the lab and usually reveals a result in two days. However, a particular dye known as rose bengal can interfere with the results as it kills the virus. The cells can also be stained to distinguish between different types of herpes infection.
– Direct Fluorescent Antibody (DFA) Testing: This is a quick test but doesn’t always give correct results. It involves spreading a sample on a slide and can give results in minutes. However, it needs a trained technician and special equipment. The sample is stained using a fluorescent antibody to reveal herpes infection. Yet another dye, fluorescein, can interfere with the results.
– Polymerase Chain Reaction (PCR) Testing: PCR test attempts to identify herpes virus DNA and is preferred for ocular (relating to the eye) herpes tests. It outstands virus culture in identifying specific eye inflammation due to herpes infection. Modern PCR tests are even able to differentiate between the virus being present and it multiplying.
– Tzanck Smear: This involves taking scrapings from the eyes or from skin blisters and staining them. It is a quick, inexpensive test, but doesn’t always give accurate results. It also can’t differentiate between different types of herpes.
– Cytology: A quick, inexpensive test which uses cells taken from the surface layer of the eye or skin using a brush.
– ELISA (Enzyme-linked Immunosorbent Assay): This test uses antibodies to detect the herpes virus and gives quick results.
– Serum Antibody Testing: This test looks for immune response against the herpes virus in a person’s blood. A positive result shows that the person’s immune system is reacting to the virus infection. But since most adults would test positive due to previous exposure to the virus, antibody testing is of limited use. In children and infants, it’s even less done as most herpes cases can be confirmed through examination.
Treatment Options for Herpes Simplex Ophthalmicus
Antiviral medicine is the primary treatment for viral infections of the eye’s outer layer. These medicines interfere with the virus’s ability to replicate by obstructing a specific enzyme (viral DNA polymerase). Acyclovir and Ganciclovir are commonly used antiviral medicines because they target specific enzymes and are less harmful to the body. They can be applied as an eye ointment or gel up to five times a day, or taken in pill or injection form.
When treating certain types of eye inflammation (stromal keratitis and Keratouveitis), corticosteroids are often used alongside antiviral medicine.
In newborns with eye inflammation, injection of Acyclovir is usually needed for approximately two weeks. If the infection has spread to the nervous system, treatment may need to be extended to three weeks.
To prevent a pregnant woman with an active, recurrent genital viral infection from passing the virus to her baby at birth, she may be given oral acyclovir treatment daily starting from 36 weeks of pregnancy, and might need a cesarean delivery before her water breaks.
For viral ulcers and eye inflammation associated with eye and eyelid infection, treatment involves antiviral eye ointment or gel. Some patients may also need over-the-counter artificial tears.
When treating disciform keratitis, a type of eye inflammation, steroid eye drops along with antiviral medicine are used for about ten weeks.
In cases of resistant eye inflammation, the main goal of treatment is to eliminate the underlying cause, such as toxicity. If the eyes are dry, artificial tears might be necessary, and in severe cases, an operation may be required.
When treating inflammation of the cornea and surrounding tissue, steroid drops are used along with antiviral medication. There is also an oral version of Acyclovir taken twice daily for six months to a year to avoid recurring infection.
Frequently, surgery is an option for severe scarring, ulcers that won’t heal, or high risk of rupture. Surgeries could include implanting a donated cornea, applying certain adhesives to secure a hole in the cornea, or using natural materials to aid healing. It’s crucial to note that long-term use of antiviral medication is typically necessary after these procedures to avoid recurrent infections.
What else can Herpes Simplex Ophthalmicus be?
