Abstract
Abstract: :
Purpose: Myopia has been shown to have an incidence of up to 25% in the western world. Retinal detachments occur in more than 11% of pathologic myopes. Here, we evaluate the role of biomechanical factors in the development of retinal tears and detachments. The biomechanical factors are: (1) retinal surface area, (2) vitreous volume, (3) retinal wall tension, and (4) retinal velocity in saccadic eye movement. Methods: A series of mathematical models of hyperopic, emmetropic, and myopic eyes with axial lengths ranging from 21–33 mm are developed. The retinal surface area, vitreous volume, retinal wall tension, and linear velocity of the retina in a saccadic eye movement are calculated and compared. Results: As compared to emmetropic eyes, hypertropic eyes have a 13% decrease in retinal surface area, 35 % decrease in vitreous volume, and 14% decrease in wall tension and velocity in saccadic eye movement. Compared to emmetropic eyes, severely myopic eyes have a 100% increase in retinal surface area, 180% increase in vitreous volume, 41% increase in wall tension, and 100% increase in retinal velocity in saccadic eye movement. Conclusions: Biomechanical factors related to globe size influences the development of retinal tears and detachments in myopia. An increase in retinal surface area increases the statistical risk of retinal tears. An increase in wall tension increases intraretinal stress and the likelihood of tear propagation. Increases in retinal velocity result in high peak stresses during saccadic eye movements. Large globe size increases the biomechanical risk factors for retinal tears and detachment.
Keywords: retinal detachment • myopia