Glaucoma

Jump to: Symptoms | Diagnosis | Treatments | Clinical Trials | Research and Health Policy | Resources

Overview

Glaucoma affects more than 728,000 Canadians and takes the form of a number of related disease types. The most common types are open-angle, which is more prevalent and can go unnoticed due to a lack of early symptoms, and angle-closure, which can be painful with a sudden onset. In both cases, the eye’s drainage canals are blocked, leading to a build-up of aqueous humour fluid and increased intraocular pressure (IOP) that damages the optic nerve.

The cellular interactions that make sight possible occur within the retina, which is composed of light-sensitive tissue, but it is the optic nerve that sends the retina’s visual information to the brain, where it is translated as sight. There is no cure for glaucoma, but early detection and treatment can help prevent damage to the optic nerve and, as a result, save vision. Anyone can develop glaucoma but there are several different factors that can increase your risk of developing the disease, including high intraocular pressure (fluid pressure inside the eye); high blood pressure; a family history of glaucoma; corneal thickness, which affects eye pressure readings; being over the age of 40; previous eye injuries; long-term use of steroids; African, Asian, or Hispanic ancestry; nearsightedness; and diabetes.

Symptoms

Glaucoma can develop in one or both eyes, and in most forms of the disease there are no early symptoms that can be self-detected. It is essential to have regular eye exams so that your doctor can conduct the appropriate tests that will detect glaucoma and save your vision. If you experience any of these symptoms, please visit your ophthalmologist:

• Loss of peripheral (side) vision
• Halos around lights
• Eye pain and/or redness
• Blurred or decreased vision
• Eye pain

Diagnosis

Your ophthalmologist is able to conduct a number of different tests and offer a more specific diagnosis, including, visual acuity tests to assess your ability to see from different distances; visual field tests to measure your peripheral vision; dilated eye exams; ocular tonometry to measure the intraocular pressure inside your eye; pachymetry to measure.

Existing treatments

Currently, there is no cure for glaucoma, but there are treatment options that are designed to lower the build-up of fluid in the eye that can lead to optic nerve damage. Some of the main categories of treatment types are below; their appropriateness depends on the type and stage of the disease. As always, be sure to discuss treatment options with your ophthalmologist.

• Drug therapy: Eye drops and pills are the most common early treatment for glaucoma, and are capable of lowering eye pressure when taken regularly. Beta-blockers are used to decrease the amount of fluid in the eye; prostaglandin analogues and prostamides are used to increase the outflow of fluid from the eye; alpha-agonists and carbonic anhydrase inhibitors (CAIs) are both used to decrease the eye’s production of fluid. When prescribed, the regular use of these medicines is very important.
• Laser surgery: Various forms of laser surgery have been shown to have beneficial effects, and can often function as a middle ground between drug therapy and MIGS (least invasive, see below for MIGS) and conventional surgery (most invasive). Trabeculoplastyis the most common procedure, characterized by the use of a laser to open the trabecular meshwork of the eye, located at the base of the cornea, in order to improve drainage. Other approaches create openings in the iris, or remove parts of the ciliary body, which is responsible for producing fluid.
• Conventional surgery: As with trabeculoplasty, more conventional surgical techniques—usually categorized as trabeculectomy—can be used to create new openings for fluid to leave the eye. A drainage hole or “flap” is created to facilitate the expulsion of fluid from the eye through the space between the sclera (the outer, protective layer of the eye) and the conjunctiva, the thin membrane that sits on top of the sclera. Since these techniques can lead to more severe side-effects, including worsened vision, they are typically a last resort in the event that less invasive approaches are ineffective.
• Minimally invasive glaucoma surgeries (MIGS): MIGS are a group of devices and procedures that aim to lower interocular pressure by either improving fluid movement through the eye or reducing fluid production. Recovery from these surgeries is usually much quicker than from traditional surgeries.
  • Microtrabeculectomy involves inserting tiny tubes into the eye to help drain extra fluid. The XEN Gel Stent is one brand name for this type of procedure.
  • Trabecular surgery may be useful for early stages of glaucoma. It decreases eye pressure moderately, using small incisions into the trabecular meshwork. The iStent is one type of trabecular device.
  • Suprachoroidal shunts connect the front of the eye to the back of the eye. This tube helps redirect fluid drainage to the back of the eye. These types of devices are currently in development.

MIGS are a new set of procedures that are widely used throughout Canada. Many show a lot of promise in treating certain types of glaucoma, including some types where traditional surgery would normally not be a good option. The current evidence does not always show that MIGS are better than traditional treatment options.

Some MIGS approaches are covered by provincial health insurance programs in Alberta and Québec. In other provinces, patients may be able to receive MIGS but would have to cover the cost themselves or through private insurance.

Clinical trials

Clinical trials are essential to the scientific process of developing new treatments: they test the viability and safety of experimental drugs and techniques, called “interventions,” on human beings. While there is no guarantee that enrolling in a clinical trial will provide any medical benefit, some patients do experience positive results after receiving experimental therapy.

READ OUR CLINICAL TRIALS GUIDE

The website clinicaltrials.gov is a centralized database of clinical trials that are offered globally. But as the disclaimer on the site’s home page states, there is no guarantee that a listed trial has been evaluated or approved—the National Institutes of Health runs the site but does not vet its content. This means that there could be bogus or dangerous trials listed that are preying on patients. It is essential that you discuss a clinical trial with your ophthalmologist before enrolling, and that you pay close attention to enrollment criteria.

If you are interested in exploring what is available on the site you can click on the button below, which will take you to clinicaltrials.gov and initiate a search for trials relevant to patients living with glaucoma.

CLINICAL TRIALS FOR GLAUCOMA

Research Developments and Health Policy

Fighting Blindness Canada is committed to advancing the most promising sight-saving research, and has invested over $40 million into cutting-edge science and education since the organization was founded. Recognizing that science is tied to policy frameworks, FBC is also actively involved in health policy activities across Canada. Below is a list of some recent developments in research and policy related to glaucoma:

• Optic nerve regeneration: Though still in the early stages of experimentation and development, work is being done to develop an approach to reversing optic nerve damage caused by glaucoma. Usually taking the form of cell-based interventions—using cells to regenerate tissue, including stem cells—or in blocking molecules that inhibit regeneration, there have been clinical trials to test the efficacy of these approaches and research continues to move forward. Fighting Blindness Canada will continue to monitor progress in this area.

RESOURCES

Fighting Blindness Canada has developed additional resources that can be helpful in plotting an optimal path through vision care. Below is a link to our must-read resources, where you will find information on genetic testing, clinical trials, stem cell research, and more as well as a link to View Point (FBC’s virtual educational events).

MUST-READ RESOURCES
VIEW POINT: VIRTUAL EDUCATIONAL SERIES

Health Information Line

Do you have questions about your eye health or information shared on this page? Our Health Information Line is here to support you. For resources on how to monitor your risk to prevent sight loss, check out the following resources:

• Glaucoma tip sheet ENGLISH | FRANÇAIS
• What you need to know about glaucoma with Dr. Marianne Edwards

The below video provides a basic summary of glaucoma:

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Updated on May 12, 2021.