The viscoelastic properties of the vitreous humor measured using an optically trapped local probe

Fiona Watts, Lay Ean Tan, Manlio Tassieri, Niall McAlinden, Clive Wilson, John Girkin, Amanda Wright

Research output: Contribution to conferenceProceeding

3 Citations (Scopus)


We present results demonstrating for the first time that an optically trapped bead can be used as a local probe to measure the variation in the viscoelastic properties of the vitreous humor of a rabbit eye. The Brownian motion of the optically trapped bead was monitored on a fast CCD camera on the millisecond timescale. Analysis of the bead trajectory provides local information about the viscoelastic properties of the medium surrounding the particle. Previous, bulk, methods for measuring the viscoelastic properties of the vitreous destroy the sample and allow only a single averaged measurement to be taken per eye. Whereas, with our approach, we were able to observe local behaviour typical of non-Newtonian and gel-like materials, along with the homogenous and in-homogeneous nature of different regions of the dissected vitreous humor. The motivation behind these measurements is to gain a better understanding of the structure of the vitreous humor in order to design effective drug delivery techniques. In particular, we are interested in methods for delivering drug to the retina of the eye in order to treat sight threatening diseases such as age related macular degeneration.
Original languageEnglish
Publication statusPublished - 2011
EventSPIE Optics and Photonics - San Diego, United States
Duration: 21 Aug 201125 Aug 2011


ConferenceSPIE Optics and Photonics
CountryUnited States
CitySan Diego


  • viscoelastic properties
  • vitreous humor
  • optics

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