Glaucoma is a major cause of irreversible blindness worldwide, and it also causes substantial disability before patients become blind. This disorder is difficult to diagnose and manage. As vision loss due to glaucoma cannot be recovered, it is important to have regular eye exams that include measurements of your eye pressure so a diagnosis can be made in its early stages and treated appropriately.
What is glaucoma?
Glaucoma is a group of eye conditions where the optic nerve, which connects the eye to the brain, becomes damaged. It is usually caused by fluid building up in the front part of the eye, which increases pressure inside the eye. Glaucoma can lead to loss of vision if it is not diagnosed and treated early.
It can affect people of all ages but is most common in adults in their 70s and 80s. Glaucoma tends to run in families. In some people, scientists have identified genes related to high eye pressure and optic nerve damage.
The definition of glaucoma in adults has changed over the years due to changes in our understanding of how glaucoma affects the eye, technology available, and the reasons why a particular definition was constructed. A current clinical definition of glaucoma is: “A characteristic pattern of glaucomatous optic neuropathy (e.g. with narrowing of the neurorentinal rim) with corresponding visual field defects.” Glaucoma is a huge topic, and this article will be concentrating on open-angle disease in adults. Open-angle glaucoma is the most common form of the disease. There are other types.
What are some symptoms of glaucoma?
Glaucoma does not usually cause any symptoms in the early stages of the disorder. It tends to develop slowly over many years and affects the edges of your vision (peripheral vision) first.
For this reason, many people do not realise they have glaucoma, and it is often only picked up during a routine eye test.
If you do notice any symptoms, they might include blurred vision, or seeing rainbow-coloured circles around bright lights.
Both eyes are usually affected, although it may be worse in one eye.
Very occasionally, glaucoma can develop suddenly and cause:
• intense eye pain
• nausea and vomiting
• a red eye
• a headache
• tenderness around the eyes
If left untreated, glaucoma will eventually cause blindness. Even with treatment, about 15 percent of people with glaucoma become blind in at least one eye within 20 years.
When to see a doctor
Promptly go to an emergency room or an eye doctor’s (ophthalmologist’s) office if you experience some of the symptoms of acute angle-closure glaucoma, such as severe headache, eye pain and blurred vision.
Diagnosis
Your doctor will review your medical history and conduct a comprehensive eye examination. He or she may perform several tests, including:
• Measuring intraocular pressure (tonometry)
• Testing for optic nerve damage with a dilated eye examination and imaging tests
• Checking for areas of vision loss (visual field test)
• Measuring corneal thickness (pachymetry)
• Inspecting the drainage angle (gonioscopy)
Treatment
The damage caused by glaucoma cannot be reversed, but treatment and regular checkups can help slow or prevent vision loss, especially if you catch the disease in its early stages.
Glaucoma is treated by lowering your eye pressure (intraocular pressure). Depending on your situation, your options may include prescription eyedrops, oral medications, laser treatment, surgery, or a combination of any of these.
Prevention
These self-care steps can help you detect glaucoma in its early stages, which is important in preventing vision loss or slowing its progress.
• Get regular dilated eye examinations. Regular comprehensive eye exams can help detect glaucoma in its early stages, before significant damage occurs. If you are over 65 years, it is recommended to have a comprehensive eye exam every one to two years. If you are at risk of glaucoma, you will need more frequent screening. Ask your doctor to recommend the right screening schedule for you.
• Know your family’s eye health history. Glaucoma tends to run in families. If you are at increased risk, you may need more frequent screening.
• Exercise safely. Regular, moderate exercise may help prevent glaucoma by reducing eye pressure. Talk with your doctor about an appropriate exercise programme.
• Take prescribed eyedrops regularly. Glaucoma eyedrops can significantly reduce the risk that high eye pressure will progress to glaucoma. To be effective, eyedrops prescribed by your doctor need to be used regularly even if you have no symptoms.
• Wear eye protection. Serious eye injuries can lead to glaucoma. Wear eye protection when using power tools or playing high-speed racket sports in enclosed courts.
Conclusion
Glaucoma is one of the leading causes of blindness worldwide. People with glaucoma have optic nerve damage from fluid buildup in the eye. Left untreated, this eye pressure can permanently affect vision. In many cases there are few symptoms – therefore it is important to have regular eye examinations. Treatments — including eyedrops, laser treatments and surgeries — can slow down vision loss and save your sight.
Ask Your Doctor is a health education column and is not a substitute for medical advice from your physician. The reader should consult his or her physician for specific information concerning specific medical conditions. While all reasonable efforts have been made to ensure that all information presented is accurate, as research and development in the medical field are ongoing, it is possible that new findings may supersede some data presented.
Dr Brett Hodge is an Obstetrician/Gynaecologist and Family Doctor. Dr Hodge has a medical practice in The Johnson Building in The Valley (Tel: 264 4975828).
