Diagnosis: Herpes simplex virus keratitis
The patient was sent to the ophthalmology clinic, where a slit-lamp examination of the right eye showed 3+ injection, large dendritic epithelial defects spanning the majority of the cornea (with 10% haze), and trace nuclear sclerosis of the lens. These findings were consistent with a diagnosis of herpes simplex virus (HSV) keratitis, with a likely neurotrophic component (decreased sensation of the affected eye compared with that of the other eye). There was no evidence of secondary infection.
Discussion
The global incidence of HSV keratitis is approximately 1.5 million, including 40,000 new cases of monocular visual impairment or blindness each year.1 Primary infection with HSV-1 occurs following direct contact with infected mucosa or skin surfaces and inoculation. (Our patient likely transferred the infection by touching her eyes after touching her nose or mouth.) The virus remains in sensory ganglia for the lifetime of the host. Most ocular disease is thought to represent recurrent HSV (rather than a primary ocular infection).2 It has been proposed that HSV-1 latency may also occur in the cornea.
The symptoms of HSV keratitis include eye pain, redness, blurred vision, tearing, discharge, and sensitivity to light.
The 4 diagnostic categories
There are 4 categories of HSV keratitis, based on the location of the infection: epithelial, stromal, endotheliitis, and neurotrophic keratopathy.
Epithelial. The most common form, epithelial HSV manifests as dendritic or geographic lesions of the cornea.3 Geographic lesions occur when a dendrite widens and assumes an amoeboid shape.
Continue to: Stromal