Herpes in the eye: Definition, symptoms, therapy

Herpes on the eye: brief overview

What is ocular herpes? Herpes simplex virus infection of the eye, most commonly on the cornea (herpes keratitis), but also elsewhere such as the eyelid, conjunctiva or retina; possible at any age, even in newborns
Symptoms: Ocular herpes usually occurs unilaterally, often with swelling on and in the eye, herpes blisters on the edge of the eyelid, red, painful, watery eyes, photophobia, foreign body sensation; in advanced stages, deterioration of vision (see an ophthalmologist immediately, blindness possible!)
Treatment: antivirals, in mild cases topically as ointment or drops, otherwise systemically as tablets, possibly glucocorticoids (“cortisone”), possibly corneal transplantation, rarely vitrectomy
Prevention: avoid close contact with acutely infected people, maintain strict hygiene (e.g. wash hands before contact with eyes, change towels), take care with contact lenses; in the case of recurrent inflammation, long-term prophylaxis with antivirals if necessary
Cure: A complete cure is not possible as herpes viruses remain in the body; frequent recurring outbreaks (recurrences) of ocular herpes
Possible complications: Recurrences, scars, persistent damage and clouding of the cornea, glaucoma, retinal detachment, superinfections with other germs (bacteria, other viruses, fungi), blindness
Examinations: performed by an ophthalmologist; the ophthalmologist checks corneal sensitivity and examines the eye using a slit lamp, ophthalmoscopy, fluorescein staining; virus detection is possible with PCR

What is ocular herpes?

Ocular herpes is an umbrella term for infectious diseases of the eye caused by herpes simplex viruses (HSV). The viruses usually infect the eyelid, iris, ciliary body, conjunctiva, cornea or retina on one side. There they inflame and damage the tissue.

Doctors distinguish between different forms of ocular herpes, depending on which part of the eye the viruses have affected:

Herpes simplex keratitis (herpes keratitis)

Herpes simplex keratitis is when herpes occurs on the cornea of the eye. It is the most common form of ocular herpes. It is estimated that there are around ten million sufferers worldwide.

The transparent cornea is located at the front of the eyeball in front of the pupil and consists of several layers. Herpes simplex viruses can infect any of them. Doctors therefore differentiate between

epithelial keratitis (keratitis dendritica): herpes affects the uppermost corneal layer
stromal keratitis (keratitis herpetica interstitialis): herpes viruses affect the middle layer of the cornea
endothelial keratitis (herpetic endotheliitis): ocular herpes affects the innermost layer of the cornea.

Herpes simplex conjunctivitis

The eyelid skin is often also affected. This is known as herpes simplex blepharoconjunctivitis. Doctors refer to the combination of conjunctivitis and corneal inflammation as herpes simplex keratoconjunctivitis.

Herpes simplex blepharitis

An initial infection with herpes often also manifests itself on the eyelid, known as herpes simplex blepharitis. Children are particularly frequently affected.

Herpes simplex uveitis anterior

This refers to herpes simplex virus infections in the anterior section of the middle part of the eye (anterior uvea). The iris, ciliary body or both are affected simultaneously (iridocyclitis).

Herpes simplex trabeculitis

In herpes trabeculitis, the trabecular meshwork near the outer edge of the iris becomes inflamed. The aqueous humor in the eye normally flows out via this spongy tissue. The inflammation disrupts the drainage and the intraocular pressure rises. This favors glaucoma, better known as glaucoma.

Herpes on the eye: acute retinal necrosis

In rare cases, the herpes simplex virus inflames the retina (herpes simplex retinitis) and its blood vessels. In the worst case, acute retinal necrosis occurs, in which retinal cells die. In this case, the disease often spreads to the second eye.

Acute retinal necrosis can cause blindness from ocular herpes.

Herpes neonatorum of the eye

When newborns become infected with the herpes simplex virus, this is referred to as herpes neonatorum. In many cases, HSV type 2 is the trigger, more rarely herpes simplex virus type 1.

This usually causes conjunctivitis (ophthalmia neonatorum) or corneal inflammation in the eye of the newborn. You can find out more about the transmission of herpes to the newborn and the symptoms and consequences in the article Herpes during pregnancy.

Herpes neonatorum often remains localized on the skin or eyes. However, it can also spread to the brain or the whole body and then become life-threatening. Doctors therefore treat it as soon as they suspect an infection.

