From All About Vision
In most cases, posterior vitreous detachment is caused by normal aging changes in the eye. With time, the vitreous contracts or shrinks, and also becomes less like a gel and more like a liquid (a process called vitreous syneresis). When this occurs, the vitreous and collagen fibers within it, pull away from and eventually detach from the retina.
Other causes of PVD include:
- High nearsightedness
- Trauma to the eye
- Inflammation of the retina
- Cataract surgery or vitreoretinal surgery (vitrectomy)
Posterior vitreous detachment is diagnosed through a comprehensive eye exam. Expect a dilated eye examination. This adds time to the eye exam and disrupts vision for 4-6 hours, but is necessary in order to get a good view of the retina.