What is Glaucoma?

Causes of Glaucoma

At the back of the eye is the retina, which converts light into electrical signals that are processed by the brain in order for us to see. The optic nerve is like a bundle of wires that carries this information from the eyes to the brain. Glaucoma results when these wires are damaged, often by excessive pressure buildup of fluid within the eyes. This pressure buildup can be due to excessive production of the fluid within the eyes, called aqueous humor, or by inadequate drainage or outflow of it. However, damage to the optic nerve can also result in cases of normal or even low intraocular pressure (that is, pressure within the eye) if other conditions such as low blood pressure are present. The optic nerve damage does not cause blur that can be corrected with glasses; instead it removes parts of the visual scene from being perceived. Peripheral vision is often affected first, and it is usually not noticed in the early stages. An eye examination is thus extremely important to pick up these early changes before they progress further. 

Diagnosing Glaucoma

During your eye examination, you will have your intraocular pressures tested. In addition, questions regarding your medical history will be asked, some of which are relevant to glaucoma. Your eye doctor will also look at your optic nerves, and their appearance can give a lot of information about whether glaucoma is present or not. If the intraocular pressure, medical history, or optic nerve appearance were suspicious, you would be asked to return to the clinic for several follow up appointments. During these visits, additional tests would be performed, like testing your peripheral vision, looking at the drainage system of your eyes with special lenses, measuring the optic nerves with instruments, and others. At this point, you may simply be followed more closely over a long period of time to catch any changes to the optic nerves. Alternatively, your eye doctor may decide that you do indeed have glaucoma and initiate treatment. 

While glaucoma is most commonly a slowly progressive disease, it may sometimes be the result of a spike in intraocular pressure due to obstructed outflow of aqueous humor. In these cases, the eye will be painful and red with hazy vision. This is an ocular emergency and urgent eye care should be sought to lower the pressure as quickly as possible. 

Glaucoma Treatment Options

Glaucoma cannot be cured and once vision loss occurs, it cannot be regained. Optic nerve damage and vision loss can only be slowed so that you maintain functional vision throughout your life. Lowering the intraocular pressure is the only method of treating glaucoma that is currently used. This can be done by eye drop medications that either reduce aqueous humour production or increase its outflow from the eyes. Laser procedures can also be done to increase drainage. If the intraocular pressure does not decrease enough or the optic nerve damage continues to progress, more advanced treatments include surgery to increase outflow and are done by glaucoma specialists.