Early detection of ocular infections crucial in preventing long-term complications

Corneal scarring, vision loss, anterior uveitis and cranial neuralgia are some of the more severe complications that may arise when ocular infections go untreated.

Viral infections are a widespread occurrence, caused by many organisms and often first contracted during childhood. While generally treatable, ocular involvement must be addressed early to avoid vision loss and other severe complications.

A corneal infection occurs when a virus enters the eye, causing painful inflammation and watery discharge. If untreated, infection may lead to impaired vision due to ulceration of the cornea. In extreme cases, scarring and subsequent blindness may occur, necessitating a corneal transplant.

Most commonly, viral corneal infections are caused by herpes simplex virus 1 (HSV-1), herpes zoster virus (HZV) or adenovirus, the cause of the common cold.

Like most viruses, these target people who are immunosuppressed. For those patients with latent disease, flare-ups are often linked to stress.

HSV-1

HSV-1 is contracted by a majority of children and is known to be a leading infectious cause of corneal blindness in the United States. While HSV-1 may be contracted by the neonate passing through the mother’s birth canal, most newborns are contaminated by contact with an unsanitized hand, Marguerite B. McDonald, MD, FACS, OSN Refractive Surgery Board Member, told Ocular Surgery News.

Initial systemic exposure generally results in subclinical symptoms that go unnoticed, whereas reactivation of the virus leading to corneal involvement manifests as a dendritic, geographic or marginal ulcer on the cornea with accompanying pain, vision loss and redness, Edward J. Holland, MD, OSN Cornea/External Disease Board Member, said.

When first contracted, more problematic strains of HSV-1 may cause follicular conjunctivitis, which can be associated with palpebral vesicles, corneal micro-dendrites and preauricular adenopathies, Dr. McDonald said.

After initial infection, HSV-1 typically goes dormant in the trigeminal ganglion and/or cornea and is reactivated by various physiological, emotional or environmental stressors, such as hormonal changes or excessive sun exposure, Dr. McDonald said. Contact lens use may trigger recurrence in patients with a history of HSV keratitis, Dr. Holland said.

“The initial recurrences present as epithelial disease, but the subsequent recurrences can progress toward deeper layers, resulting in stromal keratitis or anterior uveitis,” Dr. McDonald said. “The risk of blindness increases with the number and severity of recurrences, [so] prompt treatment is critical.”

Zirgan (ganciclovir ophthalmic gel 0.15%, Bausch + Lomb) is a topical antiviral recently approved for the treatment of HSV dendritic keratitis. The safety and efficacy of ganciclovir is a great improvement over trifluridine, according to Dr. Holland.

“[Ganciclovir ophthalmic gel] is viral-specific and avoids the extreme toxicity of the previous nonspecific topical antivirals,” he said. “This new antiviral is the first topical medication introduced in the U.S. for the management of HSV in 30 years. We have been waiting a long time for a new, more effective therapy.”

Dr. McDonald said she also recommends ganciclovir as an improvement over prior topical antiviral treatments. Its efficacy has prompted some to prescribe it without concomitant oral therapy, she said.

HSV-1 can also be treated with oral antiviral therapy. According to Dr. McDonald, oral antiviral treatments include Zovirax (acyclovir, GlaxoSmithKline), Valtrex (valacyclovir, GlaxoSmithKline) or Famvir (famciclovir, Novartis).

Dr. Holland said he recommends oral antiviral prophylaxis for monocular patients with a history of HSV-1 infection, those with multiple recurrences within a year, patients on topical steroids for HSV immune stromal keratitis and anyone who underwent corneal transplant due to HSV-1-induced scarring.

HZV

HZV is often contracted during childhood in the form of chicken pox, reappearing in older patients as shingles. It causes painful skin blisters and possible ocular complications, which are usually signaled by a lesion on the nose known as Hutchinson’s sign.

“Unless the patient is immune-compromised, once [he or she] has an episode of shingles, you do not usually see another episode,” Dr. Holland said.

“The usual presentation of HZV is vesicles along a trigeminal dermatome, then ocular involvement of the cornea and/or intraocular inflammation days to weeks, and sometimes even months, after the original skin eruption,” he said.

Patients with shingles tend to have elevated corneal lesions, and their swollen eyelids may prevent them from blinking properly, causing secondary dry eye and exposure keratitis, Dr. McDonald said.

In severe cases, blisters become infected with Staphylococcus aureus, or the virus impairs ocular and/or cranial nerves, resulting in post-herpetic neuralgia.

Dr. McDonald and Dr. Holland said they recommend the HZV vaccine for patients 60 years or older as a preventive measure. For recurrent HZV outbreaks, they advised an oral antiviral regimen.

Topical capsaicin cream, over-the-counter analgesics, prescribed medications such as Neurontin (gabapentin, Pfizer) and tricyclic antidepressants are used to treat symptomatic pain, according to Dr. McDonald. – by Michelle Pagnani

• Edward J. Holland, MD, can be reached at C/O HolPro Vision Ltd., 10794 Saunders Lane, Union, KY 41091; email: eholland@holprovision.com.
• Marguerite B. McDonald, MD, FACS, can be reached at Ophthalmic Consultants of Long Island, 360 Merrick Rd., 3rd Floor, Lynbrook, NY 11563; email: margueritemcdmd@aol.com.
• Disclosures: Drs. Holland and McDonald are consultants for Bausch + Lomb.