When diagnosing certain eye conditions, doctors need to take into account several other illnesses that often exhibit similar symptoms. They’re outlined below for each of these conditions:
For “Ophthalmia Neonatorum” (eye inflammation in a newborn), doctors might consider:
- Keratitis (inflammation of the cornea)
- Dacryocystitis (infection in the tear duct)
- Congenital nasolacrimal duct obstruction (a blockage in the tear duct at birth)
- Congenital glaucoma (a condition a baby is born with that causes high pressure within the eye)
- Orbital and pre-septal cellulitis (infections of the tissues around the eye)
If someone may have “HSV Keratitis” (a form of eye inflammation caused by the herpes virus), these conditions could also be considered:
- Herpes zoster keratitis (eye inflammation caused by the chickenpox virus)
- Microbial keratitis (inflammation caused by bacteria, viruses, or fungus)
- Adenoviral keratitis (inflammation caused by common cold viruses)
- Acanthamoeba keratitis (inflammation caused by a parasite)
- Drug toxicity
- Epithelial regeneration line
- Chronic contact lens wear
For “HSV Stromal/Interstitial Keratitis” (a type of eye inflammation caused by the herpes virus that occurs deeper in the cornea), the doctor might consider:
- Varicella-zoster keratitis (another type of eye inflammation caused by the chickenpox virus)
- Epstein-Barr virus keratitis (inflammation caused by the virus that causes mono)
- Measles keratitis (inflammation due to the measles virus)
- Mumps keratitis (inflammation due to the mumps virus)
- Cogan’s syndrome (a rare vascular condition)
- Syphilis
- Lyme’s disease
In the case of “Corneal Hypesthesia” (corneal insensitivity), these conditions could be considered:
- Herpes virus keratitis
- Chronic contact lens wear
- Lesions caused by an acoustic neuroma, surgery, or trauma on the Trigeminal nerve (that transmits sensations from the face to the brain)
- Diabetes
- Use of certain topical medications (anesthetics, beta-blockers, and nonsteroidal anti-inflammatory agents)
- Laser eye surgery
What to expect with Herpes Simplex Ophthalmicus
Ophthalmia neonatorum and primary blepharoconjunctivitis, two eye conditions, are known to respond well to antiviral treatments and usually have a positive outcome with few complications. HSV epithelial keratitis, a disease affecting the cornea of the eye, can also be resolved within 1 to 2 weeks using topical antiviral treatments.
However, 25% of the people affected with this condition may experience stromal keratitis and iritis. These conditions often come back and can result in corneal scarring, glaucoma, neovascularization, and corneal melting, all of which can lead to permanent vision loss.
Reports from the Australian corneal graft registry show that 4% of their graft failures are a result of HSV ophthalmicus, an infection of the eye caused by the herpes simplex virus.
On the other hand, acute retinal necrosis, a severe inflammation of the retina, has a poor vision prognosis. Research shows that 64% of affected eyes end up with a vision of 20/200 or worse. This is mainly due to severe complications such as retinal detachment, optic neuropathy, macular edema, and retinal ischemia.
Possible Complications When Diagnosed with Herpes Simplex Ophthalmicus
There are a range of potential complications that can occur in certain eye conditions. These include:
- Infectious keratitis
- Dense corneal stromal scarring
- Chronic dry eye
- Chronic uveitis
- Corneal melting
- Corneal neovascularization
- Persistent epithelial defect
- Secondary glaucoma
- Complicated cataract
- Posterior synechiae
- Peripheral anterior synechiae
- Chronic vitritis with vitreous condensation and floaters
- Retinal detachment, optic neuritis, cystoid macular edema, and retinal ischemia in patients with acute retinal necrosis
Preventing Herpes Simplex Ophthalmicus
Educating both patients and their caregivers about the severe visual impact of HSV keratitis (a type of eye infection caused by the herpes simplex virus) and the importance of following the treatment plan is vital. Since the herpes simplex virus is very common and nearly impossible to avoid, there are certain steps that can be useful in preventing the initial infection and the recurrence of the disease.
First, if a woman is pregnant and she is at the 36-week mark, taking preventive oral antiviral medicine and choosing a planned cesarean section can prevent the virus from being passed on to the baby during childbirth.
Second, adults should refrain from transferring the virus to newborns through kisses or other oral contact.
Third, taking oral antiviral medication over a long period can prevent recurring cases in corneal graft (a type of eye surgery) patients and those suffering from stromal keratitis and keratouveitis.
Finally, long-term consumption of oral antiviral medication can prevent the return of the disease in patients who had a corneal graft due to uncontrollable epithelial keratitis (a type of eye inflammation) or a dense scar tissue resulting from HSV keratitis.
