Corneal and scleral thickness and anterior chamber dimensions are required for understanding developmental and pathological processes. Parameters of the eyeball are also required to calculate optical and material properties. As the eyeball resembles a pressure vessel, it has been suggested that elasticity of the cornea and sclera could be calculated from the measurements of thickness. Baseline corneal and scleral thicknesses and anterior chamber dimensions and how these change with incremental increases of intraocular fluid are measured in fresh porcine eyes using the Visante OCT (optical coherence tomography). At baseline, corneal thickness is almost constant. Anterior scleral thickness is variable, decreasing from 0.91±0.07 mm near the limbus to a minimum of 0.58±0.13. Posterior scleral thickness is more constant with an average of 0.78±0.09 mm. Near the optic nerve the thickness increases to 1.00±0.09 mm. Average baseline anterior chamber angle, diameter, and depth were found to be 33.15±4.91 deg, 13.60±0.38 mm, and 2.13±0.22 mm, respectively. After fluid injections, maximum changes in corneal and scleral thicknesses were 9 to 10 and 1 to 3%, respectively. Anterior chamber angle and depth decreased slightly but significantly. Changes in the eyeball coats with fluid injections, indicate that the pressure vessel model can be applied to the eye to calculate corneal and scleral elasticities.
The presented paper reports the continuation of research on the linear model of human eyeball. We use the physically linear eye model, also presented in the paper by Srodka et al.'), but we introduce a new element to this model- passive non-accommodating eye lens. We look for such conditions, that placed upon geometry and material parameters of the eyeball, would enable the model to show optical self-adjustment effect. The Finite Element Method was used to model the eyeball tissue by means of physically linear materials. The current paper also investigates limitations imposed on boundary conditions, as well as geometrical and material parameters of model, by postulated requirement of eyeball models the optical self-adjustment effect. Subsequently, the results of investigations carried out on the model with and without eye lens are compared.