We developed an experimental model for a posterior penetrating eye injury that resulted in traction retinal detachment in 21 rhesus monkey eyes. The standard injury was an incision through the pars plana with vitreous prolapse and incarceration; the wound was then carefully closed with microsurgical techniques. At one to two weeks after injury, detachment of the posterior vitreous occurred and detachment of the retina occurred between seven and 11 weeks. The development of retinal detachment was related to traction on the peripheral retina over the vitreous base; and to the contraction of epiretinal membranes on the peripheral and equatorial retina. Our study supports clinical observations on the importance of blood in the vitreous in the development of vitreous traction and traction retinal detachment after a posterior penetrating injury.