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.
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