12 Feb Posterior Vitreous Detachment (PVD)
The jelly that fills the back of our eyes is called the vitreous. When it pulls away from the back of your eye it is called a posterior vitreous detachment (PVD) or a posterior vitreous separation (PVS). These are different words for the same thing.
Odds of Having a Posterior Vitreous Detachment
The chances of having a PVD are about equal to your age. A 60 year old would have a 60% of already having a PVD and an 75 year old would have a 75% chance. Most with a new PVD have a new floater they notice for a few days or some for a few months and then hardly notice it again after that.
However, more annoying or even sight threatening complications can occur so it is important to take this seriously and be seen promptly by your eye doctor when this happens.
What is the Vitreous?
The vitreous is structured when we are developing in the womb and has an important job to do. It is made up of water and long organized chains of collagen and hyaluronic acid. These form a scaffolding that allows blood vessels from the optic nerve to grow along chains across the middle of the eye. The blood vessels provide energy and nutrients to build your lens. When the lens is finished, the blood vessels dissolve and disappear. What a work of wonder!
Floaters in the Eye
Once the blood vessels dissolve, the scaffolding of your vitreous has completed its entire life’s work so the body does not maintain it. Slowly, over the course of time, your vitreous becomes less formed, and more like a liquid. At an intermediate stage, thick areas of vitreous float through liquid areas. These thick areas cause floaters you can see as they cast a shadow on your retina. This type of floaters is annoying, but not dangerous.
Symptoms of Posterior Vitreous Detachment (PVD)
Eventually, your vitreous becomes so liquid it pulls away from the retina. This causes the sudden appearance of a large new floater or veil. A new floater often looks like a bug flying in your peripheral vision.
As your vitreous is pulling away, it can cause flashes of light that look like a lightening bolt shooting across your eye.
The flashes do not shimmer or sparkle for any extended period of time. They quickly flash and then are gone for some period of time before another flash happens. There are other conditions that cause flashes that last for several minutes or shimmer.
It is important to contact your eye doctor if you develop symptoms of a posterior vitreous detachment and be seen that day or early the next day if it is quite late.
Treatment for Posterior Vitreous Detachment (PVD)
Most patients do not require any treatment for their PVD. It is prudent to decrease vigorous exercise and activities that result in jarring head movements until your eye doctor tells you the posterior vitreous detachment process is complete. Once this happens you can return to such activities. If complications result or the floaters remain very problematic, then treatments could be employed for those specific problems.
Floater Complications of Posterior Vitreous Detachment
If the vitreous pulls away cleaning from the retina you will juat have a new floater. Sometimes it is small and gravity pulls it out of your line of sight. Other times, the floater(s) stays tethered near the center of your vision, but over the course of time your brain learns to not see them anymore as they fade into the background noise of what you see each day.
You can always make yourself see them if you cover your other eye, stare at a bright white wall or brilliant blue sky and move your head back and forth.
On rare occasions, the floater is large, annoying, and stays right in the center of your vision for many months. If this happens, you can see a retinal specialist to find out the risks, benefits, and alternatives to having the floater removed or lasered.
Blood Vessel Complications of Posterior Vitreous Detachment
If the vitreous does not let go of the retina cleanly, it can tear a blood vessel or make a hole in the retina as it pulls away. The torn blood vessel will bleed. The blood will look like a spider web floating if the blood congeals or like hundreds of individual small floaters if the blood dissolves and separates into individual red blood cells. This blood begins clearing on its own once the bleeding stops.
Retinal Tear Complications of Posterior Vitreous Separation
Some retinal tears heal themselves, while others, called horseshoe tears, are held open by the vitreous. Fluid can enter through these tears and detach your retina. This is a serious eye condition that can significantly harm your eye.
If your eye doctor sees a horseshoe tear, they or a retinal specialist can laser around the tear and arc weld it down so that fluid can’t enter the tear and detach your retina.
This is why it is important to see your eye doctor promptly if you hare having symptoms of a posterior vitreous separation. It is to prevent a subsequent retinal detachment. If the retina is already detaching when you seek care, a retinal surgeon can repair the retina, but it is better for you and your vision to prevent it in the first place.
Epi-Retinal Membrane (Macular Pucker)
When the vitreous pulls away from the retina, it stirs up a healing response in the eye. Cells deep and quiet in the retina will activate in some patients and spread out on the surface of the retina causing a thin layer of scar tissue to form. This is called an epi (on top of) retinal membrane (scar). Fortunately, this is rare.
If the scar tissue contracts, it causes the retina to pucker or wrinkle (macular pucker). A macular pucker can cause blurry vision and make straight lines appear curved or warped. If this has a significant impact on your vision, retinal surgeons can often peel this membrane off (membrane peel) to help the retina smooth back out.
Causes of Posterior Vitreous Detachment
Most PVDs happen spontaneously as part of a long life. Anything that swirls or stretches the vitreous has a chance of making the vitreous separate at a slightly younger age than it would have otherwise. Any surgery inside the eye, like cataract surgery, has some chance of speeding the process.
Trauma to the eye can speed the onset of your posterior vitreous detachment. Inflammation or bleeding inside your eye can also hasten the process.
Nearsighted patients have an eye that is longer than normal. This puts the vitreous on stretch and can make your PVD happen at a younger age. In addition, those that are near sighted are considered to be at greater risk for the retinal detachment complications that occasionally come from a PVD.
This would be true even if you have had LASIK to cure your nearsightedness, as you would still have a long eye even though you aren’t near sighted anymore.
Your vitreous only separates once in in each eye during your lifetime. Therefore, if you already have a PVD, then cataract surgery, trauma, etc. cannot cause it to happen again.
Posterior Vitreous Separation Protects Diabetics
A posterior vitreious separation prevents many of the bleeding complications that can come to the eye as a result of diabetes. For this reason, doctors have experimented with medicines that could cause the vitreous to separate in diabetics at a younger age, but no mainstream treatment has emerged. Retinal specialists separate the vitreous and remove it (vitrectomy) from some diabetics with significant and reoccurring eye hemorrhage problems.
If I can answer any other questions about posterior vitreous separation please leave a comment or schedule a time to meet with me.