[Incidence of lack of posterior vitreous detachment in retinal detachment caused by flap tear in the elderly].

I investigated whether posterior vitreous detachment is invariably associated with retinal detachment in the elderly caused by flap retinal tears. Of 97 eyes which underwent vitrectomy, Weiss' ring was not observed in 10 eyes during both the preoperative slit lamp microscope examination and the intraoperative surgical microscope observation. I proved by surgically detaching the posterior vitreous in 5 out of those 10 eyes that the posterior vitreous had not yet become detached before the operation. My results suggest that posterior vitreous detachment may not be associated with 5 to 10% of cases of retinal detachment caused by flap retinal tears.