We report a patient with cognitive disorder who had a rhegmatogenous retinal detachment (RRD). A 17-year-old Japanese man presented with a RRD with a vitreous hemorrhage in his right eye. An unusual vertical splitting of the macula accompanied by a giant retinal tear was observed intraoperatively. The retina was successfully reattached by pars plana vitrectomy with silicone oil tamponade and scleral buckling. Visual function appeared to have improved from the behavior of the patient. Although the precise mechanism causing the break which split the macula was not determined, self-inflicted blunt trauma to the eye was suspected.