ABSTRACT
PURPOSE: To assess the visual performance of Acuvue bifocal contact lenses at different illumination levels using a stereoscopic parameter, the maximum disparity. We compare the results with those for progressive spectacle lenses. METHODS: We used a modified Wheatstone stereoscope and random-dot stereograms (RDS) as tests. The maximum disparity was measured for each observer at different luminance levels. RESULTS: Maximum disparities did not show statistically significant differences for a wide range of luminance levels with contact lenses. The maximum disparities found when some contact-lens users wore progressive spectacle lenses were similar. CONCLUSIONS: The results show that the Acuvue bifocal lenses offer good performance for a near visual task, in this case the maximum disparity, for changes in illumination and are similar to that with progressive spectacle lenses.
Subject(s)
Contact Lenses , Depth Perception , Lighting , Photic Stimulation/methods , Adult , Distance Perception , Equipment Design , Eyeglasses , Humans , Middle Aged , Optics and PhotonicsABSTRACT
The antimicrobial efficiency of 20 commercially available solutions for soaking and rinsing soft contact lenses was studied in relation to 5 bacteria (Escherichia coli, Staphylococcus epidermidis, Pseudomonas aeruginosa, Bacillus subtilis, and Serratia marcescens) and 1 fungus (Candida albicans). Each product was separately inoculated with each of six microorganisms, and samples of the inoculated contact lens solutions were taken at predetermined times, placed in a recovery medium, and incubated. Where there was growth, the colonies were counted. There were differences in performance even between solutions labeled as having the same antimicrobial content. One of the solutions marketed in Spain to soak hydrogel contact lenses failed to inactivate all six test strains.
Subject(s)
Bacteria/drug effects , Bacterial Adhesion/drug effects , Candida albicans/drug effects , Contact Lens Solutions/pharmacology , Contact Lenses, Hydrophilic/microbiology , Drug Compounding , Polyhydroxyethyl Methacrylate , Bacteria/growth & development , Candida albicans/growth & development , Colony Count, Microbial , Humans , Microbial Sensitivity Tests , SpainABSTRACT
Bacterial contamination of hydrophilic contact lens solutions may play an important role in contact lens-associated ocular infections. This study investigated bacterial contamination in 52 different hydrophilic contact lens solutions marketed in Spain by 12 different companies. We filtered the entire contents of 5 new, factory-sealed bottles from each of the 52 brands and cultured the fitter on a neutralizing broth plate. Bacteria were cultured, isolated, and identified from 29 of the 260 bottles tested (11.15%). Eight of the 52 brands had at least 1 of the 5 bottles contaminated (15.38%). Contaminated solutions originated from four different companies. One manufacturer contributed most of the positive cases due, presumably, to an industrial contamination by Pseudomonas fluorescens. The rest of the culture-positive bottles were contaminated by Bacillus spp. and Oerskovia spp.
