Ooi, E.H. and Ng, E.Y.K.

where ρbl and cbl are the density and specific heat of blood, respectively, Tbl is the arterial blood temperature, which we assume to be the same as the body core temperature, bl is the blood perfusion rate inside the eye tumor, and Qm denotes the volumetric heat generated from the metabolic activity inside the eye tumor.

7.3.4. Boundary Conditions

A few assumptions have to be made prior to the specification of the boundary conditions on the surfaces of the cornea, C1, and sclera, C2. First, the presence of an eye tumor inside the human eye is assumed to have no significant effects on the heat transfer between the corneal surface and the environment. Second, blood flow inside the choroid is assumed not to be affected by the growth of a tumor inside the human eye.

Heat loss from the corneal surface to the environment via convection, radiation, and tear evaporation may be mathematically described using

where the first, second, and third terms on the right-hand side correspond to the heat loss due to convection, radiation, and tear evaporation. Respectively, hamb is the ambient convection coefficient, Tamb is ambient temperature, ε is emissivity on the corneal surface, σ is Stefan-Boltzmann constant, Evap is the amount of heat loss due to tears evaporation, and ∂T1/∂n is the rate of change of T1 in the outward unit vector, normal to the external corneal surface, C1.

On the surface of the sclera C2, heat flow from blood into the eye may be described using a single heat transfer coefficient,33 so that:

where hbl is the heat transfer coefficient between the artificial surrounding and the human eye (also known as blood convection coefficient), Tbl is the temperature of the artificial surrounding, which simulates the temperature of blood, and ∂T6/∂n is the rate of change of T6 in the outward unit vector, normal to the external scleroid surface, C2.

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