Keratitis
Keratitis is an inflammation of the cornea, the transparent front layer of the eye, primarily caused by the herpes simplex virus, although various other factors such as bacteria, fungi, parasites, excessive ultraviolet light exposure, vitamin A deficiency, and eye trauma can also contribute. The condition can lead to symptoms like eye redness, tearing, blurred vision, pain, light sensitivity, and a sensation of foreign matter in the eye. If left untreated, keratitis can result in corneal damage, scar tissue formation, and potential vision loss. Treatment options depend on the underlying cause and may include antiviral or antibiotic eye drops, tissue scraping, and vitamin A supplements for deficiency cases. Prompt medical attention is crucial, as early intervention often leads to effective recovery. Keratitis is notably a leading cause of corneal blindness in the United States, with thousands of related medical visits occurring each year. Awareness of its symptoms and potential complications is vital for maintaining eye health.
Keratitis
ANATOMY OR SYSTEM AFFECTED: Eyes
DEFINITION: An inflammation of the cornea caused most often by the herpes simplex virus
CAUSES: Various; may include herpes or other viruses, congenital syphilis or other bacteria, fungi, parasites, excessive ultraviolet light, vitamin A deficiency, rheumatic diseases, eye surgery or other trauma, allergic reactions
SYMPTOMS: Redness, tearing and itching, sensation of foreign matter, blurred or reduced vision, pain, discharge, light sensitivity, cloudy appearance of cornea
DURATION: Acute
TREATMENTS: Depends on cause; may include antiviral eyedrops, oral or eyedrop antibiotics, scraping away of diseased tissue, supplements for vitamin A deficiency
Causes and Symptoms
Keratitis produces an or irritation of the cornea, the outer transparent layer of the eye. It is generally caused when the has been scratched, cut, or injured so that a pathway is established for the entry of infectious agents. The resulting infection may be superficial or may involve deeper layers of the cornea. The most common cause of keratitis is the herpes simplex virus, the same virus that produces cold sores. Initially, the virus causes inflammation of the conjunctiva, the lining the eyelid. Typically, it then produces infection of the cornea with branchlike ulcerations. Less common causes of keratitis include adenoviruses, varicella zoster virus, bacteria, fungi, parasites, excessive exposure to ultraviolet light, vitamin A deficiency, rheumatic diseases, surgery on the cornea, to broad-spectrum antibiotics, to the eye that leaves scar tissue, allergic reactions to eye makeup or other irritants, and congenital (often termed keratitis). Bacterial keratitis usually results from improper cleaning or care of contact lenses.
The symptoms of keratitis typically include one or more of the following: eye redness, tearing and of the eye, a sensation that foreign matter is in the eye, blurred vision or of vision clarity, eyelids sticking together, pain, eye discharge, to light, and cloudy appearance of the cornea. If keratitis is left untreated, then corneal tissue can be destroyed, scar tissue can form, and feeling in the cornea may eventually be lost. At the first sign of eye infection, proper treatment should be administered.
Treatment and Therapy
Medical treatment of keratitis varies according to the cause. Antiviral eyedrops are administered for viral keratitis. Oral or eyedrop antibiotics are used for other infections. Some ophthalmologists prefer to scrape diseased tissue from the cornea, apply eyedrops, and cover the eye temporarily with a patch. Later, the patient may wear a special type of to prevent a reoccurrence of the infection. For cases involving dry eyes, artificial tears are prescribed for lubrication. Contact lenses may need to be replaced. In the case of vitamin A deficiency, supplements and foods rich in vitamin A (such as carrots, mangoes, spinach, squash, and liver) are prescribed.
Perspective and Prospects
According to the Centers for Disease Control and Prevention (CDC) there are around 930,000 doctor's office and outpatient clinic visits and 58,000 visits to the emergency room for keratitis or contact lens disorders each year. It is the most common cause of corneal blindness in the United States. If treatment for keratitis is started early, then it is typically very effective. In the treatment of keratitis caused by the simplex virus, it is very important not to use topical corticosteroids, as they may worsen the infection and even lead to blindness. Because herpes simplex virus remains in the body after treatment, there is a 50 percent chance that keratitis may reoccur.
Bibliography
Collier, Sarah A., et al. "Estimated Burden of Keratitis—United States, 2010." Centers for Disease Control and Prevention, 14 Nov. 2014, www.cdc.gov/mmwr/preview/mmwrhtml/mm6345a3.htm. Accessed 28 Feb. 2017.
"Keratitis." Mayo Clinic, 15 Sept. 2022, www.mayoclinic.org/diseases-conditions/keratitis/symptoms-causes/syc-20374110. Accessed 2 Apr. 2024.
"Outcomes of Amoebic, Fungal, and Bacterial Keratitis: A Retrospective Cohort Study." PLOS One, 16 Feb. 2022, doi.org/10.1371/journal.pone.0264021. Accessed 3 Aug. 2023.
Parker, James N. and Philip M. Parker. Keratitis: A Bibliography, Medical Dictionary, and Annotated Research Guide to Internet References. Icon Health, 2004.
Parker, James N., and Philip M. Parker, editors. The Official Patient’s Sourcebook on Keratitis. Icon Health, 2002.
Stapleton, Fiona. "The Epidemiology of Infectious Keratitis." The Ocular Surface, vol. 28, 2023, pp. 351-363. DOI: 10.1016/j.jtos.2021.08.007. Accessed 2 Apr. 2024.
Vorvick, Linda J. "Corneal Ulcers and Infections." MedlinePlus, US National Library of Medicine, 22 Aug. 2022, medlineplus.gov/ency/article/001032.htm. Accessed 2 Apr. 2024.
Wilhelmus, Kirk R., and Thomas J. Liesegang, editors. Interstitial Keratitis. W. B. Saunders, 1994.