Posterior vitreous detachment (PVD) is a common eye condition in which jelly-like matter in the eye, called the vitreous gel, or vitreous humor, shrinks and detaches from the retina at the back of the eye, leaving one or more spaces. In most cases, this disorder is not serious and does not cause any significant loss of sight. Eye problems related to PVD commonly occur in individuals over the age of 65.
The cause of posterior vitreous detachment is related to changes in the vitreous gel that occur in older individuals. In a young person, this gel typically fills the middle part of the eye, pressing on the retina at the back of the eye, and helping to keep it in place. As individual ages, the consistency of the gel tends to change, becoming less viscous. At the same time, the mass of the gel tends to reduce slightly, so that it no longer completely fills the space it used to occupy. As a result, the mass of gel may pull away from the retina in one or more locations, leaving spaces at the back of the eye.
In the majority of posterior vitreous detachments, the retina is not damaged and the individual retains normal vision. The most common symptoms of posterior vitreous detachment are vitreous floaters, which are small particles of pigmented material that have sloughed off the retina into the vitreous gel. These floaters are usually experienced as small dots or lines in the patient’s field of vision. They may be annoying, but they do not generally lead to any significant visual impairment. The vitreous floaters usually disappear, or at least become less noticeable, over a period of several weeks, or a few months.
In a few cases, more serious eye conditions may be experienced as complications of posterior vitreous detachment. As the vitreous gel detaches from the retina it may tear the retinal tissue, or even cause the retina itself to detach from the back of the eye. Such complications, especially if accompanied by bleeding in the eye, may lead to severe eye diseases, and in rare cases even blindness.
Retinal tears may be repaired using laser eye surgery. Where a posterior vitreous detachment has caused a retinal detachment, the patient may require an operation to take the vitreous gel out of the eye and replace it by injecting a special fluid into the eye. This fluid replaces the vitreous gel and presses the retina back into place.