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R.I. Park; Intraretinal stresses during internal rotation saccadic eye movements in pre– and post–vitrectomy eyes: a dynamic finite element simulation . Invest. Ophthalmol. Vis. Sci. 2004;45(13):2063.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:To compare the location and magnitude of intra–retinal stresses generated during an internal rotation saccadic eye movement before and after vitrectomy. The effect of vitrectomy on intraretinal stress generation is evaluated by finite element modeling. The change in the location and magnitude of intraretinal stresses aids in quantification of the risk of retinal tear and detachment before and after vitrectomy. Methods:A 3–dimensional finite element model of the human eye is created using ALGOR software. The model is anatomically correct and based on an idealized human eye. A 30 degree saccadic internal rotation is applied to the eye with and without the vitreous humor. The model is accelerated over 19 msec, remains at constant velocity for 21 msec and is decelerated for 19 msec. The location and magnitude of the intraretinal stresses is recorded. The pre– and post–vitrectomy models are compared. Results:Internal rotation of the model human eye with intact vitreous demonstrates a peak von Mises stress of 242 Pa during the acceleration phase located in the supero–temporal and supero–nasal quadrants. During the constant velocity phase, the peak stress is 490 Pa located medially. During deceleration the peak stress approaches 1 kPa and is located in the posterior pole. In the post–vitrectomy eye, the acceleration phase demonstrates a peak von Mises stress of 199 Pa located medially. The constant velocity phase shows a peak stress of 207 Pa located medially. The deceleration phase shows a peak stress of approximately 2 kPa located inferiorly. Conclusions:The dynamic finite element analysis of pre– and post– vitrectomy eyes undergoing a medial saccadic eye movement demonstrates clear differences in the location and magnitude of intraretinal stresses. The change in the location and magnitude of the intraretinal stresses may play a role in the development of retinal detachment before and after vitectomy surgery.
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