The eye’s posterior segment is filled with vitreous, a gel-like substance that is attached to retina, nerve, and vascular structures. Millions of fine collagen fibers are intertwined within the vitreous, and the vitreous is mostly composed of water. As we age the collagen fibers slowly shrink, and the ensuing changes in the vitreous cause traction upon the retina. Usually the collagen fibers break, allowing the vitreous to separate and shrink from the retina. This process causes a vitreous detachment, i.e., the vitreous becomes separated from the structures in the back of the eye.
The vitreous has two main functions:
to act as a shock absorber to redistribute forces within the eye
to serve as a transport medium occupying the major volume of the eye, thereby transmitting light on the retina (located immediately behind the vitreous)
As mentioned above, the back surface of the vitreous is in contact with the retina, optic nerve, and retinal blood vessels. However, in most eyes the vitreous will eventually pull away or separate from the retina. This event constitutes a posterior vitreous detachment and is considered a normal aging process.
What are the symptoms of Posterior Vitreous Detachment?
Symptom 1 – Floaters:
An individual may see a range of floaters– a few to hundreds of dark spots or objects”floating” in the field of vision. These floaters may represent bleeding inside the eye, torn retinal tissue, or normal aging changes in the vitreous. Floaters have also been described as”spots and dots,””a cloud of smoke,” or a”swarm of bees.”;
Symptom 2 – Flashes:
Lightning flashes are generated by the vitreous tugging on the retina. A posterior vitreous detachment is typically associated with the visualization of light flashes. Patients have described these flashes as”a sparkle or twinkle,””a disco light,” or”fire flies.”
Symptom 3 – Decreased Vision:
Decreased vision can occur secondary to bleeding inside the eye or a retinal detachment. With retinal detachments, central vision may be normal early on, but patients may note a progressive”curtain, veil, or fog” which may obscure peripheral and central vision.
Who is at risk for Posterior Vitreous Detachment?
Most people will have a posterior vitreous detachment by 70 years of age, and some will develop this phenomenon sooner. It is important to note that these patients may otherwise be healthy without associated eye disease. Biochemical changes of the vitreous may be associated with eye conditions.
Additional factors that may increase that risk for a posterior vitreous detachment:
history of cataract surgery or other eye surgeries
inflammation inside the eye (such as from blunt trauma, car accident, or fall) or bleeding inside the eye.
Are Posterior Vitreous Detachments Dangerous?
For the majority of those who have a posterior vitreous detachment, there is no danger involved. The only residual symptom afterwards may be the indefinite persistence of a few floaters.
However, 8-15% of those who have a posterior vitreous detachment with symptoms of floaters, flashes, or decreased vision also have an associated retinal tear. Up to 50% of patients with one or more risk factors and a symptomatic posterior vitreous detachment will develop a retinal tear.
It is important to have a dilated eye exam as soon as possible when one notices the onset of flashes and floaters. The symptoms of a benign vitreous detachment are very similar, if not identical, to the symptoms of a retinal tear or early detachment. A vitreous detachment requires no medical or surgical intervention, but a retinal tear or retinal detachment requires emergency surgery. With the onset of new floaters or seeing flashing lights, it is important to have the eye examined.
What is the treatment for Posterior Vitreous Detachment?
If a posterior vitreous detachment has occurred without associated retinal problems, no therapy is indicated. The vitreous will continue to age and liquefy and floaters will usually become less noticeable. With time, most people’s symptoms disappear entirely.
If a retinal tear has occurred, the doctor will recommend treatment of the tear with laser, cryopexy (a freezing treatment), or surgery. A retinal detachment can be repaired by a surgical procedure here in Atlanta.