Posterior vitreous detachment (PVD)
What a PVD is, what symptoms to expect, and when to seek urgent advice.
What is a PVD?
The vitreous is a clear gel that fills the back of the eye. It is attached to the retina until, with age, it degenerates and peels away. This separation is called a posterior vitreous detachment. It is common and occurs naturally — in short-sighted people it tends to happen earlier (as early as the forties or fifties, rather than seventies and eighties).
Symptoms
As the gel liquefies, floating clumps cause new floaters. As it separates from the retina you may notice flashing lights — usually brief sparks at the edge of vision, most noticeable in dim lighting and on eye movement.
Is a PVD serious?
In the vast majority of cases a PVD is harmless. Floaters typically become much less obvious over time as the brain adjusts and filters them out.
Sometimes, during the separation, the vitreous gel can be stuck to a patch of retina and cause a retinal tear as it pulls away. If fluid tracks through the tear behind the retina, it can cause a retinal detachment.
When to seek urgent advice
Contact an eye doctor urgently if you experience a sudden shower of new floaters, persistent flashing lights, or a shadow or curtain across your vision. These symptoms may indicate a retinal tear or detachment that needs prompt treatment.