Abstract
Purpose: :
To understand the propensity of various soft contact lenses for deposition of common tear film lipids.
Methods: :
Ten unworn etafilcon A, galyfilcon A, senofilcon A, and lotrafilcon A lenses were individually soaked in 1.0 mL of 1.75 µg/mL cholesterol oleate or 1.0 mL of 0.5 µg/mL phosphatidylcholine solution for 8 hours and 14 days. Each lens was then removed from the incubation solution, and the deposited lipids were extracted with a 1:1 chloroform-methanol extraction. Individual lipid extracts underwent cholesterol oleate and inorganic phosphate assay quantification for each lens extract from each time point (all values for both lipid types in µg/lens).
Results: :
For cholesterol oleate, etafilcon A had significantly more at 8 hours than at 14 days but lotrafilcon A had significantly more at 14 days than 8 hours (both p = 0.005). Galyfilcon A and senofilcon A had no difference between the two time points (p = 0.80 and 0.57, respectively). There was no difference in the four materials after 8 hours (range = 3.95 to 4.80). At 14 days, the highest to lowest levels were as follows (p senofilcon A (4.98) = galyfilcon A (4.39) > etafilcon A (2.75). For phosphatidylcholine, senofilcon A had more deposited after 14 days compared to 8 hours (p = 0.02). There were no time point differences for the other materials. At 8 hours, the highest to lowest levels were as follows (p galyfilcon A (1.99) > etafilcon A (1.15) > senofilcon A (0.78). At 14 days, the highest to lowest levels was as follows: lotrafilcon A (4.12) > galyfilcon A (1.47) = etafilcon A (1.83) = senofilcon A (1.14).
Conclusions: :
In general, hydrogel and silicone hydrogel contact lenses appear to saturate relatively quickly with these lipids (i.e., within the first 8 hours). While there were material differences in deposition, lotrafilcon A appears to deposit these lipids the most whereas etafilcon A deposits these lipids the least.
Keywords: lipids • cornea: tears/tear film/dry eye • cornea: basic science