Contact Lens Practice Pearls
Managing Marginal Keratitis
By Gregory J. Nixon, OD, FAAO
Marginal keratitis is often defined as an infiltrative event in the corneal periphery. When these infiltrates result in an overlying epithelial defect, it technically is considered a marginal ulcer. While these inflammatory events are not limited to contact lens wear, they are common enough with lens wear for some to use the nomenclature contact lens peripheral infiltrate (CLPI) and contact lens peripheral ulcer (CLPU). Regardless of the name, these are common causes of red eyes in any busy contact lens practice.
Pathophysiology of CLPU
Histopathological analysis of CLPUs suggest that they are non-infectious and likely the result of an acute inflammatory process (Holden, 1999). Traditionally, hypoxia is thought to cause the majority of these corneal infiltrates (Thomas and Melton, 2010). However, the inflammation also occurs as a hypersensitivity reaction to high bacterial colonization and the exotoxins this produces (Dumbleton, 2002). Bacterial lens contamination is frequently associated with gram positive staphylococcal overgrowth from blepharitis, meibomian gland dysfunction, or other ocular surface disease (Dumbleton, 2002).
Additional inflammatory triggers include solution toxicity/hypersensitivity, toxicity from entrapped post-lens tear debris, and, rarely, microbial invasion of compromised corneal epithelium. The result is often a contaminated lens surface that triggers localized conjunctival injection, corneal edema, and peripheral infiltrates characteristic of a typical CLPU presentation. However, in each case you must rule out infectious microbial keratitis (MK) resulting from bacterial binding and invasion from gram negative bacteria such as Pseudomonas (Willcox and Holden, 2001).
Guiding Your Treatment
The initial treatment plan for most cases of marginal keratitis is temporary cessation of lens wear and pharmaceutical intervention to reduce symptoms and aid corneal recovery. When concern about MK is high (lesion >1mm, marked epithelial defect, significant pain, presence of anterior chamber cells), it is prudent to treat the case as infectious MK (Dumbleton, 2002). Appropriate treatment for suspected MK would be a broad spectrum topical antibiotic, such as a fourthgeneration fluoroquinolone (Thomas and Melton, 2010). However, because most CLPU cases represent sterile inflammation, the use of an antibioticsteroid combination drop can immediately address the inflammatory response within the cornea while providing prophylaxis against bacterial invasion of the compromised ocular surface (Thomas and Melton, 2010). Additionally, the antibiotic component can help reduce bacterial overgrowth that may have provoked a hypersensitivity inflammatory response.
After resolution, further clinical decision-making is required prior to resuming lens wear. The guidelines I reviewed in my April 2010 Contact Lens Practice Pearls column for refitting patients who have CLARE are appropriate for CLPU/marginal keratitis patients as well. Make sure that patients discard their contaminated lenses and start with new lenses and a new case. Additionally, instruct patients to improve their lid hygiene and contact lens care compliance. Review all steps of proper lens disinfection, including rubbing lenses and using fresh disinfecting solution each night, as well as proper case care. Lenses should be replaced according to their appropriate schedule, and cases should be replaced every three months.
These guidelines can resolve marginal keratitis expeditiously and return patients to healthy lens wear with reduced risk of recurrent keratitis. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #179.
Dr. Nixon is an associate professor of clinical optometry and the extern coordinator at The Ohio University College of Optometry. He is also in a group private practice in Westerville, Ohio. He is on the Allergan Academic Advisory Board and the B+L Advisory Board. You can reach him at firstname.lastname@example.org.