Difference between ocular herpes and herpes zoster on the eye

In addition to the herpes simplex virus, there are other types of herpes virus that infect the eye. These include the varicella zoster virus (VZV). It causes shingles (herpes zoster), which can also occur in the eye. Doctors then speak of zoster ophthalmicus. You can find out more about this in our article “Shingles on the face”.

How does herpes manifest itself on the eye?

Symptoms of ocular herpes are often non-specific. This means that they also occur with other eye diseases. The symptoms that occur depend on where exactly herpes occurs on the eye.

Herpes symptoms on the eyelid

Painful, initially fluid-filled blisters: often in groups at the junction of skin and mucous membrane
Swelling of the eye, possibly also of the lymph nodes
burst herpes blisters with a crust after drying out
usually no scars

An outbreak of ocular herpes often begins with a burning or itching sensation in or around the eye. Early symptoms also include a swollen and reddened eyelid margin with a painful feeling of tightness.

Symptoms of herpes on the eye itself

Signs of other ocular herpes diseases such as herpes keratitis or herpes conjunctivitis mainly affect the eye itself. They are usually also limited to one side:

Red eye
Eye pain
Foreign body sensation
Shyness of light (photophobia)
Lacrimation

In the case of frequently recurring herpes and in severe cases, the following symptoms may also occur:

milky-greyish cloudy eye (due to clouding and scarring of the cornea, may only be seen by the doctor on examination)
Changed iris color or pupil shape (with herpes uveitis)
Deterioration of vision, restricted vision (visual field loss)
Loss of vision

If you experience any of these symptoms, see an ophthalmologist quickly. This will enable them to treat you in good time and prevent complications.

Symptoms of acute retinal necrosis due to herpes

If therapeutic intervention is not taken in time, large holes develop in the retina. Those affected can no longer see in this area. In some cases, the retina separates completely or partially from the choroid (retinal detachment).

Those affected see less well or can no longer see certain areas in their field of vision. Flashes of light and black spots often occur with a detached retina. There is a risk of complete blindness.

How can herpes on the eye be treated?

Ocular herpes is treatable. Doctors usually prescribe medication against the herpes viruses (antivirals). The aim is to alleviate the symptoms, suppress the virus more quickly and reduce the consequences of inflammation.

The exact therapy depends on the location and severity of the infection. In the event of complications and consequential damage, doctors may perform surgery.

Eye herpes medication

Doctors use so-called antivirals to treat herpes on the eye. They prevent the viruses from multiplying further. They are available as an ointment, gel and drops to be applied directly to or in the eye (local, topical). Sometimes doctors prescribe antivirals as tablets or by infusion.

The usual active ingredients are acyclovir, valaciclovir, ganciclovir and trifluorothymidine (trifluridine). The doctor selects the medication and its dosage form so that it can have the best possible effect on the inflamed area in the eye.

In some cases of ocular herpes, doctors also administer glucocorticoids (“cortisone”). They alleviate (excessive) inflammatory reactions. They reach the inside of the eye via eye drops. Doctors only use them if the corneal epithelium is intact.

In the case of superficial herpes keratitis dendritica, the doctor does not use eye drops with glucocorticoids. They stand in the way of rebuilding the epithelium. The viruses could more easily take over large areas of the epithelium and trigger so-called keratitis geographica.

The therapy usually lasts several weeks, depending on where and how severe herpes occurs on the eye. Sometimes doctors reduce the dose after a certain period of time. Those affected then continue to take the medication until the eye herpes has been completely suppressed.

Surgery for or after herpes on the eye

In some cases, corneal scars mean that those affected can no longer see clearly. Sometimes the epithelium of the cornea is so damaged that it no longer grows together completely. A corneal transplant (keratoplasty) can then help.

In so-called penetrating keratoplasty, the surgeon completely removes the damaged area of the cornea. The patient then receives a section of cornea from an organ donor.

The body’s defenses often classify transplants as foreign invaders and attack them. This happens less frequently with keratoplasty, partly because the cornea is not directly supplied with blood.

Nevertheless, rejection cannot be completely ruled out. In the event of such a reaction, herpes simplex viruses have a particularly easy time of it, as the eye is already pre-infected. Doctors therefore prescribe antivirals before and after the procedure. They also use glucocorticoids locally to suppress an immune reaction against the transplant.

