Using an in vitro model of lipid deposition to assess the efficiency of hydrogen peroxide solutions to remove lipid from various contact lens materials.
OBJECTIVE
To test the ability of two commercially available hydrogen peroxide disinfection solutions, one containing a surfactant and one without, to remove lipid from various contact lens materials using in vitro radiochemical experiments.


METHODS
Etafilcon A, senofilcon A and balafilcon A contact lens materials were incubated in an artificial tear solution (ATS) containing a mixture of lipids, proteins, mucin and either (14)C-cholesterol or (14)C-phosphatidylcholine for 8 h. Following incubation, the lenses were removed, rinsed, and placed for 16 h in either a surfactant-containing peroxide solution (ClearCare®), a peroxide solution devoid of a surfactant (AOSept®) or stored without solution (control). This process was repeated every day for 1 week. The lenses were extracted with a previously optimized extraction protocol, evaporated, re-suspended, fluor added and counted for their radioactive signals. Masses of lipids deposited were calculated based on standard calibration curves, the disinfection solutions were compared and repeated measures ANOVA and post hoc statistical analysis was completed using Statistica 9.


RESULTS
The results of this experiment found that daily disinfection with hydrogen peroxide solutions reduced the amount of cholesterol and phosphatidylcholine deposited on the three contact lens materials examined, however in many cases the reduction in deposition was less than 15% when compared to the control. Disinfection with the solution containing the surfactant (ClearCare), resulted in the least deposited cholesterol and phosphatidylcholine for all materials, however not all of the comparisons were statistically significant.


CONCLUSIONS
Overall, ClearCare hydrogen peroxide disinfection solution containing Pluronic 17R4 removed the most lipid from lenses when compared to the non-surfactant containing AOSept or the control, for both lipids and all lens materials. However, the differences found were quite small at times and whether these differences are clinically significant are yet to be determined.
Centre for Contact Lens Research, School of Optometry, University of Waterloo, Ontario, Canada. hmelchin@uwaterloo.ca
Holly
H
Lorentz
Miriam
M
Heynen
Helen
H
Tran
Lyndon
L
Jones
D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D018639:Contact Lens Solutions / Q000494:pharmacology*; D003263:Contact Lenses, Hydrophilic; D004203:Disinfection; D005136:Eye Proteins / Q000032:analysis*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008055:Lipids / Q000032:analysis*
D000891:Anti-Infective Agents, Local; D018639:Contact Lens Solutions; D005136:Eye Proteins; D008055:Lipids; D006861:Hydrogen Peroxide