Posterior Vitreous Detachment
Complete PVD: Separation of vitreous from the retina and optic disc.
Incomplete PVD: Full or partial separation from fovea but residual attachment to optic nerve and mid-peripheral retina.
Vitreoschisis: or anomalous PVD whereby there is liquefaction (synchysis) more than vitreoretinal separation.
Vitreous syneresis: Collapse of the vitreous gel. Goes hand in hand with synchysis in the gradual process of vitreous separation of PVD.
Useful information about PVD:
PVD starts around fovea.
Vitreous is most strongly attached at vitreous base and optic disc.
Weiss Ring = separation of vitreous from optic disc evident on slit lamp examination.
Five evidence based answers for PVD / retinal breaks (Retina Specialist March 2021)