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Corneal ulcers and infections require early diagnosis and intensive topical treatment
Causes and symptoms vary; cycloplegic agent is often overlooked as adjunct therapy for bacterial keratitis.
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The major culprit causing a corneal ulcer is an infection associated with bacteria, viruses, fungi or parasites, according to the National Institutes of Health, and treatment should be prompt, comprehensive, and aggressive to prevent scarring of the cornea.
“Important variables in this paradigm are the type and virulence of the organism, corneal infection location, patient immune status and the use of an appropriate antimicrobial agent,” OSN Cornea/External Disease Board Member Thomas John, MD, said.
“Corneal infection accounts for about 30,000 cases annually in the United States,” said John, who considers the infection an ocular emergency. “While bacteria, fungi, Acanthamoeba and herpes simplex infections are to be considered among causative organisms, in some cases multiple organisms can be involved.”
Evaluation
Symptoms include blurry or hazy vision, an eye that appears red/bloodshot, itching and discharge, photophobia, extremely painful and watery eyes, and a white patch on the cornea, according to the NIH.
“History of contact lens wear, pain out of proportion to ocular findings, past history of herpes ocular infection, corneal injury with plant material, recent history of ocular surgery, and systemic diseases — especially those affecting the immune system — are important considerations in the diagnosis and treatment of keratitis and corneal ulceration,” John said.
Patching the eye of a contact lens wearer with a corneal abrasion is dissuaded, due to the increased risk for bacterial keratitis, according to the Preferred Practice Pattern (PPP) of the American Academy of Ophthalmology. The PPP also states that the use of a cycloplegic agent is often overlooked as adjunctive treatment, but is indicated when substantial anterior chamber inflammation is present. The agent may decrease pain and synechia formation. Corticosteroids should also be considered after 48 hours for a known causative infection.
For corneal infections in general, biomicroscopic evaluation includes “the location of the infection (namely, central region involving the visual axis vs. a peripheral cornea), depth of corneal infection, secondary thinning, proximity to the limbus/sclera, anterior chamber inflammation and anterior vitreous cells, especially in suspected cases of postoperative endophthalmitis,” John said.
Testing encompasses corneal scraping for smear and culture. In selected cases, though, corneal biopsy may be required, according to John.
Therapy
For therapy, frequent topical broad-spectrum antibiotic drops around the clock should be instituted, along with a cycloplegic agent to prevent synechiae and offer comfort. When confronted with methicillin-resistant Staphylococcus aureus, “topical vancomycin drops would be drug of choice,” John said.
“Close follow-up is essential in the overall management of corneal infection,” he said.
Corticosteroid eye drops to control inflammation and decrease residual scar “may be considered, when the type of organism has been identified and possibly eliminated,” John said. But there must be no threat of corneal melt or descemetocele. Similarly, organisms such as Nocardia, fungus, herpes simplex and Acanthamoeba must be excluded.
“Potential complications include corneal perforation, corneal scar, intraocular extension with endophthalmitis, scleritis secondary to scleral extension, loss of vision and loss of eye,” John said.
Severe ulcers may require a corneal transplant, according to the NIH.
“When medical treatment fails, with continued expansion of ulceration, corneal melt and potential impending perforation, a therapeutic keratoplasty is often required to save the globe,” John said. “The tissue should be sent for both culture and histopathologic evaluation to determine the offending organism.”
Although corneal infections can potentially cause significant damage to the cornea, “early diagnosis and comprehensive, aggressive treatment can result in an optimal outcome, and a happy patient,” John said. – by Bob Kronemyer
- References:
- National Institutes of Health. MedlinePlus. Corneal ulcers and infections. www.nlm.nih.gov/medlineplus/ency/article/001032.htm.
- American Academy of Ophthalmology. Bacterial Keratitis Preferred Practice Pattern (PPP). www.aao.org/preferred-practice-pattern/bacterial-keratitis-ppp--2013.
- For more information:
- Thomas John, MD, is a clinical associate professor at Loyola University at Chicago, and in private practice in Oak Brook, Tinley Park and Oak Lawn, Ill. He can be reached at tjcornea@gmail.com.
Disclosure: John reports no relevant financial disclosures.