Glaucoma Detailed Information

Glaucoma is not one disorder but a range of conditions in which the pressure inside the eye becomes too high. Glaucoma leads to blindness by damaging the optic nerve. The optic nerve is a bundle of more than 1 million nerve fibers. It connects the retina to the brain. (See diagram below.) The retina is the light-sensitive tissue at the back of the eye. A healthy optic nerve is necessary for good vision. Worldwide, glaucoma is the leading cause of irreversible blindness. It is a leading cause of blindness in the United States. Over 300,000 Australians have glaucoma.

As our population becomes older, the proportion of glaucoma patients is increasing. People at risk should get eye exams at least every two years. They include people over age 60, especially Mexican Americans and People with a family history of glaucoma There are many types of glaucoma. The most common is chronic glaucoma in which the aqueous fluid can get to the drainage channels (open angle) but they slowly become blocked over many years. The eye pressure rises very slowly and there is no pain to show there is a problem, but the field of vision gradually becomes impaired. Acute glaucoma is much less common in western countries.

This happens when there is a sudden and more complete blockage to the flow of aqueous fluid to the eye. This is because a narrow “angle” closes to prevent fluid ever getting to the drainage channels. This can be quite painful and will cause permanent damage to your sight if not treated promptly. Secondary and developmental glaucoma are two other main types of glaucoma. When a rise in eye pressure is caused by another eye condition this is called secondary glaucoma. There is also a rare but potentially serious condition in babies called developmental or congenital glaucoma which is caused by malformation in the eye.

Congenital glaucoma is very rare for children to be born with glaucoma but it is a recognised condition. There is a tendency for this to run in families, although it may occur in children with no family history of glaucoma at all. Early treatment can help protect your eyes against vision loss. Treatments usually include prescription eyedrops and/or surgery. Eyedrops are the most common form of treatment and must be used regularly. In some cases pills are prescribed. The drops can be varied to best suit the patient and the type of glaucoma. Laser (laser trabeculoplasty) is performed when eye drops do not stop deterioration in the field of vision.

In many cases eye drops will need to be continued after laser. Laser does not require a hospital stay. Surgery (trabeculectomy)is performed usually after eye drops and laser have failed to control the eye pressure. A new channel for the fluid to leave the eye is created. Carbonic anhydrase inhibitors like dorzolamide (Trusopt), brinzolamide (Azopt), acetazolamide (Diamox) lower secretion of aqueous humor by inhibiting carbonic anhydrase in the ciliary body. Physostigmine is also used to treat glaucoma and delayed gastric emptying.