Corneal infections with herpes are still possible after transplantation. However, nerves that lead into this part were severed during the operation. This gap keeps the viruses at the edge of the donated section for the time being.

If the vitreous body is cloudy and opaque as a result of acute retinal necrosis, the doctor may advise surgical removal (vitrectomy). This may also be advisable in the case of retinal detachment. You can read more about this in the text “Retinal detachment”.

Herbal remedies for herpes on the eye

The leaves of lemon balm are believed to prevent herpes simplex viruses from attaching to human cells. People with cold sores sometimes use it in the form of ointments or teas.

The body’s defenses often classify transplants as foreign invaders and attack them. This happens less frequently with keratoplasty, partly because the cornea is not directly supplied with blood.

Corneal infections with herpes are still possible after transplantation. However, nerves that lead into this part were severed during the operation. This gap keeps the viruses at the edge of the donated section for the time being.

Herbal remedies for herpes on the eye

The leaves of lemon balm are believed to prevent herpes simplex viruses from attaching to human cells. People with cold sores sometimes use it in the form of ointments or teas.

If herpes occurs when the eye is first infected, the disease usually only lasts a few days and often resolves itself. In most cases, this primary infection is not noticed at all.

Progression and prognosis of ocular herpes

Herpes recurrences are common, especially on the cornea. The symptom-free period between outbreaks varies in length. Risk factors favor a recurrence.

If the inflammation remains superficial (e.g. on the eyelid and corneal epithelium) and treatment is effective, it usually recedes without consequences. Deep herpes infections carry the risk of complications such as scars.

The longer, more severe and more often herpes occurs on the eye, the worse the prognosis. As a general rule, rapid diagnosis and treatment is important in order to avoid consequential damage. Even if there is a new outbreak.

Even with immediate treatment, the course of the disease may be protracted, as herpes can break out again and again (recurrences) and be severe.

Herpes in the eye is one of the most common causes of infectious corneal blindness worldwide. The risk of blindness is particularly high in immunocompromised patients and in cases of acute retinal necrosis caused by herpes.

Complications

Scars, vascularization and clouding of the cornea cause impaired vision or visual acuity.
Metaherpetic keratitis: Permanent corneal epithelial damage after an HSV outbreak in the eye
Glaucoma with damage to the optic nerve.
Retinal detachment in acute HSV-induced retinal necrosis (emergency!)
Superinfections: If the eye and immune system are already weakened due to the HSV infection, other pathogens (bacteria, other viruses, fungi) may join in.
Blindness

Herpes on the eye: causes and risk factors

Ocular herpes is usually caused by type 1 herpes simplex viruses. Type 2 HSV can also cause ocular herpes, especially in newborns. Herpes viruses are very contagious.

People usually become infected through direct contact with other people who are ill or through contaminated objects (e.g. towels). The infection usually goes unnoticed. Herpes only breaks out under certain conditions, for example in the eye.

Infection

The herpes simplex virus, especially HSV type 1, is widespread. People with herpes pass on the virus through bodily fluids. The fluid from herpes blisters is particularly infectious. The infection usually occurs in childhood.

You can also catch the virus from yourself. If you have cold sores, for example, you can transmit the virus from there to your own eyes. The technical term for this is autoinoculation.

There are also infected people who have no noticeable symptoms themselves but can still transmit the virus. However, they usually only excrete a few viruses.

You can find out more about infection with herpes and herpes reactivation in our main article on herpes.

Risk factors

Once infected with herpes, it often breaks out again and again. This happens particularly when the immune system is weakened or the eye is already damaged. Some risk factors favor herpes outbreaks on the eye. These include

Acute infections, fever: Other pathogens can distract the immune defense or break through protective mechanisms in the eye to such an extent that herpes viruses can penetrate more easily.
Invasive eye surgery: The eye’s natural barriers may then be more permeable to HSV (e.g. after laser eye surgery).
Diabetes mellitus: Patients whose blood sugar levels fluctuate more frequently are often susceptible to infections.
HIV and measles virus: Both viruses attack cells of the immune system and weaken it. HSV can take advantage of this situation.
Immunosuppressants, corticosteroids (“cortisone”): These drugs suppress the body’s defense reactions
Local administration of glaucoma medication
Atopy: Those affected are more susceptible to allergic reactions for hereditary reasons. HSV appears to occur more frequently in both eyes (caution: misdiagnosis possible!)
Stress: This includes physical and psychological stress.
Hormone fluctuations: Menstruation, pregnancy, medication
Contact lenses: Wearers touch their eyes more often and are therefore more likely to bring HSV into the eye. Long periods of wear and dry eyes can cause small wounds in the cornea when removing them. These are possible entry points for HSV.
Injuries in the eye, especially in the cornea, for example due to foreign bodies in the eye

