infection
Reexamining Contact Lens Infections
This year's Fusarium outbreak has prompted optometry to reevaluate the care of these patients.
JIM THIMONS, O.D., F.A.A.O.

It's not often that established clinical care patterns change, especially those underwritten by evidenced-based medicine. Unfortunately, the recent Fusarium keratitis outbreak has created a need for practitioners to reassess our practice patterns regarding management of our contact lens patients in general and the treatment of microbial keratitis in these patients specifically.

1. The patient's right cornea under slit lamp shows an active epithelial defect with marginal necrosis.

Historical management

Over the last decade, clinicians have used a very successful algorithm for managing routine microbial keratitis in contact lens patients. It involved the use of monotherapy with a fluoroquin-olone (initially third, now fourth generation) at an initial accelerated dose rate (q1h to q2h). This was followed by a taper and the addition of a topical steroid once the organism had been effectively subdued and significant inflammation was present. This system was underwritten by excellent clinical studies and had been proven in tens of thousands of therapeutic interventions. Then March 2006 came.

Seemingly over-night the entire ophthalmic world was put on notice that it would need to derive a new method for treating microbial keratitis in contact lens patients, and institute new protocols regarding the identification and management of what was a fairly straight-forward clinical entity.

Case report

The following case is a typical example of how the Fusarium epidemic has changed the clinical protocols in our office and how clinicians in general should rethink the care of patients with microbial keratitis. A 34-year-old caucasian female presented initially with a complaint of pain and redness O.D. over the preceding 24 to 36 hours. The symptoms had slowly increased and also included light sensitivity and a foreign body sensation along with decreased vision.

Ocular history was positive for a prior infection approximately two years ago that was treated uneventfully. The patient admitted to occasional overnight contact lens wear, but not recently. Medical history, family ocular history and medications were non-contributory. The patient said she was unsure of her contact lens solution brand.

Clinical findings

2. After several days of treatment, the keratitis and symptoms began to improve.

Clinical examination revealed the patient was in mild to moderate distress with a noticeable injection of the right eye accom- panied by mild lid edema.

Visual acuity was 20/50 O.D. and 20/20 O.S. Pupils were asymmetric but equally reactive though slightly miotic O.D. Slit lamp exam revealed a 4- to 5mm lesion on the right cornea with an active epithelial defect, marginal necrosis and a 1+ anterior chamber reaction (see photo 1). The left eye was unremarkable other than mild giant papillary conjunctivitis. Prior to the current concerns regarding Fusarium, typically, we would have started this patient on a course of fourth generation fluoroquinolone therapy, as described above, and followed-up within 24 hours. In this case, I chose to implement a new protocol that my colleagues and I created to address the Fusarium outbreak. Since differentiating organisms such as Fusarium on initial clinical examination from more pedestrian microbes, such as Staphylococcus Aureus, is not possible, it's essential to first identify the source of the infection, then implement therapy, and monitor for signs of progression or improvement.

Three aspects of treatment have changed when dealing with a contact lens-related microbial keratitis; fluoroquinolone selection, anti-inflammatory management and use of cultures.

Treatment options

While treating with a fourth generation fluoroquinolone is still the initial standard of treatment, a subtle difference between the molecules lends an advantage in this instance to Zymar (gatifloxacin, Allergan) in the form of Benzalkonium chloride (BAK). Historically, BAK has been the most effective preservative available in eye care. It also has independent antifungal properties, giving you an initial interventional advantage, while waiting to determine if the patient has an active fungal keratitis either via the lab or observation.

The second aspect of this case that differs from traditional protocols is the use of cultures to aid in the identification of a causa-tive organism given the patient's contact lens history and the lack of definitive information on the type of solution she used. While bacterial cultures (Blood, Chocolate and Sabouraud's agars) can show growth between 24 and 48 hours, microbes, such as fungi, nocardia and mycobacterium frequently require extended periods to demonstrate positive identification (one to four weeks). For this reason, you must perform vital staining with agents such as Gomori Methenamine Silver, which has good cellular identification of Fusarium and can provide rapid feedback.

The third area of management that has changed is the use of steroids to control inflammation in microbial keratitis. As previously stated, in this current environment, it's inappropriate to initiate steroid therapy in the absence of laboratory verification or visible clinical improvement on standard therapy with epithelial wound healing as a definitive endpoint. This said, you have an option that is both safe and effective for inflammation management at the initial presentation and that is the use of cyclospor-ine A (Restasis, Allergan). While the drug was approved to treat dry eye, we now understand that dry eye is an inflammatory-initiated disease, for which cyclo-sporine has excellent anti- inflammatory efficacy.

It also has several interesting off-label applications. One study found it reduced the number of meibomian gland inclusions in patients with meibomian gland dysfunction.¹ Additionally, cyclosporine does not promote growth of fungal organisms unlike steroids. The dose rate is variable, but in this case I used cyclosporine at q3h, which is about one vial per day and implemented Homatropine 5% bid.

3. Final resolution occurred at 10 days.

Resolution

I followed the patient the next day, though she had little improvement. On day three, however, the cornea showed a significant decrease in the epithelial defect and the presence of healthy epithelium at the wound margin (see photo 2). Anterior chamber reaction was decreased, and the patient reported better comfort. Vision was minimally improved. The laboratory results reported minimal growth of Staphylococcus Aureus and no evidence of hyphae or spores on the scrape, which would have indicated a need for antifungal therapy (amphotericin B or natamycin q30 min. and oral fluconazole b.i.d.) immediately. We monitored the patient on the above regimen and her keratitis signs and symptoms improved over the course of several days. The final resolution occurred 10 days out, at which point we discontinued her medications and advised the patient to return to contact lens wear in another ten days.

This case is an excellent example of the new paradigm in management of microbial keratitis. Due to the difficulty of identifying Fusarium in its early manifestations, be vigilant against the possibility of fungal disease, and alter clinical therapy to address that risk. Using the tools available and the medical laboratory, you can safely and effectively treat these patients while the epidemiologic and pathophysiologic reasons for the current epidemic are delineated.

1. Perry HD, Doshi-Carnevale S, Donnenfeld ED, et al. Efficacy of commercially available topical cyclosporine A 0.05% in the treatment of meibomian gland dysfunction. Cornea. 2006 Feb;25 (2):171-5.