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Updated: Aug 9, 2026

Development of an In Vitro Ocular Platform to Test Contact Lenses
Published on: April 6, 2016
Flexibility of hard gas permeable contact lenses
1Department of Ophthalmic Optics, Glasgow College of Technology, Scotland.
Abstract:
Gas permeable (GP) lenses can flex on some eyes producing unpredictable clinical results. A method of measuring the flexibility of hard GP materials has been developed and shown to be repeatable. Materials in the form of flats rather than lenses were used. Differences between materials were found and in general a linear relation was shown to exist between maximum flexing and quoted oxygen permeability (r = 0.78, p less than 0.05). It is recommended that flexibility be measured and reported in the data presented with all new GP polymers. The term "hard" rather than "rigid" in describing GP lenses is suggested.
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