Don't always ignore disturbances in your vision

Lubricating eye drops being used by golfer Tiger Woods in this picture, can help with eyelid twitching and dry eyes. — AP

Some visual disturbances are annoying but nothing to worry about.

Others, however, can be signs of a potentially serious condition requiring immediate medical attention.

How to tell the difference?

Falling into the merely annoying category are eye floaters, which are spots in your vision that drift about when you move your eyes.

Mostly caused when tiny strands of your vitreous (the gel-like fluid inside your eye) clump and cast shadows on your retina, they're usually a natural part of ageing, says the Good Vision Board of Trustees (KGS), an independent German information group.

Flickering vision is often caused by a low blood sugar level or migraine headache. Simply eating something or taking a migraine medication is usually all that's needed for relief.

Eyelid twitching is a sign of being overstrained, in which case relaxation and sleep are advisable. Lubricating eye drops can help as well.

Having the feeling you've got something in your eye, such as a grain of sand, is usually due to dry eyes. Sometimes called "office-eye syndrome," it mainly occurs by staring at a computer screen for too long and not blinking enough.

Wearing computer glasses will help relax your eyes, and eye drops or sprays containing hyaluronic acid (sodium hyaluronate) will provide additional lubrication.

To prevent dry eyes and eye strain during prolonged work at a computer, it's a good idea to take regular breaks, blink often and roll your eyes every once in a while.

A more worrisome visual disturbance is when straight lines, such as light poles, occasionally seem wavy, or letters in a book appear to bend.

This can be a sign of age-related degeneration of the macula, the central part of the retina. If the condition is detected early, doctors can prescribe medications to counter impaired vision.

Experiencing many eye floaters at once that move in the same direction, recurring flashes (bursts of light across your field of vision) or temporary vision loss are emergencies that require a medical examination. They could be a sign of incipient retinal detachment, a serious eye condition.

Seeing rainbow-coloured halos around lights, eye pain, blurred vision, nausea and vomiting are symptoms of glaucoma, which can lead to permanent vision loss if untreated.

And if you suddenly have double vision, a severe headache and perhaps even signs of paralysis, you should see a doctor immediately. The cause could be a stroke, cerebral haemorrhage or cerebral thrombosis. – dpa