Dynamic viscoelastic properties of bovine vitreous

Rheological properties of the vitreous and the role of hyaluronic acid

“…Because the tissue clearly loses fluid during the course of the rheology experiment, we believe that the initial moduli are closest to the in vivo moduli. The steady-state moduli we have measured provide a lower bound that is significantly higher than any estimates found in the literature (Bettelheim and Wang, 1976;Lee et al, 1994a;Tokita et al, 1984;Zimmerman, 1980), by up to an order of magnitude (Tokita et al, 1984).…”

“…While it appears that our steady-state moduli are systematically lower than in vivo, they are also useful for several reasons. First, while they represent minimum values for the native moduli, they are higher than any previous estimates found in the literature (Bettelheim and Wang, 1976;Lee et al, 1994a;Tokita et al, 1984;Zimmerman, 1980). Second, they provide useful target values for those striving to create synthetic vitreous replacements (Chirila et al, 1998;Dalton et al, 1995;Soman and Banerjee, 2003).…”

“…The lubricating ability of its constituent molecules and its fragile network structure have (Bettelheim and Wang, 1976;Pfeiffer, 1963;Tokita et al, 1984), magnetic microrheology (Lee et al, 1992(Lee et al, , 1994a, in vivo visual tracking for humans (Zimmerman, 1980), and more recently, acoustic techniques (Walton et al, 2002). These techniques allow for comparative analyses in terms of phenomenological parameters, but not for quantitative measurements.…”

A finite element infant eye model to investigate retinal forces in shaken baby syndrome

“…However, Weber and Landwehr consider the vitreous body as part of the system, and as such, state that the material is more rubber-elastic. The non-invasive material determination technique results in stiffer vitreous material properties that are a closer match, to what is described [16,18] to be an infant vitreous, than the other compliant viscoelastic materials [17,56,57].…”

The rheological behaviour of animal vitreus and its comparison with vitreal substitutes

“…The gel structure is formed by an ordered network of fine collagen fibrils (diameter of about 10 nm) immersed in a viscoelastic matrix composed mainly of highly hydrated HA macromolecules [-1, 2]. This structure permits the vitreus body to be a transparent medium, to maintain ocular shape, to serve as a mechanical absorber of any movements and impacts for bordering tissues [3] ~nd, finally, to help the retina to remain in position. The vitreus body, however, may lose its structural or functional properties because of various diseases.…”