What are herpes viruses?
There are some members of the herpesvirus family. The members include HSV-1 (herpes simplex virus-1) and HSV-2 (herpes simplex virus-2), HZV (herpes, zoster also known as VZV or varicella-zoster virus), CMV (cytomegalovirus), and others. HSV infection on the eyes could be caused by HSV-1.
Which form of herpesviruses can affect the eye?
HSV-1 (Herpes simplex virus-1) is the most frequent herpes virus to affect the eye. This virus is the same one that causes oral cold sores. HZV (Herpes zoster virus), which causes chickenpox in children and shingles in adults, can affect the eye as well. CMV (cytomegalovirus) causes eye infection in immunocompromised individuals, for instance, HIV-infected patients with a low count of T-cells.
What parts of the eyes are at risk of herpesviruses?
All eye parts are at risk of infection. When any eye part is affected, it’s known as herpes ophthalmicus.
The cornea is most frequently affected by HZV and HSV. Corneal infection or inflammation is called keratitis. However, these forms of viruses can also affect the uveal tissue (choroid and iris), the skin of the eyelids, as well as the retina. For this reason, an exhaustive eye exam is suggested to evaluate the degree of eye involvement.
Who is susceptible to herpes infections of the eyes?
Although a huge percentage of people (approximately 85%) carries HSV-1, not everybody who carries the virus contracts an eye infection.
When an individual carrying the virus develops immunodeficiency (for instance their immune system becomes deteriorated) due to age, HIV, medications (chemotherapy, steroids), and maybe stress, the virus will likely be triggered and incite a herpes outbreak that could entail an eye infection.
However, in numerous (if not most) instances of HSV infection, the occurrence of eye infections looks random and not essentially associated with immune weakness or episodes of stress. In fact, various research studies have indicated that the certain subtype of HSV-1 that a person bear has as much to do with the eye infections’ frequency as the person’s immune status.
What are the symptoms and signs of herpes eye infections?
The most frequent presentation for eye HZV and HSV infection is blurred vision, pain, tearing, redness, and sensitivity to light in one eye. Also, HZV is frequently accompanied by a shingles rash (small blisters or vesicles) on the temple on the side affected and occasionally the nose tip.
How are ocular herpes infections diagnosed?
Mostly, on the basis of the signs and the symptoms alone, the diagnosis can be made.
Herpes keratitis usually produces a distinctive erosion of the cornea’s outer layer. This minute erosion is known as a dendrite and presents a branching pattern that can be observed by an examiner with a blue light and an eye drop encompassing a yellow dye. Under a slit-lamp, the ophthalmologist can seek further signs to make a distinction between an HZV and an HSV keratitis. However, in either case, the first antiviral treatment is no different.
Close check-up of the other ocular tissues (including the conjunctiva, skin, anterior chamber, retina, iris, and more) also provides additional signs to make a diagnosis as well as aids to tailor treatment. In questionable instances, a culture can be acquired to fortify the diagnosis.
How are ocular herpes infections treated?
Primary treatment is with either oral or topical antiviral medication. In particularly less common instances, intravenous medication is necessary as well.
The antiviral drugs presently available block the multiplication of the virus, therefore cutting the number of viruses that are active. This may reduce the severity and duration of the infection and perhaps diminish the likelihood of a recurrence.
Unfortunately, no antiviral medication is available that cures one of the herpesviruses. The viruses are fused into the cells in the nervous system where they lie quiet and inactive for months or even years. To date, no treatment has been created that can eliminate the viruses while in their dormant state.
When the herpes virus becomes active for whatever reason, it starts replicating and its progeny pass along a nerve to the infection site (at the cornea or skin). The antiviral medications accessible now only affect these replicating viruses, but not the dormant viruses within the nervous system.
Other than antiviral medications, ointment or antibiotic drops could be utilized preventatively to diminish odds of a bacterial infection forming at the site of viral infection. This is as when the cornea has eroded, it will become at risk of a bacterial infection.
If the intraocular pressure (eye pressure) rises as a result of the eye internally swelling or trabecular meshwork infection, a pressure-lowering treatment will be necessary as well.