Osmolality and buffering agents in soft contact lens packaging solutions

Aim: The study determined the effects of packaging solution osmolality and buffering agent on soft contact lens parameters. Methods: One lens type from each FDA contact lens material category was equilibrated to phosphate buffered saline (PBS) or borate buffered saline (BBS), at three osmolality con...

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Bibliographic Details
Published in:Contact lens & anterior eye 2004-03, Vol.27 (1), p.21-26
Main Authors: Lum, Edward, Perera, Indrani, Ho, Arthur
Format: Article
Language:English
Subjects:
Buffering agent
Contact lens
Osmolality
Osmolarity
Packaging solutions
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Summary:Aim: The study determined the effects of packaging solution osmolality and buffering agent on soft contact lens parameters. Methods: One lens type from each FDA contact lens material category was equilibrated to phosphate buffered saline (PBS) or borate buffered saline (BBS), at three osmolality concentrations: 270, 310 and 414 mOsmol/kg. Lens diameter (LD), base curve (BOZR) and back vertex power (BVP) were measured and compared to nominal packaging label values. Results: Statistically significant differences were found in all three parameters across all osmolality levels for both buffering agents. Etafilcon A showed the largest amount of parameter change, followed by alphafilcon A and balafilcon A. Lotrafilcon A was the least affected. LD of alphafilcon A lenses (greater than ±0.2 mm) and BVP of lotrafilcon A and etafilcon A lenses (greater than ±0.25 D) measured outside the International Standards Organization (ISO) tolerance from their packaging labels when measured in solutions that mimicked their packaging solutions. Conclusion: Osmolality and buffering agents influence lens parameters. Packaging solutions can vary the parameters of some lens types from their nominal value to outside the tolerance range set by ISO.
ISSN:1367-0484
1476-5411
DOI:10.1016/j.clae.2003.11.002