Finite element method for fluid flow of modelling of the descemet membrane detachment and Rhemathogeneous retinal detachment

Abstract

A numerical computation of the ocular fluid mechanics incorporate with Descemet membrane detachment (DMD) and Rhemathogeneous retinal detachment (RRD) were presented. DMD and RRD are serious diseases of the human eye that might cause vision impairment and blindness.The developing mechanisms of both diseases are related to the fluid flow in the anterior chamber (AC) and vitreous cavity (VC) of the human eye. However, the measurement of the fluid data in the human eye is difficult due to the small size of the eye and extremely low velocity of the fluid flow. Therefore, mathematical models were proposed to investigate the fluid flow in the human eye with DMD and RRD respectively. The aqueous humour (AH) in the AC and the vitreous humour (VH) in the VC have similar properties to water. Thus the AH and VH were assumed as an incompressible Newtonian fluid. Navier-Stokes equations were applied to govern the fluid flow in AC and VC. In AC, the AH flow was driven by the buoyancy forces. The AH adjacent to the iris was heated and eventually rises as buoyant flow. While, the AH adjacent to the cornea becomes colder and heavier that it flows down in the direction of the gravitational force. In VC, the VH flow was induced by the movement of the eye. Finite element method was used to solve this problem. A source code (MATLAB) was constructed to run the iterative numerical procedure, to determine the approximate solutions and to display the results graphically. The results show that the circulation of the AH in the AC was affected by the types and location of the DMD. Additionally, change in the orientations (the direction of the gravitational force) and the shape (the area) of the AC do change the characteristics of the AH flow. On the other hand, the characteristic of the VH flows in the VC were dependent on the pattern and seriousness of the RRD. The VH flow in the VC were dominantly driven by the saccadic eye movement. It is observed that, the scale and location of the sclera buckling were the important factors that affect the outflow of the subretinal fluid flow into the VC.