Treating Infiltrative Keratitis in Contact Lens Wearers
BY WILLIAM L. MILLER, OD, PHD, FAAO
One of the more common entities in a busy contact lens practice is infiltrative keratitis. Although we have better contact lens materials and most patients are using disposable lenses, we still frequently encounter IK. Its predominance in contact lens wearers presents a therapeutic challenge.
Symptoms include red eyes, variable levels of pain, watery eyes and sensitivity to lights. Signs in tandem with symptoms include varying levels of conjunctival injection, slight superficial punctate staining and subepithelial infiltrates. Many symptoms occur later in the day and aren't necessarily associated with sleep.
The Clinical Picture
The incidence of IK in contact lens wearers ranges from 1.3 percent to 17.8 percent, with higher numbers reported with continuous wear. We've learned more about the dynamics and characteristics of IK over the last few years. What has developed after studies and observations from clinical practice is that there are risk factors that we should look for to prevent occurrences.
In addition, the clinical picture gives us some idea about the relative risk of IK, its ultimate severity and eventual impact on visual function (Morgan et al, 2005 and Efron et al, 2005).
Smokers and males are at a greater risk for infiltrative events. Larger IK lesions and those more central to the visual axis appear to suggest a more severe form of the disease. As a group, silicone hydrogel lenses show a lessened incidence of IK and in the event of IK, silicone hydrogel wearing patients exhibit a less severe form of the disease. Silicone hydrogel lens wearers also demonstrate a greater incidence of IK manifesting in the superior cornea.
Figure 1. Peripheral infiltrates.
IK also may mimic contact lens-associated red eye. Although similar in etiology and treatment, the clinical profile is different with CLARE typically occurring after awakening in a patient who has slept in his lenses. Unlike CLARE, the chances of a recurrence after an episode of IK aren't high; however, affected patients may succumb to other inflammatory events.
Initial treatment in contact lens wearing patients is to cease lens wear until the condition disappears. A useful additional therapy includes topical antibiotic and steroids applied every two or four hours depending on severity. They can be combination drops such as Tobradex (Alcon) to ease compliance or multiple drops using antibiotics such as tobramycin, Ciloxan (Alcon), Zymar (Allergan) and Vigamox (Alcon). My preference is Pred Forte (Allergan), but you can also use Lotemax or Alrex (both Bausch & Lomb) in mild cases. Adding this latter treatment will hasten the relief of signs and symptoms. I consider this therapy the most effective at quickly alleviating symptoms, which leads to a very satisfied patient.
It's true that most cases resolve with cessation of lens wear, but the rapid resolution of symptoms with topical therapeutic intervention outweighs the singular treatment of lens removal. CLS
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Dr. Miller is the Director, Cornea and Contact Lens Service at the University of Houston College of Optometry. He is a member of the American Optometric Association and serves on its Journal Review Board. You can reach him at firstname.lastname@example.org.