contact lens case reports
Corneal Infiltrates in Contact Lens Patients
BY PATRICK J. CAROLINE, FAAO, & MARK P. ANDR�, FAAOW
While the pathophysiology of corneal infiltrates is not completely understood, we do know that infiltrates are the result of a cascade of corneal defense responses. A host of ocular conditions are associated with the appearance of corneal infiltrates, including: ocular trauma (mechanical toxic or hypoxic); ocular surface disease; ocular allergy; a wide range of systemic diseases and reactions; numerous chronic and acute inflammatory conditions; and of course, infectious keratitis.
FIG. 1: Patient E.K
With such an array of diverse etiologies, it is often difficult to identify the exact cause of corneal infiltrates in the contact lens wearing population.
FIG. 2: Patient S.W.
This case history reviews three patients who presented with small midperipheral and peripheral corneal infiltrates. All three patients were long-term soft contact lens wearers and were compliant with their individual lens replacement schedules.
E.K. wore daily disposable contact lenses, while S.W. and R.N. wore three-month planned replacement contact lenses with a one-step lens care regimen.
It is well-known that corneal infiltrates occur much more often in soft lens wearers than in rigid lens wearers.
This may be related to the larger size and translimbal fit of soft lenses, or may be due to other factors, such as the absorptive nature of the polymers, peripheral hypoxia or retrolens debris.
Distinguishing noninfectious sterile corneal infiltrates from infectious microbial keratitis is often difficult. However, sterile infiltrates are usually hallmarked by lesions less than 0.5mm in diameter; minimal pain or anterior chamber reaction; minimal conjunctival injection; the absence of discharge; and epithelial staining, limited to a superficial keratitis.
The three patients mentioned were discontinued from contact lens wear and treated with appropriate antibiotics or antibiotic/steroids for two weeks.
In each case, the corneal infiltrates resolved in 10 days or less with no loss of visual acuity. All patients have returned to soft contact lens wear and have experienced no recurrence.
Figure 3: Patient R.N
Historically, preserved lens care regimens have been implicated as one of the major causes responsible for peripheral corneal infiltrates.
While this may be true in a few isolated situations, preservative toxicity should be considered as only one of the many factors responsible for sterile peripheral infiltrates
Patrick Caroline is an associate professor of optometry at Pacific University and an assistant professor of ophthalmology at the Oregon Health Sciences University.
Mark Andr� is director of contact lens services at the Oregon Health Sciences University.