When it came to his contact lenses, Akshay Patel, 21, admits his hygiene was not the best.
“Sometimes I showered in them, and once in a while I slept in them,” the Rutgers pharmacology student said. “I didn’t always change the contact lens solution, I didn’t always take the time to clean them, and I probably had the same contact lens case that I started with in college.”
Though Patel’s story is not unusual, the possible result of his poor habits is: a case of Acanthamoeba keratitis, a rare infection of the cornea that can cause permanent visual impairment or blindness.
Patel’s infection was diagnosed by Amir Azari, a cornea surgeon at Philadelphia’s Wills Eye Hospital, who said the hospital gets about 15 to 20 such cases per year.
Acanthamoeba is a microscopic organism found worldwide in soil and water – even water that is treated. Most people are exposed to it but few are sickened by it.
The infection often is associated with wearing contact lenses, swimming with lenses in swimming pools or fresh water, sitting in hot tubs, using homemade sodium chloride solutions to clean lenses, and cleaning lenses infrequently. Sleeping with contact lenses can cause small tears on the surface of the eye through which the infection can enter.
In the United States, an estimated 85 percent of cases occur in contact lens users, according to the Centers for Disease Control and Prevention. It’s rare, with about 33 cases per million contact lens wearers, but serious. About one-quarter of the people with the infection require cornea transplants.
Acanthamoeba made headlines in 2007, when a moisture-locking contact lens solution made by Advanced Medical Optics was linked to the infection. The product subsequently was recalled.
Early diagnosis is crucial, said Stephen Orlin, director of cornea service at the Scheie Eye Institute of the University of Pennsylvania Health System. “Early on, it is easier to treat,” he said. “Later on, you can lose an eye as the condition worsens.”
The condition often is difficult to detect and treat. Symptoms may include mild or severe pain, redness, blurred vision, sensitivity to light, the sensation of having something in the eye, and excessive watering, according to Azari.
“Basically, this is an infection that can go undiagnosed for many months because it looks like many other things, including infections with certain viruses, such as herpes, or nonspecific sickness on the surface of the eye,” Azari said. “Often these are treated with topical steroids, which can make the Acanthamoeba worse.”
Both hard and soft contact wearers are at risk from the parasite, Azari said. Wearers of Ortho K lenses, used at night to reshape the cornea to improve sight, can have an increased risk of contracting Acanthamoeba, in addition to other fungal infections.
Half of the diagnoses can be made clinically by looking for early signs that the amoeba has infiltrated the outer tissue of the cornea. Doctors look for signs like roughness of the cornea, followed by inflammation of corneal nerves. Later stages will show a haziness or white ring around the cornea, which implies an advanced stage of the disease, Orlin said.
If there is a clinical suspicion of the condition, a scraping of the eye is sent to pathology. Acanthamoeba exists in two forms: trophozoites and cysts. Trophozoites form double-walled cysts that are incredibly resistant to eradication.
Patient histories are also vital.
“If we know that a patient has been sleeping or swimming in contact lenses, we can diagnose with great confidence,” Azari said.
Treatment can take months.
“Even knowing the diagnosis, it can take many months of treatment before it heals,” Azari said. “In some cases, the infection can create a hole in the cornea and patients can require a corneal transplant.”
Orlin also noted the cysts can reactivate, making it extremely important to continue treatment until the infection is completely cleared.
With his contact lenses causing him discomfort in October, Patel visited several doctors who unsuccessfully treated his condition as a fungal or bacterial infection. Unable to find a solution, he went to Azari, who diagnosed Acanthamoeba.
“I went home and looked it up online,” Patel said. “I was pretty scared; it looked pretty grim.”
To treat Patel’s infection, Azari relied on two antimicrobial agents: propamidine isetionate (brolene) and polyhexamethylene biguanide (PHMD). Patel administered the eyedrops every hour around the clock for two weeks, gradually decreasing the medications as his eyes began to show improvement.
During this time, his left eye was watering so much he went through “two to three tissue boxes a day.” With the affected eye extremely sensitive to light, he spent most of his time in the dark. Eventually, he ended up wearing a patch over his left eye for six months.
“I couldn’t keep my eyes open,” he said. “When I took a shower, I realized that my vision was pretty bad.”
It took three months to rid his eye of the infection, and he was left with a scar on his eye. For a month and a half, Patel had his eyelid stitched shut to allow moisture behind the lid to help lubricate, protect, and heal the scar.
“This is one of those things that you say, ‘It won’t happen to me.’ But it can. Just because I wouldn’t take two to three minutes to clean my contacts and change the solution, or 30 seconds to take them out to take a shower.
“You really have to go to the eye doctor if you have irritated eyes,” he said. “It was a big reality check.”
“Both consumers and medical professionals need to be aware of this so it can be diagnosed earlier,” Orlin said. “People can lose their eyesight.”