Contact Lens Complications Resurface

After a recent lull, infections have spiked again. Here's a look at what's driving the latest outbreak.

By Samantha Stahl, Assistant Editor

In an economic downturn, there are quite a few unfortunate certainties: luxuries go by the wayside, unemployment soars and the media becomes fixated on reporting the side effects of “these troubled economic times.” One truthful headline that you might not expect to see? A major increase in corneal infections.

The influx of complications makes sense, actually. Contact lens wearers' non-compliance issues are obviously nothing new. Topping off solution, over-wearing lenses and using old cases are all practically expected behaviors at this point. These little bad habits seem to worsen, however, when patients are trying to cut costs.

“History tends to repeat itself,” says cornea specialist Terrence O'Brien, MD, of Miami's Bascom Palmer Eye Institute. He cites the increase of Acanthamoeba keratitis in the 1980s, when penny-pinching lens wearers tried to economize on solution by combining salt tablets and tap water to make homemade saline, introducing parasite contaminants from the tap water. Again, in the last few years, there was the increase in Fusarium keratitis in association with soft contact lens wear and certain multipurpose disinfection solutions.

Is the link between the economy and the increase in infections a coincidence? Dr. O'Brien doesn't think so.

“We hear so much about the popularity of refractive surgery, but there are around 35 million people still wearing contact lenses. That's a huge population potentially at risk for infectious complications,” he says. “No disinfecting product is universally effective against all classes of microbes with patient compliance always a vital consideration.”

“Half the battle is having an opportunity to properly educate,” Dr. O'Brien points out. “When people hear that there is a threat to their sight, they take it seriously.” Unfortunately, many patients don't listen to that lecture until there's already a problem.

Corneal Infiltrative Events (CIEs)

While the frequency of various complications rises and falls depending on economic tides and new product developments, there is still a standard set of issues to look for in contact lens wearers. Though CIEs typically present as irritation and eye soreness, the severity of the actual problem can vary.

Around 20% of lens wearers suffer from contact lens-induced acute red eye (CLARE) each year. When a patient sleeps in contacts, bacteria builds up on the lens and is unable to be cleared away effectively while the eye is closed, explains Dr. O'Brien.

Contact lens-induced peripheral ulcerations (CLPU), usually due to gram-positive bacteria like Staphylococcus and Streptococcus, affect 15% to 20% of lens wearers per annum. Blood vessels adjacent to the cornea are activated by chemical messengers that recruit inflammatory cells into the peripheral cornea. Again, overnight wear is a frequent trigger.

Infiltrative keratitis, though less common than CLARE and CLPU, can appear for similar reasons—overwear, lens toxicity and sensitivity to solution preservatives.

Pseudomonas ulcerative keratitis in a contact lens user.

Last but certainly not least is the uncommon but feared microbial keratitis. Estimates of affected patients range from around one in 500 to one in 2500. Dr. O'Brien reports that gram-negative organisms can occur in approximately 50% of such cases, and 20% will end up with legal blindness. About $20 million a year is spent on corneal transplants due to corneal scarring in the US alone, he says.

“With infectious keratitis, one must determine when it is necessary to culture and the type of antibiotic therapy that is most appropriate,” says cornea specialist Jesse Pelletier, MD, of Miami. “High suspicion is necessary for fungus and Acanthamoeba when irregular patient histories and presentations are uncovered, which is why culture is very important.”

He notes that smaller, peripheral infections often proceed directly to monotherapy, while sight-threatening infections must be cultured before using fortified antibiotics.

Is the Solution the Problem?

The epidemic of fungal keratitis associated with multipurpose solution use is no big secret. While solution formulas have improved, the potential for complications remains.

“Theoretically, the move to the multipurpose solutions has increased convenience,” says Dr. O'Brien. But when patients are careless with replacing solution, they lose the full benefits of fresh disinfectant biocides, not to mention that residual solution evaporating at the bottom of a case helps to create a biofilm and promotes growth of more bacteria, he explains.

“There has been a lot of discussion lately on the issue of corneal infiltrates in contact lens wear. Multipurpose solution use has a tenfold greater relative risk versus hydrogen peroxide use in developing infiltrates,” says Joseph Shovlin, OD, of Scranton, Pa. He speculates that the increased reporting of corneal infiltrates may have to do with the combination of certain solutions with silicone hydrogel lenses. “These events are most common with veteran wearers and don't seem to be related to any solution toxicity,” he says. Usually switching to a different multipurpose solution or to a hydrogen peroxide system seems to do the trick. “Fortunately, the new solution options recently released will solve many, but not all, of the common problems we encounter.”

