On the influence of an equatorial cerclage on closure of posterior retinal detachment

A mechanics-based mathematical model of an eye possessing a posterior retinal detachment is presented for the case where an encircling scleral buckle (a cerclage) is sutured around the equator of the eye. The mechanical behaviour of the retina and the globe, both before and after applying the cerclage, is studied. An energy formulation yields the self-consistent equations of equilibrium and boundary conditions of the ocular system, and analytical solutions are established for the scleral buckle, for the globe and for the detached segment of the retina. Results of numerical simulations based on the solutions unveil characteristic behaviour of the ocular system, and demonstrate the influence of the scleral buckle, as well as of the pressure difference between the vitreous cavity and the subretinal space, on the deformation of the eye and on closing the region of retinal detachment. The results indicate that a scleral buckle encircling the equator, normally used for closing retinal tears and associated retinal detachments in the immediate vicinity of the buckle, can have a marked influence on bringing the detached segment of neurosensory retina back into contact with the retinal pigment epithelium, even for detachments at the posterior of the eye.