Herpes Simplex Keratitis

Basic Understanding

A potentially serious viral infection that can involve all parts of the eye.  Keratitis, the most common manifestation of this condition, that is infection and inflammation of the cornea, the transparent front of the eye.  Symptoms can include light sensitivity, redness, tearing, blurry vision and discomfort.  If treated promptly the condition can be treated with minimal if any long-term consequences. Initial therapy is with antiviral eyedrops.  Steroid eyedrops are often added to the regimen to quell inflammation once the virus is neutralized.  It is common, however, for this condition to linger or to be recurrent requiring long-term therapy and possibly surgical intervention.  Ultraviolet rays from the sun can provoke a flare-up making the use of Polarized eyeglasses a must.  At Palm Beach Eye Center we have the expertise to provide state of the art therapy for this potentially devastating eye condition.  In the picture seen in this article, the green branch-like green areas are the infected corneal nerve endings and are called dendrites.  

Research and Layman's Interpretation

Herpetic Eye Disease Study. A controlled trial of topical corticosteroids for herpes simplex stromal keratitis.

Ophthalmology. 1994 Dec;101(12):1883-95; discussion 1895-6.
Wilhelmus KR1, Gee L, Hauck WW, Kurinij N, Dawson CR, Jones DB, Barron BA, Kaufman HE, Sugar J, Hyndiuk RA, et al.
Purpose-To evaluate the efficacy of topical corticosteroids in treating herpes simplex stromal keratitis.
Conclusions-The time to treatment failure (defined by specific criteria as persistent or progressive stromal kerato-uveitis or an adverse event) was significantly longer in the steroid group compared with the placebo group. Compared with placebo, corticosteroid therapy reduced the risk of persistent or progressive stromal kerato-uveitis by 68%. The time from randomization to resolution of stromal keratitis and uveitis was significantly shorter in the steroid group compared with the placebo group even though both groups included patients who were removed from the study and treated with topical corticosteroids according to best medical judgment. Nineteen (33%) of the steroid-treated patients and 11 (22%) of the placebo-treated patients completed the 10 weeks of protocol therapy and had stable, non-inflamed corneas after 16 weeks. At 6 months after randomization, no clinically or statistically significant differences in visual outcome or recurrent herpetic eye disease were identified between the steroid and placebo groups.
Take home message- Steroid eyedrops decrease the corneal swelling associated with Herpes Simplex Keratitis. 

Oral acyclovir for herpes simplex virus eye disease: effect
on prevention of epithelial keratitisand stromal keratitis. Herpetic Eye Disease Study Group.

Arch Ophthalmol. 2000 Aug;118(8):1030-6.
Purpose-To investigate the effect of oral acyclovir therapy for recurrences of herpes simplex virus (HSV) epithelial keratitis and stromal keratitis and to determine if certain patients derive differential benefit.
Conclusions-Long-term suppressive oral acyclovir therapy reduces the rate of recurrent HSV epithelial keratitis and stromal keratitis. Acyclovir's benefit is greatest for patients who have experienced prior HSV stromal keratitis. Arch Ophthalmol. 2000;118:1030-1036
Take home message-Long term oral antiviral agents can decrease the recurrences of herpes simplex keratitis.

Cornea. 2001 Mar;20(2):123-8.
Predictors of recurrent herpes simplex virus keratitis. Herpetic Eye Disease Study Group.
Purpose-Determinants of the natural history of recurrent herpes simplex virus (HSV) keratitis have not been consistently established. We assessed how previous HSV eye disease affects the risk of recurrent HSV keratitis and evaluated whether demographic and other variables play any predictive role.
Conclusions-Among patients who experienced active ocular HSV disease in the previous year, a history of epithelial keratitis was not a risk factor for recurrent epithelial keratitis. In contrast, previous, especially multiple, episodes of stromal keratitis markedly increased the probability of subsequent stromal keratitis.
Take home message-Patients who experience corneal swelling from Herpes Simplex Keratitis have a higher risk of recurrent swelling.

Recurrent herpetic stromal keratitis in mice: a model for studying human HSK.

Clin Dev Immunol. 2012;2012:728480. doi: 10.1155/2012/728480. Epub 2012 Apr 23.
Stuart PM1, Keadle TL.
Take home message-This article is an example of the extensive ongoing research of Herpes Simplex Keratitis. The goal is preventing recurrence and finding a potential vaccine.

Thoughts and Experience from the Medical Director

Herpes Simplex is a condition that we regularly see at Palm Beach Eye Center.  At the time of writing this article, I saw two cases today.  Patients typically present with pain and very light sensitive eye or eyes.  Often, this is mistaken for a bacterial infection or a common viral conjunctivitis that you might see with the common cold.  Very often we will see patients started on steroid eye drops and the condition worsens.  Its a very good sign this is Herpes.  A little disclaimer here: There are many eye conditions that look just like Herpes Simplex.  Shingles also looks similar.  So does Epstein Barr Virus.  Severe dry eyes can be Herpes and when patient's aren't responding to typical dry eye treatments it should be considered.  

Any patient that is experiencing light sensitivity should be seen by an ophthalmologist, right away.  Failure to treat leads to more aggressive infection in the cornea and when its prolonged it can lead to significant scaring.  

My regimen is to immediately start patients on one or another type of antiviral. Based on severity I may use drops and oral antivirals together.  We have a few options for eye drops and several when giving patient's oral medicine.  One a patient's eye is calm that is usually my cue for starting a topical steroid drop.

Standard of care varies in terms of who will get long term oral treatment.  My current regimen at the time of writing this article is on the first episode, the antiviral is tapered and not given for a long term.  After the second episode, I continue an antiviral orally for about 6 months to a year depending on the severity of the infection and how much haze or scaring occurred in the eye.  If there is a third episode, treatment is for life.

Its important to remember there are Herpes infections resistant to one or another antiviral.  I always keep this in mind when someone isn't healing quickly.

I also find amniotic membranes to have a very important role in the healing process.  

Since Herpes infections can involve the center of the cornea (called Stroma) and the anterior chamber, conjunctiva, and retina, a thorough eye exam from a competent ophthalmologist is most important.  To learn more about what can happen in Herpes infections search for Acute Retinal Necrosis or Progressive Outer Retinal Necrosis.  See Stromal Keratitis.  See Herpes Uveitis.

Patient's with this condition are highly infectious and gloves and other contract precautions should be taken.  It can also be spread from one eye to another.  In this regard, I tell patient's to try to not to touch one eye and then the other or use the same tissue on both eyes.

At Palm Beach Eye Center, we are  always available for second opinions and primary consultations.