What are floaters?
Floaters are tiny fragments which some people see in their field of vision. They can vary in shape and size and appear to be present whenever the individual looks at an object, image or another person. Floaters usually appear as small black dots, small shaded spots, larger dots and long, thin strands. They are present in the vitreous jelly portion of the eye and cause shadows to be cast on the retina. It is often the case that these shadows are seen when you attempt to look at something; usually floaters are not troublesome.
What causes floaters?
Floaters often develop as an element of the normal process of ageing. They tend to be most common in people over the age of 60, although they can affect younger people. Floaters are usually caused by changes to the vitreous jelly portion of the eye. As you age the vitreous jelly can become harder and this means that strands of collagen (a protein) can become visible when you attempt to look at things. Light is usually able to pass straight through the vitreous humour to the retina at the backside of the eye, but if there are floaters in the vitreous humour this will cause shadows to be cast on the retina, which is why you can sometimes see shadowy, dark spots.
They can also be symptomatic of a condition called posterior vitreous detachment, which is common in people over the age of 65. As you get older the vitreous humour changes and the central portion becomes more fluid, which causes the outer area (recognised as the cortex) to shrink and detach from the retina. Floaters are formed when the collagen starts to clump together.
It is common for the vitreous humour to become completely detached from the retina (this occurs in around 50% of people by the age of 50) but it will normally cause no problems. However, in some cases, the vitreous humour can start to pull on the retina, causing blood vessels within the retina to perforate and bleed into the retina. If the retina tears the blood which emerges into the vitreous humour can result in a sudden burst of floaters.
Symptoms of floaters
Symptoms of floaters include:
- Shadowy dots.
- Black spots.
- Shadowy lines and cob-web shapes.
- Noticing the floaters move as you shift your eyes.
- Floaters becoming more noticeable if you are looking at a blank background (for example, a white wall).
When should I see a doctor or an optometrist?
In the majority of cases floaters are not symptomatic of other eye problems. However, if you have floaters it is worth having an eye test as they can sometimes be early warning signs of conditions that affect your sight, including a detached retina. It is particularly important to see a doctor or an optometrist if the floaters get worse, you see sudden flashes of light or you experience impaired vision.
How are floaters treated?
In most cases floaters do not cause any harm and they do not require treatment. In most people the brain learns to ignore floaters and you will soon stop seeing them. However, if you do have floaters you may be advised to have regular eye examinations to check that your retina is healthy and stable. If floaters do not improve and they are affecting your vision, surgery may be required. The surgical procedure to treat floaters is called a vitrectomy and involves removing the vitreous humour and replacing it with saline solution. Surgery is rarely carried out as it carries risks for the eyes, and a vitrectomy may not always be available on the NHS.