Blog

How Herpes Simplex Affects the Eye

Author: Premier Eye Associates
We’ve all heard of herpes. Many associate it as a sexually transmitted disease, whereas others may think of cold sores or painful blisters. What we do not commonly think about is how if affects the eye—which is actually quite common!

 

What Is Herpes Simplex?

Herpes Simplex is a DNA virus. There are two types—type 1 and type 2.

Herpes Simplex Type 1 is considered to be an “above the belt” infection, meaning it is not a sexually transmitted disease. It may present with cold sores or fever blisters around mucous membranes, most commonly around the lips.

However, not everyone who has herpes simplex type 1 will be symptomatic. Since it is a virus, it can lie dormant within the nervous system. Some individuals may never be symptomatic, whereas other individuals may experience signs or symptoms when undergoing extreme stress, while traveling, or when sick.

Herpes Simplex Type 2 is a sexually transmitted disease. It is characterized by painful blisters in the genital region.

Regardless of type—1 or 2—Herpes Simplex is highly contagious. In fact, over 50% of the population in the United States has some form of Herpes Simplex!

 

Brief Anatomy Review of the Cornea

To best understand the different ways herpes infections can present in the eye, it is best to understand the different layers of the eye that herpes can infect.

Herpes simplex infections primarily involve the outermost layer of the eye called the cornea.

The cornea is the clear structure that you can touch with your finger. It is heavily concentrated with nerves.

The cornea is made up of 5 layers, from outermost (anterior) to interior (posterior): Epithelium, Bowman’s Membrane, Stroma, Descemet’s Membrane, and the Endothelium.

The epithelium is the outermost structure. It helps to protect the eye from debris.

The stroma is the thickest, middlemost layer. It is the “meat and potatoes” of the cornea.

The endothelium is the most fragile layer of the cornea. It is very thin, once its cells are damaged and die they cannot regenerate. Nonetheless, it also plays one of the most important jobs—it is responsible for pumping water out of the cornea to ensure it does not swell and cause blurred vision.

 

Herpes and the Eye

As stated above, herpes tends to hide within the nervous system. The eyes are a part of the central nervous system.

This means that, when activated, the eyes can become involved and actively infected. There are several different presentations of herpes simplex ocular infections. Below are some of the more common presentations:

Blepharoconjunctivitis

Blepharoconjunctivitis is a herpes simplex infection involving only the eyelid margins. It presents with itchy, painful, vesicles on the eyelids.

It is important, if you suspect you may have blepharoconjunctivitis, to see your eye doctor as soon as possible to initiate treatment, as these vesicles can rupture and spill into the cornea resulting in a concurrent corneal infection, which is quite painful and can affect your vision.

 

Dendritic Keratitis

Dendritic Keratitis is the stereotypical presentation herpes simplex ocular infection. It occurs when the virus invades the epithelium of the cornea leading to the appearance of a dendritic ulcer.

A dendritic ulcer is an epithelial defect that follows the involved axonal pathway. They tend to look almost snake like with little finger-like projections at the edges.

Not all forms of ocular herpes simplex involve the cornea, therefore not all ocular herpes simplex infections will have dendrites.

As stated in the introductory section, herpes simplex is a virus that resides within the nervous system. One of the most commonly affected nerves is the trigeminal nerve—or cranial nerve 5. The trigeminal nerve has 3 major branches—the ophthalmic (V1), mandibular (V2), and maxillary (V3).

The ophthalmic branch of the trigeminal nerve extends into, and innervates, the cornea. Hence why we can see dendrites on the cornea in dendritic keratitis.

The severity of dendritic keratitis can range from mild irritation to possible decreased vision, depending on where the dendrite is located and how large it is.

Dendritic keratitis is often self-resolving, however seeing your eye doctor and taking a special anti-viral eye drop helps to relive symptoms and prevent scarring (and more permanent vision disturbances) from occurring.

 

Disciform Keratitis

Disciform keratitis is a bit more serious of a complication of herpes simplex infections as it is more likely to scar and cause permanent visual disturbances than the previous ocular involvements.

Disciform keratitis is inflammation within the endothelium or stroma of the cornea. It can occur concurrently with a dendritic keratitis flare-up, or on its own.

When the endothelium becomes inflamed, it cannot function effectively which can result in an excess cumulation of water within the corneal stroma. This can cause blurry, painful vision and is termed “corneal edema”.

We want to get corneal edema under control as quickly as possible, as excess water swelling in the stroma can increase pressure and compress the endothelium, resulting in further endothelium damage leading to more corneal edema in a never-ending cycle.

Along with endothelium damage and corneal edema, disciform keratitis presents with stromal haze and inflammation. This appears as white fluffy discs of inflammation (called precipitates) that are often found underneath focal areas of edema.

The precipitates can interfere with vision ranging from minor blur to significant vision loss. This inflammation needs to be controlled and precipitates treated before significant scarring or neovascularization (new blood vessel growth) of the stroma occurs.

If neovascularization and scarring occurs, any vision loss associated with it will likely be permanent.

The tricky thing with treating and preventing disciform keratitis is that the normal treatment for herpes simplex is anti-viral eyedrops. Typically, we want to stay away from steroid eye drops as it can give the virus easier routes to replicate and further invade the cornea.

However, to reduce inflammation, as in inflammatory precipitates, steroids are the preferred method of treatment. In order to combat this, your eye doctor will need to prescribe a careful balance of anti-viral eyedrops in addition to a low-dose steroid drop. It will be important to have regular follow-ups to watch for worsening of the condition and adjustments to treatment may be necessary.

If you or someone you know has been diagnosed with herpes simplex type 1 or 2, it is important to see your eye doctor yearly to monitor for changes and to have medications available to help limit flair-ups and control any active infection. Regardless of type, if you have a history of either condition be sure to tell your eye doctor so he or she can watch for early signs of changes and best treat any active flair ups.

 

Dr. Anthony Spina and the staff of Premier Eye Associates specialize in glasses, soft contact lenses, hard contact lenses, and medical eye exams. Call our eye doctor in Auburn, AL today at (334) 539-5391 or schedule an appointment online  if you are interested in learning more about herpes simplex affects on the eye.  Our optometrist provides only the highest quality eye care services amongst eye doctors in the Auburn Alabama area.

Proud Members


Auburn-Opelika’s Best Eye Doctor by the OA News Reader’s Choice