Herpesviruses, adenoviruses, picornaviruses, and Molluscum contagiosum may infect the eyes. M. contagiosum infects the eyelids, causing inflammation (blepharitis) and small raised bumps on the skin of the eyelids. Infections with M. contagiosum are self-limiting and will clear without treatment, though it is highly infectious through direct contact. Adenoviruses and picornaviruses may cause conjunctivitis, often as a side effect of an upper respiratory infection. These infections will commonly resolve without treatment over the course of one to two weeks.
Herpes simplex virus 1 or 2 (HSV-1 or HSV-2) can affect almost any ocular tissue, including the optic nerve, retina, trabecular meshwork, iris, cornea, conjunctiva, and eyelid. However, HSV-1 is the most common cause of ocular infections. HSV-1 primarily affects the face and is the cause of cold sores on the mouth. The virus is spread to the eye from touching an open sore and then rubbing the eyes. Involvement of the eyelid and periocular skin has the typical appearance of a cluster of blisters that eventually scab over and resolve. Though the condition is self-limited, people are treated with antiviral agents to shorten the course of the disease and reduce the chances of corneal exposure to the virus. People who contract HSV-1 of the cornea will experience a gritty, foreign-body sensation in the eye, mild eye redness, and tearing. The classic sign of infection is seen on slit-lamp examination by an ophthalmologist. The HSV forms a dendritic ulcer. A dendritic ulcer is an ulcer (hole in the stomach lining) that has the appearance of a dendrite like the branching network of a tree on the epithelial surface. Although the infection can resolve on its own, prompt treatment is necessary to prevent corneal scarring from the ulcer. This is given in the form of oral and/or topical antiviral agents such as acyclovir/valacyclovir and trifluridine along with a topical steroid to reduce scarring. The steroid should never be given without concurrent antiviral treatment, as doing so can make the infection worse.