What You Should Know About Visual Field Tests and a Comprehensive Eye Exam

Woman taking eye test

During Vision Health Month in May, the Canadian Association of Optometrists launched a monthly vision health education series. The series provides regular insights into important services that optometrists provide as part of comprehensive and follow-up (recall) eye examinations that are not always fully reimbursed by group vision care plans.

The important take away message from this series is that functional changes in the eye can be detected through specialized testing like a visual field test well before symptoms or structural changes start to happen. On the other hand, other machines like OCT may detect structural changes before functional changes occur–more on OCTs next time. Screening for serious eye diseases through regular testing, whether a visual field test or OCT allows for early diagnosis and intervention. This is critical in mitigating vision loss and avoiding higher medium-and long-term costs to plans in prescription drugs, assistive devices and in some cases long-term disability. While provincial plans typically provide reasonable coverage once a diagnosis is made, there is a gap in public coverage for tests that can lead to early diagnosis and intervention. With the information contained in this series, plan sponsors, advisors and insurers can consider how to amend their plans to fill the gaps that exist between private and public coverage.

A visual field test is part of a comprehensive examination and recall examinations when ongoing monitoring or treatment is required. The visual field test is used to identify parts of vision loss in the eye that the individual may not notice, and it will evaluate:

  • What the eye sees straight ahead as well as peripheral vision–that is, what the patient sees to the left, right, above and below without their eye moving; and

  • How sensitive the vision is in different parts of the visual field.
    The visual field test can also measure the amount of vision lost and the areas of the eye


Why is measuring visual field, peripheral vision, so important? Reductions in visual field can indicate glaucoma, a leading cause of blindness for Canadians. Early loss in peripheral vision from glaucoma is undetectable by the patient and can only be picked from a visual field test. The peripheral vision diminishes as the disease progresses and can ultimately lead to blindness, particularly if left undiagnosed or untreated. Results of visual field testing can also establish if someone meets/does not meet driving standards, identify pituitary gland tumors, neurological conditions, and determine visual function after a stroke or post trauma, for example, a car accident or sports injury.

The visual field test compares results to established standards for what is considered “normal”. These results help an Optometrist decide whether additional testing is required or if treatment is recommended. This is particularly important for those at risk for or who have a diagnosis of glaucoma. Glaucoma is a progressive disease and worsens over time. If results of the visual field test are outside the normal range, then the test may need to be taken again in a few weeks, months, or a year to determine whether the condition is progressing. If the patient is receiving treatment, then the test will help determine how well treatment is working.

The value of visual field tests in protecting the vision of plan members is supported by medical evidence. Unfortunately, there are gaps in group plan coverage that should be remedied to ensure plan members Don’t Lose Sight.

The Canadian Association of Optometrists (CAO) recommends that plan sponsors, insurers, and group benefit advisors review group vision care plans to ensure coverage for visual field and other diagnostic and monitoring tools are eligible for reimbursement, particularly during the initial testing and monitoring phase. Doing so will ensure that plan members and their dependents have access to the services of an optometrists to mitigate the incidence and impact of serious eye diseases like glaucoma and other health conditions that can affect vision.

CAO represents more than 80% of optometrists across Canada who are committed to the eye health of Canadians. If you require any assistance, have any questions, or would like to consult with the CAO on how to examine your vision care plan for gaps in care and help modernize it, please do not hesitate to reach out to us at info@opto.ca.

Click here to download the related PDF