An acute onset of suddenly appearing entopsias with or without light flashes usually is caused by a posterior vitreous detachment with collapse. Ordinarily this is an innocuous process. However, a study of 84 such patients revealed that three types of complications may be encountered: retinal breaks, intravitreal or retrovitreal hemorrhages or both, and vitreoretinal traction at the posterior pole of the fundus.
A retinal break was suffered by 11% (nine) of the patients and blood was found intravitreally or retrovitreally in each. There were four patients with intravitreal or retrovitreal hemorrhage or both who did not suffer a retinal break. Two patients developed vitreoretinal traction at the posterior pole. Visual acuity and symptoms improved after the adherence separated, although one patient was left with some wrinkling of the internal limiting membrane of the retina.
Jaffe NS. Complications of Acute Posterior Vitreous Detachment. Arch Ophthalmol. 1968;79(5):568-571. doi:10.1001/archopht.1968.03850040570012