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Influence of environmental factors in the in vitro dehydration of hydrogel and silicone hydrogel contact lenses
Author(s) -
MartínMontañez Vicente,
LópezMiguel Alberto,
Arroyo Cristina,
Mateo María E.,
GonzálezMéijome José M.,
Calonge Margarita,
GonzálezGarcía María J.
Publication year - 2014
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.33057
Subject(s) - dehydration , cls upper limits , materials science , relative humidity , gravimetric analysis , silicone hydrogel , environmental chamber , biomedical engineering , nuclear chemistry , chemistry , contact lens , medicine , biochemistry , organic chemistry , ophthalmology , meteorology , physics
Purpose: To analyze in vitro the influence of different environmental conditions on the dehydration pattern of seven currently marketed hydrogel (Hy) and silicone hydrogel (Si‐Hy) contact lenses (CL). Methods: Three Hy and four Si‐Hy CLs were evaluated. CLs were exposed to four different relative humidity (RH) conditions (5%, 30%, 50%, and 70%) and two air flow (AF) rates (0 and 2.75 m/seg) within an environmental chamber. Dehydration was assessed using the gravimetric method. Data were taken at baseline, 5, 10, 15, 20, 30, 45, 60, 90, and 120 minutes of exposure. Dehydration rate (DR), valid dehydration (VD) and stabilization time were calculated. Results: The interaction between RH, AF and the type of the CL material had a significant effect ( p ≤ 0.03) on DR up to 60 minutes. The maximum differences in VD values among CL occurred around 15 minutes exposure varying from 25.16% to 42.75%. Stabilization time was quicker under the 5%RH with AF condition than under 70% RH without AF one for most CLs. Conclusions: Lower RH seems to increase CL dehydration being further accelerated with the AF presence. The dehydration pattern is material dependent, thus current marketed CLs behave differently under several controlled environmental conditions. Future in vivo studies should confirm these outcomes. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 764–771, 2014.