CONTAMINATION OF CONTACT LENS STORAGE SOLUTIONS

Title CONTAMINATION OF CONTACT LENS STORAGE SOLUTIONS
Author, Co-Author Michael Collins, John Coulson, Vicki Shuley, BSc (Optom), Adrian Bruce
Topic
Year
1992
Day
Sunday
Program Number
Poster 14
Room
Great Hall
Affiliation
Abstract We have investigated the contamination of storage solution bottles following two weeks of patient use. Forty-four subjects participated in the study and each used three types (Opti-free, ReNu, and AOSept) of soft lens storage solutions (cross-over study). A further 16 subjects used only one of the storage solutions over three consecutive two week periods (reliability study). Contamination of the storage solution bottles occurred in 12 of the 180 bottles sampled (ie 7%) and the level of contamination of these bottles ranged up to 10,000 colony forming units per millilitre. A wide range of microorganisms were identified in these positive samples, many of which were potentially pathogenic. For the subjects who used all 3 storage solutions in the cross-over study (n=44), a Friedman test on these data suggested that Opti-free was significantly more likely to be contaminated than either ReNu or AOSept (Chi-squared = 6.25, df = 2, p = 0.04). The results for an ANOVA on these data are less conclusive, suggesting a between treatments (product) difference, significant at p = 0.14 (F = 2.0, df = 2). There were no subjects in the overall study (n = 60) who showed contamination in more than one of the three bottles sampled. The rate of contamination of storage solution bottles was not influenced by the length of time the subjects had been wearing lenses (visit 1 to 3), by the time of year (season) at which the samples were collected, or by the subject's compliance with hand washing. Contamination of contact lens solution bottles presumably occurs through the suction of airborne microorganisms into the bottle, finger contact with the bottle tip, or leaving the bottle uncapped between uses. Advising patients to discard opened bottles of storage solution in a fixed period after opening (in line with manufacturers' instructions), irrespective of the rate of use, would seem to be prudent. Study funded by Ciba Vision Corp.
Affiliation of Co-Authors
Outline