Abstract
Purpose:
This study compared the cleaning efficacy of Rigid Gas Permeable (RGP) lens care systems.
Methods:
The care systems tested included two single bottle multipurpose products; Boston Simplus and Unique pH, a two bottle system; Boston Advance Cleaner and Conditioning Solution and a 3 bottle system; Lobob Optimum. Efficacy testing was completed using Boston IV (itafocon B) RGP lenses. Ten lenses were deposited in vitro for each product evaluation. The deposition solution contained a combination of lipids and proteins. The lipids included cholesterol and a palmitic acid ester while the proteins consisted of lysozyme, lactoferrin, mucin, and albumin. These were intended to simulate lens exposure to the tear film. Squalene was also added to the mixture to mimic the oils from lens handling often seen as “finger prints” on RGP lens surfaces. One deposition cycle consisted of exposure to the simulated tear solution followed by drying. After the completion of 10 deposition cycles, the level of deposition was determined by computer enhanced image analysis. An image of each lens was converted to mean grey scale, which is a numerical representation of the degree of deposition. This value was used as the baseline for calculation for each individual lens. Each lens was re-imaged after a single cleaning regimen and the % deposition removal was calculated.
Results:
The image analysis demonstrated that three of the care systems, Simplus, Advance, and Optimum removed significantly greater amounts of lipid/protein deposits (p-value<0.05) than Unique pH. The mean % removal was 95% (Simplus), 91% (Advance), and 95% (Optimum) compared to 83% (Unique pH).
Conclusions:
RGP lens care products demonstrated varying degrees of effectiveness to clean lipid and protein deposits. The Boston Advance system, Lobob Optimum, and Boston Simplus provided the best overall cleaning performance. Unique pH was not as effective in lipid or protein removal. Deposit removal may have implications for contact lens wearing comfort and vision.
Keywords: 477 contact lens