Visual floaters are some of the more common complaints optometrists hear about every day. They show up as small spots with an appearance of small insects or worms that seem to drift in and out of our vision. Sometimes they even look like spider webs. If you've never experienced them before, it can be quite frightening.
Floaters are a normal part of aging. The vitreous humor in the back of the eye is a clear gel that takes up about 90% of the volume in the eye and help keeps the eye's shape. It also helps protect the eye from trauma by absorbing some of the energy from a blunt force that may hit the eye.
The vitreous gel degrades over time into more of a liquid type gel. When this happens, pieces of collagen in the gel start to form little deposits and strands as they sit inside
the gel liquid and that's what gives the appearance of floaters, as these strands drift back and forth. When light enters the eye and hits these collagen deposits, it
causes the light to scatter giving a shadow image on to the retina in the back of the eye. This is why we see floaters the way that we do. Floaters are a normal part of aging and once you reach age 60 or greater, you have a 25% chance of having floaters and if you're fortunate enough to reach the age of 80, you'll have a 70% percent chance of experiencing floaters.
There are some eye conditions that may increase your chances of experiencing floaters. Being nearsighted or myopic is one. Highly myopic eyes are a little bit longer than normal and the vitreous gel starts to degrade sooner. Nearsighted people see floaters more often especially when you go outside and look at the blue sky or look at at a large white or grey background like a large blank wall wall. This is also why eye doctors are very concerned about children developing high myopia as they may lead to retinal detachments as explained later on.
Another important factor about floaters is it's an indication of an increased risk of a retinal tear or a retinal detachment. The vitreous inside the eye has an outer layer that's made of more collagen called the vitreous cortex and it acts like a shell but is attached to the retinal nerve fiber layer in the back of the eye. As the vitreous gel starts to degrade and turns more liquid, it peels away from the back of the retina and can sometimes tug on the retina. This can cause the outer edges of the retina to start coming off and when that happens it can cause a little tear or even a complete hole. It can even rip off the entire retina from the back of the eye. This is called a complete retinal detachment and is considered a serious eye emergency.
Retinal detachments often occur suddenly, but sometimes there are warning signs. Patients often complain of flashes of light that accompany floaters. They'll complain of a bright flash of light in their eye off to the side like a camera flash or a lightning bolt. These flashes occur as the vitreous tugs on the retina as it's starting to peel off. This tugging causes a physiological excitation of the retina called a light phosphene that our brain interprets that as a flash of light.
If you're experiencing any of those signs - flashes of lights and floates, you need to see an eye doctor as soon as possible to be checked for any retinal tears or detachments.
Another concern with flashes and floaters are changes to the macula. The macula is the central part of the retina that contains the rod and cone cells that gives us our sharpest vison. If the vitreous starts to peel away from the macula it can tug on the macula and cause the development of what's called macular edema which are small cysts that develop in the retina causing our vision to be blurry. Another serious consequence of this pulling at the macula is the development of a macular hole which is the same thing as a retinal hole in the peripheral retina, but it's occurring at the macula. This is a serious threat to your vision and must be watched and treated. Macular holes cause central vision loss which means you can no longer see directly ahead making it very difficult to read or drive. Some patients may even become legally blind.
Floaters are managed by dilating your eyes and observing your retina for any tears or holes. Most floaters are not serious enough to require treatment. While they can be a
annoying, floaters will generally drift down due to gravity and out of your field of view. Patients also adapt to them and will not notice them after a few weeks. Very large floaters can drift right in front of the central part of your vision and it can stop you from seeing correctly. They can certainly interfere with driving or school.
In these cases there are some treatments performed by retina specialists which may alleviate the worst floaters. The first is a vitrectomy. The retina surgeon will remove the gel from inside the eye. It is sucked out while simultaneously putting in new fluid in the eye to keep the eye's shape and maintain internal eye pressure. This is a challenging procedure with some complications. Usually not recommended unless your floaters are casing significant vision loss. Newer less invasive treatments use lasers
to hit the floaters and cause them to shrink. The success of this procedure is limited by the location and size of your floaters.
The important thing to remember about floaters, and especially floaters and flashes, is to make an appointment to see an eye doctor and make sure they are not a sign of more serious retinal damage that can compromise your vison.