Herpes simplex virus (HSV) is the germ that causes cold sores. Most people contract facial HSV as young children; the virus typically enters the body through the mouth. The initial HSV infection often goes unnoticed because it frequently causes no symptoms. After the infection, the virus remains dormant (hibernating) in the facial nerves; it may reactivate at any time causing a recurrent infection. The mouth and eyes share common nerves; therefore, recurrent HSV may present as an eye infection. The National Eye Institute estimates nearly 50,000 HSV eye infections are diagnosed annually in the United States.
Pain
HSV eye infections--also known as ocular herpes--are painful. Eye pain is a particularly difficult form of pain for most people to tolerate. This may be a good thing with regard to ocular herpes because it causes a person to seek medical care early, which helps limit potential complications.
Tearing
The HSV infected eye generally tears copiously. The fluid is the typical consistency of tears--watery and clear. It does not resemble pus. Notably, ocular HSV usually involves only one eye, not both.
Eye Redness
The HSV infected eye is typically red and irritated. The lining of the eyelids (the conjunctiva) and the rims of the eyelids where the eyelashes are attached are particularly red and inflamed. One or more herpetic blisters may be present on the eyelids. The area around the blisters is characteristically red due to inflammation as the body fights the virus.
Scratchy Sensation in the Eye
People with ocular herpes have the sensation of something being in the eye. This sensation is persistent, aggravating and terribly uncomfortable. As the eye heals, this symptom slowly wanes.
Light Sensitivity
Ocular herpes causes an intense aversion to light because it precipitates eye pain. This symptom is known as photophobia. It persists until the infection clears, which typically takes 2 to 3 weeks.
Eye Swelling
Herpetic blisters on the eyelids cause local swelling. Blisters can also occur on the corneal surface--the surface of the eyeball. The affected area of the cornea swells causing blurred vision.
Visual Disturbances
Ocular herpes can infect the deep layers of the cornea--the clear area at the front of the eyeball. This leads to ulcers in the cornea, which are small cavitary sores. These sores characteristically blur vision and may cause permanent visual problems if corneal scars form. Rarely, HSV can infect the deeper structures of the eye including the iris (the colored part of the eye) and the retina (the nerve tissue at the back of the eye). Infection in these structures may cause permanent visual problems and possibly blindness. Early diagnosis and treatment of ocular herpes decreases the risk for these serious complications.
References
- Digital Journal of Ophthalmology: Herpes Simplex Virus in the Eye
- University of Maryland Medical Center: Corneal Ulcers and Infections, Symptoms
- Merck Manual: Herpes Simplex Keratitis
- University of Illinois at Chicago, Department of Ophthalmology and Visual Sciences:Ocular Herpes Simplex
- Patient UK: Herpes Simplex Eye Infections
