VISION
Seeing two of a kind may be an indication of more serious problems
Eveline Gan, eveline@mediacorp.com.sg
More than meets the eye: Seeing double may point to a neurological problem.
It started with a headache and pain around her left eye. A week later, Mdm K began seeing double images.
"I lay in bed the whole day. I couldn't even watch
TV because I would see two of everything," said the 61-year-old homemaker.
She initially thought it was a side effect of her on-off headache and wanted to brush it off. Thankfully, her brother insisted on taking her to the hospital.
A scan revealed that the
muscles in her left eye had swelled up. Any delay in treatment would have led to more complications.
Certain benign eye conditions such as astigmatism - caused by an irregularly-shaped cornea - can cause you to see double images. So can extreme fatigue or overindulging in alcohol.
But if you start having double vision out of the blue, or if it keeps recurring, then you have every reason to worry.
According to Dr Wang Jenn Chyuan, senior consultant ophthalmologist and medical director of Nobel Eye and Vision Centre at Mt Alvernia Hospital, any visual problem should be taken seriously as it may be caused by more serious
medical conditions.
In fact, double vision, or
diplopia in medical lingo, is "almost always" one of the symptoms of a host of
neurological disorders, added Dr Nagaendran Kandiah, a consultant neurologist at
National Neuroscience Institute,
Singapore. They include
brain tumours, stroke, and
diseases affecting the
eye muscle and
nerves around the eyes.
Being able to see a single image with two eyes is a complex process that involves the brain, muscles and nerves.
Explaining how healthy eyes work, Dr Wang said: "When a person with
normal vision looks at an object, the brain and nerves coordinate the alignment of both eyes. This is so that the two images sent to the brain are perfectly superimposed on each other and he sees only one image."
A neurological or muscle problem can cause the eyes to be misaligned, so each has a different focus. When this happens, explained Dr Nagaendran, the brain will misinterpret the images to be in two different locations, causing you to see double.
A DOUBLE WHAMMY
And as if the discomfort of seeing double images isn't bad enough, patients also often experience headaches with their double vision, as in Mdm K's case.
Dr Nagaendran said that the pain may suggest that there is an
inflammation or aneurysm - a ballooning of the arteries - in the brain. Eye pain can also occur if the swollen arteries press on the nerves connected to the eye.
TUNING OUT
Sometimes, double vision which has been ignored for a long time may go away without any treatment. It may mean that your brain has learnt to "suppress" one of the images seen by one of the eyes, said Dr Wang.
"It's the body's way of preventing confusion when the mind perceives two different images."
But don't rejoice too soon.
Suppression of one of the images can result in lazy eye. And in the case of a more serious condition such as a
brain tumour or aneurysm, ignoring the problem can lead to blindness or death, Dr Wang warned.
In most cases, treating the underlying medical problem will help resolve the double vision.
"As long as there is no irreversible damage to the nerve or brainstem, most symptoms often go away, either partially or completely, in six to 12 weeks," added Dr Nagaendran.
For Mdm K, the prompt anti-inflammatory treatment she got after being diagnosed helped her to regain normal vision.
From TODAY, Health – Tuesday, 30-Jun-2009
In collaboration with Health Promotion Board
