Evaluation of Contact Lenses by Microbial Enumeration and Protein Determination

Contact lenses worn for varying periods of time (from 1 to 48 months) were subjected to microbiological examination by plate counts and protein determination. Seventy percent of the lenses displayed bacterial colony counts below 120 colony‐forming units (CFU)/lens, 28 percent were in the range of 140 to 9060 CFU/lens, and one lens was contaminated with >6 × 10 4 CFU/lens. Fungal contaminants were detected in three lens specimens in the range of 220 to 760 CFU/lens. Protein accumulation showed wide variation of up to 1.2 mg of protein per lens. Statistical analysis indicated highly significant associations (p < 0.001) between the bacterial colony counts obtained with three different media. Some significant associations were found between the protein concentration and bacterial counts. The data did not indicate statistically significant relations between the above variables and either the water content or the length of wear of the contact lenses.