Role of instrument cleaning and maintenance in the development of diffuse lamellar keratitis

Abstract

Objective: To determine if instrument cleaning techniques affect the rate of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK).

Design: Retrospective case series.

Participants: Two hundred ten eyes of 109 patients.

Methods: A record review was performed of all patients who underwent LASIK at the Jules Stein Eye Institute from April 1 through June 24, 1999. During the first 6 weeks, the instruments used in LASIK surgery were cleaned according to our conventional protocol. At the end of this 6-week period, the cleaning protocol was modified and used for a subsequent 6-week period. For each eye during the two periods, the status of DLK on the first postoperative day was recorded.

Main outcome measures: Presence of DLK.

Results: During the first 6-week period, 118 eyes of 60 patients underwent LASIK surgery. In the subsequent 6 weeks, 92 eyes of 49 patients underwent LASIK surgery. The two groups included patients with similar demographic background: gender, age, and target correction. Diffuse lamellar keratitis was present in 13 of 118 eyes (11%) using our conventional protocol. In only 2 of 92 eyes (2%) did DLK develop after the protocol was modified. Using the chi-square test, the difference between the two groups was statistically significant (P = 0.01).

Conclusions: Diffuse lamellar keratitis is a fairly uncommon phenomenon after LASIK surgery. Although the cause remains to be elucidated, these results demonstrated a reduced incidence of DLK associated with alteration of cleaning procedures and a decrease in stagnant instrument cleaning fluids. The authors recommend that refractive centers avoid the use of stagnant fluids in their instrument cleaning and sterilizing protocols to minimize the occurrence of DLK outbreaks.