Contact lens material characteristics associated with hydrogel lens dehydration

  • Ramamoorthy P
  • Sinnott L
  • Nichols J
  • 29


    Mendeley users who have this article in their library.
  • 15


    Citations of this article.


PURPOSE: To determine the association between material dehydration and hydrogel contact lens material characteristics, including water content and ionicity.

METHODS: Water content and refractive index data were derived from automated refractometry measurements of worn hydrogel contact lenses of 318 participants in the Contact Lens and Dry Eye Study (CLADES). Dehydration was determined in two ways; as the difference between nominal and measured (1) water content and (2) refractive index. Multiple regression models were used to examine the relation between dehydration and material characteristics, controlling for tear osmolality.

RESULTS: The overall measured and nominal water content values were 52.58 +/- 7.49% and 56.88 +/- 7.81% respectively, while the measured and nominal refractive indices were 1.429 +/- 0.015 and 1.410 +/- 0.017. High water content and ionic hydrogel lens materials were associated with greater dehydration (p < 0.0001 for both) than low water content and non-ionic materials. When dehydration was assessed as the difference in refractive index, only high water content was associated with dehydration (p < 0.0001).

CONCLUSIONS: High water content and ionic characteristics of hydrogel lens materials are associated with hydrogel lens dehydration, with the former being more strongly associated. Such dehydration changes could in turn lead to important clinical ramifications such as reduced oxygen transmissibility, greater lens adherence and reduced tear exchange.

Author-supplied keywords

  • Contact lenses
  • Dehydration
  • Tear osmolality

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Padmapriya Ramamoorthy

  • Loraine T. Sinnott

  • Jason J. Nichols

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free