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Survey of soft lens posterior apical radius stability

12 May 1978


A survey of optometric literature indicates that soft contact lenses are not dimensionally stable but are seen to change as a function of changes in lens environment, handling and wear. Base curve, power and diameter were measured on a series of B & L soft lenses that were subjected to simulated normal use, boiling water bath sterilization, frequent dehydration and frequent freezing. Lens parameters were found to be quite stable with the exception of dehydration which tends to alter the base curves on minus lenses. Verification of the lenses in a Hydrocurve trial fitting set demonstrated a high degree of lens to lens variability which was manifested in a high fitting failure rate in our optometric clinic.


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