Density of ocular components of the bovine eye.

PURPOSE

Density is essential for acoustic characterization of tissues and provides a basic input for ultrasound backscatter and absorption models. Despite the existence of extensive compilations of acoustic properties, neither unified data on ocular density nor comparisons of the densities between all ocular components can be found. This study was undertaken to determine the mass density of all the ocular components of the bovine eye.

METHODS

Liquid components were measured through mass/volume ratio, whereas solid tissues were measured with two different densitometry techniques based on Archimedes Principle. The first method determines the density by measuring dry and wet weight of the tissues. The second method consists of immersing the tissues in sucrose solutions of varying densities and observing their buoyancy.

RESULTS

Although the mean densities for all tissues were found to be within 0.02 g/cm by both methods, only the sucrose solution method offered a consistent relative order for all measured ocular components, as well as a considerably smaller standard deviation (a maximum standard deviation of 0.004 g/cm for cornea). The lens was found to be the densest component, followed by the sclera, cornea, choroid, retina, aqueous, and vitreous humors.

CONCLUSIONS

The consistent results of the sucrose solution tests suggest that the ocular mass density is a physical property that is more dependent on the compositional and structural characteristics of the tissue and than on population variability.