POSTERIOR VITREOUS DETACHMENT AND FLOATERS

Posterior Vitreous Detachment (PVD) is a natural aging change that occurs during adulthood, when the vitreous gel that fills the eye separates from the retina.

The vitreous, a gel-like substance, accounts for 80 percent of the volume of your eye. It fills the interior of your eye and helps to preserve its round shape.

Tiny collagen fibers secure the vitreous to its base near the front of the eye. They also secure it to the optic nerve and the retina in back of the eye.

But, over time, the collagen fibers degrade, and the vitreous gradually liquefies. This destabilizes the gel, and the vitreous contracts, moving forward in the eye and separating from the retina.

When this happens, you see new floaters (caused by stringy strands in the vitreous casting shadows on the retina). Often, they’re accompanied by flashes of light — usually in your peripheral vision — and especially visible in the dark.

The flashes and floaters generally subside within one to three months, and 85 percent of those with posterior vitreous detachment experience no further problems.

Causes

Over time, the vitreous gel that fills the eye becomes liquid and condenses (shrinks) due to age and normal wear and tear. Eventually it cannot fill the whole volume of the eye’s vitreous cavity (which remains the same size during adulthood) and so the gel separates from the retina, located at the very back of the eye cavity.

Over the next 1 to 3 months, the vitreous gel further condenses and the sides of the gel also separate from the retina until the PVD is complete and the vitreous gel is attached to the retina only at the vitreous base (see Figure 1). Clear vitreous fluid fills the space between the condensed vitreous gel and the retina.

If a PVD progresses gently, gradually, and uniformly, the symptoms are typically mild. However, if the forces of separation are strong or concentrated in a particular part of the retina, or if there is an abnormal adhesion (sticking together) between the vitreous gel and the retina (such as lattice degeneration), the PVD can tear the retina or a retinal blood vessel.

Flashes and floaters are typically more obvious when PVD is complicated by a retinal tear or vitreous hemorrhage. These conditions can lead to further complications, such as retinal detachment or epiretinal membrane, which can result in permanent vision loss. However, about 85% of patients who experience PVD never develop complications and in most cases, the flashes and floaters subside within 3 months. 

Risk Factors

The risk factors for vitreous detachment include:

• Older age.
• Nearsightedness/High myopia
• Past eye trauma.
• Prior cataract surgery.
• Vitreous detachment in one eye.

Treatment and Prognosis 

PVD is non-sight-threatening and the symptoms subside in the vast majority of patients. Most patients no longer notice flashes after 3 months and floaters tend to improve. No specific treatment is needed for PVD. That said, complications of PVD are rare but can be serious and require urgent treatment, such as laser for a retinal tear or surgery for a retinal detachment. For this reason, one or more checkups are recommended within 3 months after the onset of PVD. .