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AD Springer, DH Kauffmann Jokl; A Theory and Model of Retinal Detachment in Retinopathy of Prematurity . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1245.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Virtual engineering models were used to evaluate the effect of fibro-vascular ridge thickness, stiffness and penetration into the underlying retina on retarding retinal expansion and causing a retinal detachment as the eye grows. Methods: Inflation of an elastic sphere with a nonlinear finite element analysis was used to simulate retinal stretch and surface area enlargement caused by eye growth. Sphere constriction and reduced sphere volume reflected retinal detachments. Spheres with and without an annular ridge along their inner surface were compared. We also assessed the role of ridge stiffness on model deformation using a 40-fold range of ridge:retina stiffness. Additional models were used to determine sphere deformation when cross sectional ridge area and ridge height were varied by a factor of 2. Models were also used to explore sphere deformation as the region having increased stiffness was varied to progressively include the ridge and retinal tissue underlying the ridge. Results: A ridge on the inner surface of the model produced a retinal detachment like deformation along the outer surface of the sphere. This detachment was aligned with the ridge. Just the presence of a ridge having the same stiffness as the remaining sphere was sufficient to produce a detachment. Ridges having higher elevations, with respect to the inner surface of the sphere, increased the magnitude of the detachment. Analysis of ridge penetration into the wall of the sphere indicated that detachment increased as the stiff ridge penetrated deeper into the wall of the sphere. Even in the absence of a ridge, a stiffened annulus of material within the sphere wall was sufficient to cause a detachment. Conclusion: An annulus of stiffened tissue within, or on the surface of the retina, will deform and detach the retina in the growing eye. Such a detachment will occur even when the ridge has the same stiffness as the underlying retina. Our hypothesis is that the ridge initially induces a subclinical detachment. As this detachment enlarges, retinal separation from the RPE promotes neovascularization along the ridge. Neovascular elements extending from the retinal surface into the vitreous exacerbate and accelerate the detachment. Implicit in this model is that the promotion of neovascularization by the avascular anterior retina is not the initial cause of the detachment. Instead, retinal deformation caused by the ridge is the principal cause of detachment. Devising methods that release the ridge from the retina or segment the ridge may prevent subtle retinal detachment, pathological neovascularization and obviate the elimination of the avascular retina.
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