Eye Floaters are a frequent reason for urgent eye appointments at my Mississauga Eye Care clinic, so I thought it would be a good idea to shed some light on the subject. Floaters can be of differing sizes and shapes. They are visual disturbances that are usually intermittent or temporary in their appearance.
Floaters have been described as spots, cobwebs or mosquito-like and appear to move when the eye moves. Floaters are most often visible when looking at a bright sky, pale-colored wall or during reading activities. They can be associated with flashes of light, but more on this later.
Floaters and Vitreous Detachment
Floaters that come on suddenly should be assessed without delay. Recent-onset floaters are most commonly caused by a posterior vitreous detachment. The vitreous is the gel-like substance that fills the eye. After the age of 50, the vitreous starts to contract and often detaches from the posterior surface of the eye – the retina. When it does, parts of the vitreous may be opaque, not letting light shine through it. This is what causes floaters to be seen; it is from the shadows they create on the photographic film of the eye (retina). Any perceived visual image that does not truly represent something in the real physical world is termed ‘entopic phenomenon.’
Floaters tend to fade with time and on their own are usually no more than a minor visual nuisance. The floaters caused by small opaque particles in the gel of the eye actually don’t disappear, the brain just starts to ignore them so they are no longer perceived. Some vitreous detachments result in large floaters that can interfere with vision greatly.
In very rare cases of large eye floaters associated with significant, prolonged visual disturbance, the vitreous can be removed through a complicated vitrectomy surgery, where the vitreous is replaced with saline. This surgery does carry a risk of serious eye infection and retinal detachment, however. It is only performed in the worst cases of floaters that are seriously interrupting a patient’s vision.
Floaters and Retinal Detachment
In less than 10% of cases, a vitreous detachment can lead to sight threatening retinal damage, in the form of retinal tears or a retinal detachment. When the retina detaches, you cannot see. Therefore, all cases of recent-onset floaters should be investigated to rule out retinal breaks, tears and detachments. Retinal tears and detachments can also produce floaters, most commonly due to pigment release or blood from a torn retinal blood vessel leaking into the vitreous of the eye. Retinal detachments are treatable, with varying degrees of success, depending on how soon treatment is initiated and how much of the retina has detached. If the macula, that part of the retina responsible for central, fine vision, is involved, it only takes 24 hours for permanent vision loss to result. So I will remind you again, this is why any recent-onset of floaters or obstructed vision needs to be assessed urgently.
Retinal detachments or tears are treated surgically in a number of ways, including laser, cryotherapy (local tissue freezing), and with gas tamponades and scleral buckles (this is like an elastic band wrapped around the back of the eye).
Floaters and Diabetes
Floaters can also be a symptom of an intraocular bleed, which is most often the result of diabetes in cases of retinal disease. Diabetic patients are reminded to have annual eye exams for detecting disease early and ensuring timely treatment.
When do we closely monitor eye floaters?
In the case of recent-onset floaters where no retinal breaks, detachments or bleeds are found, I will typically monitor the patient for 3 months. We will perform a dilated fundus exam at the initial visit, again at 1 month and then at 2 or 3 months from initial onset of symptoms. This is usually the course of assessment for posterior vitreous detachment.
Floaters that have been present chronically, have not changed recently, and have associated with no eye disease, usually require no further investigation other than routine eye exams.
Floaters and Myopia.
If you are nearsighted, or myopic, you may have experienced eye floaters, most often described as ‘hair-like’ disturbances, periodically throughout life. These floaters are due to varying consistency within the gel-like structure of the eye. This inconsistency casts shadows on the retina that are typically seen against bright, plain backgrounds. It is important to note that patients with high myopia are more prone to retinal thinning, which can lead to the development of retinal holes, tears and retinal detachments. Therefore, routing monitoring of the eyes is advised, and is often best done thru a dilated fundus exam.
See our comprehensive list of common eye conditions to learn more about conditions that may affect your vision.