April 2011
Volume 52, Issue 14
ARVO Annual Meeting Abstract  |   April 2011
Mesh Size of Soft-Contact-Lens Hydrogels
Author Affiliations & Notes
  • Csaba Kotsmar
    Dept. of Chemical and Biomolecular Eng., University of California at Berkeley, Berkeley, California
  • Teresa Nadolski
    Dept. of Chemical and Biomolecular Eng., University of California at Berkeley, Berkeley, California
  • Clayton J. Radke
    Chemical Engineering, Univ of California, Berkeley, Berkeley, California
  • Footnotes
    Commercial Relationships  Csaba Kotsmar, Alcon (F); Teresa Nadolski, Alcon (F); Clayton J. Radke, Alcon (F)
  • Footnotes
    Support  Alcon Grant
Investigative Ophthalmology & Visual Science April 2011, Vol.52, 6489. doi:
  • Views
  • Share
  • Tools
    • Alerts
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Csaba Kotsmar, Teresa Nadolski, Clayton J. Radke; Mesh Size of Soft-Contact-Lens Hydrogels. Invest. Ophthalmol. Vis. Sci. 2011;52(14):6489.

      Download citation file:

      © ARVO (1962-2015); The Authors (2016-present)

  • Supplements

Transport of solute molecules through soft-contact-lens (SCL) hydrogels, such as salts, wetting agents, nutrients, and drugs is important to on-eye behavior. Solute molecules larger than the sieve or mesh size, however, can not penetrate the gel. This work measure the mesh size of contact lens materials and demonstrate that solute diffusion coefficients increase with increasing mesh size.


To determine the mesh size of HEMA-based hydrogels with various crosslink densities, we utilize oscillatory shear rheometry. The zero-frequency storage modulus of the lens material is inversely proportional to the square root of the mesh size. We synthesize hydrogels from HEMA and MAA with varying crosslink densities and measure the storage modulus for MAA contents varying between 0 and 100 %. We use two-photon confocal microscopy to measure solute diffusion coefficients in the hydrogels. Transient concentration profiles are fit to classical theory to give the solute diffusion coefficients (D).


For crosslink densities ranging from 0.1 to 1% in 30% MAA/70% HEMA, the mesh size decreases linearly from 9±1.3 to 2±0.5 nm. A typical fluorescein-dextran (4000 g/mol) concentration profile is shown in Figure 1. D increases from 2.1±0.1 x 10-8 cm2/s to 8.3 ± 0.1 x 10-7 as the mesh size increases from 2 to 9 nm.


Using shear rheometry and polymer physics we successfully measure mesh sizes of SCL materials. As mesh size increases, solute diffusion rates increase, all else being equal. Mesh size now becomes a tool for designing contact lens materials for specific applications.  

Keywords: contact lens 

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.