Herpes can infect the eye and is called Herpes Simplex Keratitis. It most often involves only one eye and affects the cornea. It can cause pain, redness of the eye, tearing, light sensitivity, and a feeling like there is grit in the eye. Unlike herpes elsewhere, topical antiviral therapy is the treatment that is most effective when an outbreak occurs. It is noteworthy that viral shedding occurs in tears even when patients have no symptoms and that treatment with Valacyclovir decreases the number of recurrences just like it does for infections elsewhere.
It is extremely important to differentiate herpes simplex keratitis usually caused by HSV-1 (and rarely by HSV-2) from Herpes Zoster Ophthalmicus, which is caused by the Varicella Zoster Virus (VZV) - the same virus that causes chickenpox and shingles. Herpes Zoster Ophthalmicus requires prompt evaluation by an ophthalmologist as it can affect deeper parts of the eye and is treated differently than herpes simplex keratitis. This is why it’s important for all patients with eye involvement to be evaluated by a physician in-person.