Information - Floaters and Flashers

By middle age, most people see small, dark shapes that appear to float in their field of vision. The shapes may be round, oval or very irregular. These are called floaters. They are particles in the vitreous body, a jelly-like substance that fills the inside of the eye. Floaters appear in the field of vision because they cast shadows on the retina and are more obvious against a clear background. They move quickly with eye movement and drift away when eye movement stops. Some floaters can interfere severely with vision, while others are barely noticeable.

Flashes

Small flashes of light may be seen with or without the appearance of floaters. Flashes are usually caused by the vitreous body tugging on the retina. Flashes may last for a few seconds or several minutes, and can occur off and on for weeks or months. They are usually seen at night or in poor lighting.

Floaters and Flashes

The appearance of both floaters and flashes may happen as a result of the normal ageing process and as the vitreous body shrinks, it becomes less jelly-like and more liquid. Floaters appear in the watery vitreous, and the shrinking vitreous often separates from the retina. This is known as “posterior vitreous detachment” and occurs in about half of people by the age of 55. When this happens, a large floater and multiple flashes are usually seen. Sometimes, the vitreous body is more firmly attached and pulls away a piece of the retina as it shrinks. This can cause slight bleeding, triggering what people often describe as a “shower” of new floaters. When these retinal tears happen, fluid can escape, pushing the retina off the inside wall of the eye. This is known as retinal detachment, which is a serious threat to sight and surgery is need to reattach the retina.

 Diagnosis

See your optometrist if new floaters appear, with or without sudden light flashes. Any loss of peripheral (side) vision should be investigated without delay.

Treatment of Floaters and Flashes

Large and persistent floaters that obstruct vision can be surgically removed during a procedure known as a vitrectomy. As possible complications can be serious and may not be worth the risk, vitrectomy surgery is recommended only in unusual cases. Complications can include retinal detachment, cataract formation, glaucoma and ultimate loss of vision in the operated eye, among other possible side effects. However, vitrectomy surgery may be an acceptable option if floaters drastically affect driving, reading or the ability to work.

Light flashes don’t need treatment if the retina is not torn. If a retinal tear is present, however, early treatment to seal it can prevent retinal detachment.

A tear may be treated by either or both of the following:

·        Laser treatment (photocoagulation). As tiny burns made with the laser heal, the scar tissue seals the tear.

·        Cryotherapy (freezing treatment). Extreme cold freezes through to the retinal tear. This creates scar tissue that seals the hole.

Both treatments are usually performed using local anaesthesia and can cause slight discomfort. There is a small risk of reduced vision and a possible need for further treatment, including retinal detachment surgery. However, this risk is much lower than the risk of vision loss due to leaving the retinal tear untreated.