TIME-DEPENDENT STRESS AND DISPLACEMENT OF THE EYE WALL TISSUE OF THE HUMAN EYE

Myopia or short sightedness, is the most important predisposing factor to retinal detachment(1,2). The relative risk of detachment rises wit h increasing myopia(3). The model characterizes that because the sever ity of myopia increases with tile axial length (antero-posterior diame ter) of the eyeball, the relative risk of retinal detachment rises wit h increasing eye size. We present a mathematical model of the time-dep endent shear stress force that occurs in the thin eye wall shell suppo rting the vitreous humour inside the Eye globe during the acceleration and deceleration phases of saccadic eye movement. Results show that t he shear force Increases as the thickness of the eye wall decreases. I t Is common for myopes to have thinner eye wall tissue than emmetropes . In addition, if account is taken of the increased force required to provide normal saccadic movement of myopic (larger) eyes, then the she ar force is up to seven times greater than that experimental for emmet ropes. (C) 1997 Elsevier Science Ltd for IPEM.