Why do I have black dots in my vision?
Have you seen small black dots in front of your eyes? Many people have ‘floaters’, which are small irregularities in the gel inside the eye. You might be aware of threads that appear to float in front of your vision, or something that looks like small pieces of cobweb. These spots and threads can be semi-transparent or dark, and are called Floaters. Often you are unaware that you have floaters: if they have been there since birth your eye and brain learn to ignore them. If you move your eye to try to look at a floater it is likely to move away in the direction you move your eye. You might only see them if you are staring at a light coloured surface or at the sky during the day.
Most of the time, floaters are remnants from when the eye developed. If you have this sort of floater you may have been aware of them for many years. For other people, the number of floaters increase with age. Occasionally an increase in floaters can be a sign of problems inside the eye. Some people find floaters a nuisance if they are visible much of the time, but most people become used to them. They rarely cause problems with vision.
Why do Floaters occur?
Floaters are small dots in your vision. Some floaters are present from birth. Others occur as the gel in the eye, the vitreous humour, shrinks over the years. The gel separates into a watery fluid with wavy collagen fibrils which are seen as line-shaped floaters. Sometimes the gel shrinks enough to collapse away from the lining at the back of the eye, the retina. This is a normal occurance and is called a Posterior Vitreous Detachment or PVD. Once the gel has collapsed, some people see a large ring shaped floater. Occasionally some eye diseases that cause inflammation can increase the number of floaters in the eye.
Who is at risk of Floaters?
Floaters are more common in people who are quite short sighted. They may increase if you have had an eye operation, like cataract surgery, or other eye trauma.
I have flashing lights before my eyes – what are they?
Do you see flashes of light in front of your eyes for no obvious reason? This can be small sparkles or something like lightening or fireworks. Flashes occur when there is a pull on the retina, a layer of cells at the back of the eye that it vital for vision. This might happen as the gel inside the eye, the vitreous, becomes more liquid and collapses: a PVD. You may experience flashes occasionally, off and on over weeks or month. Flashes can also occur if you are hit in the eye.
Are flashing lights before the eyes related to migraine?
Flashing lights in front of the eye can be due to migraine. Some people with migraine experience an aura half an hour or so before the headache and nausea or vomiting starts. The aura can include shimmering or zigzag lines which may block part of your vision. Some people can experience the flashing lights without going on to have a headache. If you have flashing lights for a limited period of time which then pass off entirely these may be related to migraine. Talk to your GP if this is a new experience for you.
When might flashes and sudden increases in floaters be a problem?
A shrinking of vitreous gel and its subsequent collapse (suggests a PVD has occurred), along with flashes, (indicating that the retina has been pulled off by the collapsing gel), are important symptoms to note.
Usually these symptoms occur with no consequences, but occasionally a tear in the retina results from the shrinking and pulling away of the gel from the retina.
If untreated, a retinal tear can go on to become a full retinal detachment. Treatment for a retinal tear is more straightforward using laser or cryotherapy, but a retinal detachment usually requires surgery.
Detection of a retinal tear at the earliest opportunity is vital, to avoid progression to a retinal detachment, so if you notice flashes and or a sudden change in floaters, you should visit an optometrist straight away.
You will need dilating drops to get the best view of the retina, so must not drive to the appointment. At Colin Lee and Jenks opticians we would want to see you the same day, usually under an NHS scheme called community urgent eye services (CUES) provided your GP surgery is enrolled in the scheme.
Will the flashes and floaters stop?
Usually the flashes stop as soon as the gel has come away from the retina. The floaters will persist but we almost always learn to ignore them and stop noticing them altogether.
Further advice.
Even with a thorough dilated examination, it may be very difficult to detect a small tear, far in the periphery of the retina. Patients who have had symptoms of flashes and floaters should still be vigilant for six to eight weeks after the symptoms occur, even though they have had a dilated examination at the optometrists. If you notice any persistence of the flashes, shadows in the vision or missing vision, you should seek advice from your optometrist immediately or go straight to an Eye A&E such as New Cross, BMEC or Burton Queens hospital.