Treatments

Glaucoma

Glaucoma is a set of common, silent, potentially blinding eye conditions. It occurs more commonly in those with a family history of glaucoma. The commonest type of glaucoma, chronic open angle glaucoma, progresses very slowly and many effective treatments are available to retard its progress. This is why it is important to check for the presence of glaucoma at least 3 yearly after age 40. Less commonly, acute angle closure glaucoma presents with sudden fogging of vision and pain. Early treatment of this type is usually very successful.

The aim of treatment is to arrest progressive visual loss because one cannot recover loss that has occured. Glaucoma has been likened to a mouse nibbling away at a block of cheese or to "rusting" of the vision.

Glaucoma causes loss of vision from the gradual and accumulating death of fibres of the optic nerve, the nerve of sight. The eye, which contains no bone or cartilage, maintains its shape by being inflated by a fluid pressure. That pressure must be sufficient to hold the shape of the eye but not so high as to prevent bloodflow into the eye to nourish its internal structures. In glaucoma, excessively high pressure over time causes fibre death at the optic nerve head which loses its full pink appearance and becomes flat, excavated and white. Consequently, the width of the field of vision of the eye is lost, leading ultimately to tunnel vision in many end stage glaucoma cases.

Testing for glaucoma thus includes, measurement of the intraocular pressure, examination of the appearance of the optic nerve at the back of the eye and computerised testing of the width and completeness of the field of vision.