Vitreous degeneration, which is sometimes also known as a posterior vitreous detachment or PVD, is an eye problem that happens when the vitreous membrane on the surface of the eyeball detaches from the retina temporarily. This can cause affected people to see flashes of light, to have clouded vision, and to experience “floaters,” which are basically bright spots that seem to be floating in space. The condition is sometimes a regular consequence of aging, and is particularly common in elderly humans and older domestic animals. It might also be caused by an accident or some sort of trauma. Dogs and cats are usually thought to be particularly at risk, though PVD has also been documented with some regularity in a range of farm animals. In most cases the condition can be treated, though eye surgery is often required in advanced stages.
Why Degeneration Happens
The eyeball of humans and many animals is made of several layers of gelatinous substances that function together to filter light and translate sights and objects into meaningful vision. The vitreous membrane is one of these layers, and is usually made of collagen. It surrounds the eyeball almost completely and is anchored in two places: to the retina at the front of the eyeball, which is where most vision happens, and also at the vitreous base, back where the optic nerve connects the eye to the brain. PVD happens when the front connection weakens or slips. It is generally very rare for the membrane to become detached in the back.
The exact causes of vitreous degeneration are a matter of some debate, but the condition does tend to be most common in adults over the age of 50 and is often believed to be a regular part of aging. Some researchers also say that there may be a link between this type of problem and the occurrence of uveitis, an inflammation of the eye. Any injury that affects the integrity of the vitreous membrane itself can also lead to a decreased ability to protect the retina and hold it in place, which sometimes leads to detachment in its own right. Temporary detachment is sometimes a side effect of certain eye surgeries, for instance, but unless the damage is really extensive things will often realign themselves in these cases.
Who Is at Risk
Older adults are the most at risk for developing temporary detachment issues as the bonds holding the membrane to the retina naturally tend to weaken as time passes. Dogs and cats are almost as susceptible to the condition as humans, too, though in these cases age isn’t always as much of a factor; puppies and kittens are often as likely as their older counterparts to begin experiencing detachment. Horses, pigs, and cows are some of the other animals that are considered by many veterinary experts to be “high risk” for this condition.
People often first begin to suspect that they have PVD when they experience occasional clouded vision. Many will also fell like they see flashes of light, particularly when opening and closing their eyes, and “floaters” are also very common. Floaters are rings or baubles of light that dance across a person’s visual landscape, but they exist only in the eye — no one else can see them and they aren’t actually there in space. It’s often the case that these symptoms intensify when people are moving their heads very quickly.
It can be a lot harder to tell when animals are suffering from PVD. Sometimes they begin to lose their balance or misjudge spaces, walking into walls or falling off of steps, for instance. Other times there are no visible symptoms aside from crankiness and general irritability, and the condition has to be noticed and diagnosed by a veterinary eye specialist. This is one of the reasons many veterinarians inspect animals’ eyes as part of routine health checks.
Most initial incidents of this condition aren’t permanent, and in some cases they will fix themselves — with time the membrane can actually reattach itself, in other words. This isn’t always the case, though, and things sometimes can get much worse if left untreated. The condition can progress to the point that the retina itself becomes detached, which can lead to blindness. As such, it’s usually a good idea for anyone who thinks they may have this or some other vision problem to visit an eye specialist to get to the root of whatever is going on.
Treatment in both humans and animals requires careful monitoring in order to track progress. Ophthalmologists can sometimes make use of laser surgery to help stabilize the position of the retina, and this is especially true when the underlying cause for the eye problem is an injury of some sort. The surgery not only helps to prevent the retina from becoming detached, but also can make it easier for the membrane to begin regenerating and healing itself.
Regular eye exams are really important since early detection is often essential to preventing lasting damage. People are usually advised to get their eyes checked every couple of years, even if they don’t think they have any real problems. Early treatment and lifestyle changes in the beginning can save a lot of grief, expense, and pain later on.