Computing the influences of different Intraocular Pressures on the human eye components using computational fluid-structure interaction model

BACKGROUND: Intraocular Pressure (IOP) is defined as the pressure of aqueous in the eye. It has been reported that the normal range of IOP should be within the 10-20 mmHg with an average of 15.50 mmHg among the ophthalmologists. Keratoconus is an anti-inflammatory eye disorder that debilitated cornea unable to reserve the normal structure contrary to the IOP in the eye. Consequently, the cornea would bulge outward and invoke a conical shape following by distorted vision. In addition, it is known that any alterations in the structure and composition of the lens and cornea would exceed a change of the eye ball as well as the mechanical and optical properties of the eye. OBJECTIVE: Understanding the precise alteration of the eye components' stresses and deformations due to different IOPs could help elucidate etiology and pathogenesis to develop treatments not only for keratoconus but also for other diseases of the eye. METHODS: In this study, at three different IOPs, including 10, 20, and 30 mmHg the stresses and deformations of the human eye components were quantified using a Three-Dimensional (3D) computational Fluid-Structure Interaction (FSI) model of the human eye. RESULTS: The results revealed the highest amount of von Mises stress in the bulged region of the cornea with 245 kPa at the IOP of 30 mmHg. The lens was also showed the von Mises stress of 19.38 kPa at the IOPs of 30 mmHg. In addition, by increasing the IOP from 10 to 30 mmHg, the radius of curvature in the cornea and lens was increased accordingly. In contrast, the sclera indicated its highest stress at the IOP of 10 mmHg due to over pressure phenomenon. The variation of IOP illustrated a little influence in the amount of stress as well as the resultant displacement of the optic nerve. CONCLUSION: These results can be used for understanding the amount of stresses and deformations in the human eye components due to different IOPs as well as for clarifying significant role of IOP on the radius of curvature of the cornea and the lens.