THE EFFECT OF SUCCESSFUL CONTACT-LENS WEAR ON MUCOSAL IMMUNITY OF THEEYE

Objective: This study aimed to assess the effect of contact lens wear on the mucosal defenses of the outer eye against infection. Design: A case-controlled study of daily contact lens wearers in their initial 6 months of contact lens wear. Participants: Contact lens wearers (mean age, 23.1 years; 47 subjects) were compared with age-matched control subjects (mean age, 24.7 years; 44 subjects). Intervention: Outer eye defenses were studied by assay of tear constituents and quantitative c onjunctival microbiology. Main Outcome Measures: Antimicrobial activit y of tears was studied by assay of total immunoglobulin A (IgA), IgA i sotype-specific antibodies reactive with Escherichia coli, Haemophilus influenzae, Staphylococcus epidermidis, albumin and lysozyme, and the ocular surface microbial load determined using quantitative microbiol ogy of the conjunctival sac. Results: The IgA isotype-specific antibod ies reactive with E. coli (P = 0.03) and S. epidermidis (P = 0.068) we re lower in contact lens wearers, but antibody:albumin ratios were not significantly different in the two groups, Contact lens wear also had no significant effect on tear IgA, albumin, or lysozyme or its ratios with albumin. Bacterial numbers and colonization rates for coagulase- negative staphylococci were greater in contact lens wearers than in ag e-matched control subjects, Corynebacterium sp. and non-Enterobacteria ceae (P = 0.007) were isolated more frequently and in greater numbers from contact lens wearers. Colonization rates were increased for Coryn ebacterium sp., but non-Enterobacteriaceae were transient. In both dai ly contact lens wearers and age-matched control subjects, most conjunc tival flora were transient rather than colonizing, and no subject deve loped an outer eye infection during the study. Conclusion: These resul ts suggest that daily contact lens wear does not significantly alter t he mucosal defenses of the outer eye that function to eliminate organi sms from the conjunctival sac and prevent outer eye infection.