STUDIES OF THE POST-LENS TEAR FILM

Noel Brennan

Abstract

PURPOSE. Inadequate tear exchange behind a contact lens may lead to accumulation of cellular debris and bacteria. Failure of the clearance mechanism may thus be responsible for adverse events and corneal inflammatory reactions. Despite the importance of this feature in contact lens wear, techniques for assessing the post-lens tear film have been poorly developed and utilized. In this study we compare a functional measure with a structural index of the post-lens tear film. METHOD. Ocular signs, lens fit, and patient symptoms were recorded for fifteen subjects before and after wearing Acuvue 2 contact lenses in three separate wearing trials. For each trial, a different storage solution (Allergan Complete ComfortPlus, Alcon OptiFree Express, Bausch & Lomb ReNu Multipurpose Solution) was used for presoaking of lenses. Post-lens tear film was graded by observing the specular reflection with a slit-lamp biomicroscope 15 minutes after lens insertion. On separate occasions, the post-lens tear exchange was tracked by instilling a 2µL drop of 0.1% FITC dextran on the back surface of a contact lens prior to insertion and monitoring the elimination of this marker by fluorophotometry from 5 to 30 minutes following lens insertion.

RESULTS. The combined data showed a statistically significant association between post-lens tear film grading and elimination of FITC dextran (F=5.1, p=0.05), whereby a patterned post-lens tear film was associated with reduced clearance of the marker. Individually, two of the solutions tested showed weakly significant associations between fluorescence decay and post-lens tear film grading. The clinical assessment of lens fit, signs and symptoms were associated with significant effects on post-lens tear film measures in only isolated cases.

CONCLUSIONS. We interpret the correlation between post-lens tear film gradings and fluorescence measures as signifying that thinner post-lens tear films are associated with a lower post-lens tear exchange. Clinical assessment of the post-lens tear film may thus be a valid method for evaluating the flow of tears beneath a contact lens.

Details

Year: 2001

Program Number: Poster 22

Author Affiliation: Brennan Consultants

Co-Authors: Andrew Jaworski, Vicki Shuley, Chantal Coles, Peter Simmons, Jerry Paugh

Co-Author Affiliation: Brennan Consultants, Brennan Consultants, Brennan Consultants, Allergan Consumer Eye Care

Room: Exhibit Hall C