Though solution-induced corneal staining is one of the most common complications for contact wearers, Dr. Shovlin says that corneal staining from solution preservatives does not represent a significant pathological event since the basal lamina isn't violated. The staining is “generally transient in nature, peaking at two hours for solutions preserved with PHMB and about 30 minutes with Polyquad—likely related to the uptake and quick release of preservatives on the cornea and conjunctiva.”

He reports that several investigators have shown that a hyperfluorescence seen with sodium fluorescein's affinity to PHMB makes the cornea look worse than it really is and transient corneal staining doesn't appear to increase the risk for microbial keratitis.

Can a Lens Make All the Difference?

For some patients, the contact lens itself presents the biggest problem due to allergic reactions to the lens material. Giant papillary conjunctivitis (GPC) and other allergies are some of the most common lens-related issues.

“This can be a lymphocyte-mediated immunological cycle that occurs with the combination of mechanical rubbing of lid to lens material creating chronic inflammation, mucin and protein secretion with build-up that physically manifests as a large tarsal papillae with dilated fibrovascular core,” Dr. O'Brien explains.

Fungal keratitis with microperforation and hypopyon.

A great deal of conversation surrounds the newer silicone hydrogel lenses and whether or not they live up to their claims of easing dry eye and promoting corneal health.

“Neovascularization and corneal edema have been either eliminated or greatly reduced by using lenses with a higher oxygen flux,” says Dr. Shovlin. While he explains that infiltrates may occur with any lens or solution combination, there is generally a higher rate of infiltrates with silicone hydrogels versus conventional hydrogel lenses.

“Interestingly, higher oxygen permeability in contact lenses—silicone hydrogels—has not decreased the quantity of infectious keratitis cases. This leads us to ponder the question of what other factors may be responsible. Ocular surface homeostasis alteration is still compromised even though there is better oxygen diffusion,” muses Dr. Pelletier.

He has found that keratitis, as well as other complications, are most common with extended wear lenses, followed by daily disposables and rigid gas permeable lenses. Meanwhile, Dr. Shovlin finds that stiffer lenses with a higher modulus material are more likely to cause superior epithelial arcuate lesions (SEALs) and GPC.

Daily disposable lenses seem to be an ideal solution, eliminating the issue of mucus deposit buildup that rubs against the eyelid and making maintenance easy for patients. However, even the simplest of routines come with a downside.

“We all hoped with advances in production and lower cost that disposable daily wears would be the ultimate answer, but people will try to stretch once a day to once a week or once a month,” laments Dr. O'Brien. Wearing lenses past the recommended time triggers dreaded dry eye, which can eventually lead to more serious corneal complications.

Fungal keratitis patient after management with antifungals, bandage contact lens and tissue glue.

Another unfortunate problem: Patients are increasingly turning to mail order, the internet or wholesale retailers to buy lenses—bypassing the opportunity to have a proper fitting and corneal exam with an eyecare professional. “It's like someone ordering shoes online without getting the right size or seeing if they're comfortable. But they wear them anyway and suffer the consequences with their feet,” Dr. O'Brien says.

The Compliance Issue

Contact lens advertisements have convinced wearers that they can get away with being a little too low maintenance. While asserting that a solution will take care of cleaning and disinfecting all at once, the products may ultimately reinforce lazy behaviors, some experts fear. Easy to care for products may seem great on the surface, but patients take a lot of creative license in following protocols for use.

“There's no question patients trivialize the use of contact lenses and the accoutrement needed to wear them successfully,” says Dr. Shovlin. “Many studies have shown that patients actually think they are fully compliant, but the reality is that they seldom are.” A survey conducted by the Contact Lens Council found that over 44% of lens wearers top off solution and less than 46% clean cases after each use.

He recommends reinforcing proper wear and care habits, like the need to “rub and rinse” lenses, frequent lens replacement and limiting over-wear. For patients that have significant compliance issues, disposable lenses could be a cure—but for an additional cost, which circles back to the issue of the cost-cutting connection to increasing infection.

The silver lining to the economic cycle, Dr. O'Brien says: “Any time you get these epidemics, there's one positive thing—public awareness of proper hygiene and improved care of lenses. We have had an opportunity to re-educate the public, so we now have observed fewer cases. At least until the next perfect microbial storm.” OM