Examinations and diagnosis

Ophthalmologists deal with herpes in the eye. They question the patient and examine the affected eye thoroughly. This is important as the treatment depends on the form of ocular herpes. In addition, the diagnosis is not easy, as other diseases also cause similar symptoms.

Medical history

During the medical history, the ophthalmologist will ask about the symptoms and how long they have been present. He or she will also inquire whether ocular herpes has occurred in the past or whether there are any risk factors.

Physical examination of the eye

The doctor will look for external signs such as swelling of the eyelid, redness, blisters or profuse tearing. He or she will also feel the head and neck for swollen lymph nodes.

Targeted examinations

The test with an aesthesiometer is more reliable. This is a device with “hairs” that irritate the cornea to varying degrees when touched. In this way, the doctor can find out exactly how sensitive the cornea is.

Visual acuity is checked as part of an eye test. The ophthalmologist slowly guides his fingers into the field of vision from the outside to check for possible visual defects. The patient looks straight ahead and does not move their eyes or head.

Typically, the doctor also examines the eye with a slit lamp microscope. The cornea is specially illuminated and magnified many times over. This allows the doctor to assess the different layers of the cornea. Any clouding or water retention becomes visible.

As a rule, the doctor also uses so-called fluorescein staining. To do this, he puts a solution containing the luminous dye into the eye. In the slit lamp, he then sees defects in the cornea in a greenish color.

Typical findings in ocular herpes

To diagnose ocular herpes, the doctor looks for typical findings in the slit lamp microscopy with fluorescein staining.

If HSV inflames the middle and inner corneal layer, fluid accumulates there. The doctor recognizes this as light discs (keratitis disciformis). Scars, holes, new blood vessels and thinned corneal layers are also visible in this way.

Further examinations

Depending on the findings, the ophthalmologist will then examine the back of the eye (funduscopy). Acute retinal necrosis shows bright spots on the retina, inflammatory deposits in the vitreous body and vascular changes.

This also allows the doctor to assess how far the disease has progressed. Consequential damage can also be detected with these examinations.

However, HSV can only be detected directly in the eye in the laboratory using PCR. To do this, the doctor takes a swab from the eye or obtains aqueous humor.

PCR allows the subtypes of the herpes simplex virus to be differentiated. If the treatment does not work, a change in the viral genetic material may make the pathogens resistant. The doctor will then prescribe new medication.

You can find out more about the diagnosis of herpes in general in our herpes article.

Exclusion of other causes

Preventing herpes on the eye

Herpes is highly contagious and can therefore spread easily. The virus can also be transmitted from one part of the body to the eye or vice versa. You can reduce the risk of infecting yourself or others with the following hygiene measures:

Wash your hands: Herpes viruses are not only found in bodily fluids. They can also survive for several hours on the skin, moist objects or in chilled food. Wash your hands regularly to avoid spreading the viruses.
Change towels often: If viruses remain after washing your hands, they may get onto the towel and thus to other parts of the body or people.
Disinfectants labeled “(limited) virucidal” eradicate herpes simplex viruses.
Do not scratch open herpes blisters on the eye. Otherwise the highly infectious fluid will spread more easily.
Do not touch your eyes and face unnecessarily: When inserting or removing contact lenses, HSV may get from your fingers onto the lens and into your eye (wash your hands thoroughly beforehand or wear glasses).
No make-up on the eye: If you apply make-up to the infected eye during an acute outbreak, you are likely to carry HSV into the other eye via the make-up tools used.
Wash clothes and towels hot.

Prevent further outbreaks with medication

Long-term prevention with antiviral agents (antivirals) may then be advisable in order to prevent new outbreaks of ocular herpes. Patients usually take acyclovir tablets for a year or longer. As a supportive measure, you can also try to avoid risk factors for herpes reactivation.