On Sep 12, 2021 this invited lecture was presented to the European Society of Retinal Specialists (EURETINA) on the subject of vitreous, the gelatinous structure that fills the center of the eye. During aging, vitreous gel liquefies (accelerated in myopia) and eventually collapses and pulls away from the retina, an event called Posterior Vitreous Detachment (PVD). Anomalous PVD can feature splitting between the lamellae of the peripheral vitreous, causing vitreoschisis. This lecture describes how vitreoschisis can promote recurrent retinal detachment via the action of cells embedded in the outer vitreous, called hyalocytes.