Glaucoma is the term used to describe a group of diseases that can damage the optic nerve and result in visual reduction and even blindness. With early detection, treatment and follow-up, damage should be minimised.
What is Glaucoma?
There are several different types of glaucoma, the most common being “open- angle” glaucoma.
Fluid from the front part of the eye can not drain away properly through the “filter” at the angle between the iris and the cornea.
This leads to an ever increasing pressure inside the eye which in turn leads to pressure on the optic nerve fibres which send visual messages to the brain. Peripheral or “side” vision is affected first then, when damage is more severe, central vision becomes affected. It is not painful, therefore you can be completely unaware it is happening. Once damage has occurred it cannot be reversed, only further dam- age can be minimised by regular control of the pressure. If you are over 40 and have a family member with glaucoma it is important to have your eyes examined once a year. Eye pressure can be measured by a puff of air onto your eye or using anaesthetic drops and gently pressing a special instrument onto the surface of the eye. It takes only seconds to do.
Monitoring and treatment of glaucoma
Optic nerve damage can be assessed by looking into the eye with an ophthalmoscope and by testing the visual fields with a special light and chart. This is done regularly to monitor the progress of the disease and so adjust treatment accordingly. Drops which reduce the pressure in the eye can be prescribed on a regular basis or sometimes an operation is done to improve matters. If you are prescribed drops you must never stop taking them unless your doctor advises you to do so. If surgery is required a small opening is made just under your eyelid to let fluid escape and thus lower the pressure inside the eye. This fluid forms a little “bleb” under the thin covering on top of the eye. The fluid then gradually gets absorbed back into the bloodstream. After surgery you may well need to use different drops for 4 - 8 weeks until the pressure is controlled. Occasionally, the operation needs to be repeated if the opening closes up.