By Jancie Tai

Glaucoma is like a thief that sneaks up on you. Worldwide, about 70 million people have this eye disease and about half do not know they have it.

Glaucoma accounts for 40 per cent of blindness in Singapore.

It can occur when the fluid pressure within the eyeball is too high. This damages the optic nerve which carries visual impulses from the eye to the brain.

The reason for this pressure build-up is an imbalance between the production and drainage of fluid within the eyeball. One can have glaucoma yet be able to see well and be without symptoms in the initial stages.

This is because in one type of glaucoma called open angle glaucoma, peripheral vision is affected first.

One can still have very good central vision even though peripheral vision is being lost.

Dr Francis Oen, the director and senior consultant ophthalmologist at Singapore Eye & Vision clinic, said he has seen some middle-aged and elderly patients who manage so well with their central vision that they are still able to drive.

Their visual fields are sufficient to pass the driving requirements even though they may have lost their peripheral vision.

Effective management of glaucoma involves early detection and prevention of progression of the disease by medication, laser treatment or surgery.

Proper management is essential as there is no cure for glaucoma. Getting it properly diagnosed is not always that easy.

"It may take a few consultations as we no longer depend on high eye pressure to confirm glaucoma.

Many patients may have eye pressure that falls in the normal range and yet show typical signs of glaucoma," said Dr Oen.

For successful glaucoma management, get a complete eye examination that not only tests for eye pressure, but also includes an examination of the optic nerve and a visual field test.

Have a check-up once in two years, especially if you are above 45 and have a family history of glaucoma.

Take the prescribed medication too.

Compliance is essential to prevent progression of the disease.

Dr Oen noted that some patients did not take their medication regularly and, as a result, their condition worsened over time.

This article was first published in Mind Your Body, The Straits Times.