A Clearer Picture on the Use and Types of Visual Field Exams

A Clearer Picture on the Use and Types of Visual Field Exams

Nov 01, 2020

Visual field testing refers to eye examinations done to detect any dysfunction in peripheral and central vision caused by medical conditions like brain tumours, glaucoma, pituitary disease, and stroke. The test uses degrees as a form of measurement, and the four quadrants from where it is centrally fixed include the temporal, inferior, superior, and nasal parts.

Because the brain and nervous system control separate parts of the visual field, specific patterns indicating vision loss are interpreted to pinpoint where a problem lies along your visual pathway

Abnormal results always mean that you have an undiagnosed medical problem or CNS issue. Examples ofpotential causes include diabetes, optic glioma, multiple sclerosis, macular degeneration, stroke, hyperthyroidism, hypertension, giant-cell arteritis and glaucoma.

You can receive visual field-testing services in North York, ON, at Yorkdale Eye centre.

Who Needs This Test and What Are Its Uses?

Should you visit a medical practitioner when you are unwell, and he/she suspects glaucoma, this is the first test he/she will schedule for you. This test helps doctors choose the right target for intraocular pressure and come up with a follow-up plan. Should you test positive for the disease, you’ll be required to come for more tests over time to see if the glaucoma is progressing or has gone into submission.

The following is a list showing the various employment of visual field exams:

  • Testing for factitious disorders or malingering behaviour
  • Detection of illnesses that affect optic nerves
  • Measuring the progression of retinal illnesses
  • Toxicity tests for certain medications that are known to affect a person’s central retina
  • Glaucoma and lid droop testing and screening

Types of Peripheral Vision Test

  1. Confrontation Eye Field Test

An eye doctor conducts this test by moving his/her hand inside and out of the patient’s visual field. He/she gives patients an occlude (a tool resembling large spoons) to obstruct one of their eyes and then asks them to make a sign when they can spot the practitioner’s hand. Although it’shard to measure this test’s accuracy, doctors use the results to gauge whether the patient needs more testing.

  1. Amsler Grid

This grid consists of simple square patterns with a point in the middle. Using one eye, an individual looks to see whether there are any areas on the grid that appear blurry, blank, dark, or distorted. If he/she sees any of the deficit mentioned, it tells the doctor that something is wrong. This test is done to detect issues with the central vision that is often linked to macular degeneration.

  1. Static-Automated Perimetry

During an automated perimetrytest, a unique computer program is used to test an individual’s visual field. One is required to take a seat and stare into a piece of dome-shaped equipment. Throughout this test, you will be instructed by a medical care provider to stare at the objects situated in the dome’s middle part and press a small button every time you see a ray of light.

Upon completion of the test, the computer generates a map depicting the patient’s visual field. This information is then used to diagnose the patient’s condition.

  1. Frequency-Doubling Perimetry

Compact machines are generally tasked to perform this test by displaying varying intensities of flickering images to the patient.

  1. Kinetic Perimetry

It is used to detect visual changes that may be as a result of optic neuritis or stroke.

What about the Test’s Reliability?

Most of these tests will take not take most of your time if you are a healthy patient. If not, expect it to take some time. Some limitations associated with this test are that they are quite challenging to do on younger children, persons with developmental delays, slowed reflexes, or mental disabilities. Since it’s a common occurrence for the first test to give inconclusive results, an experienced optometrist in North York, ON, will at least schedule the same test twice to improve the results’ reliability.

Should you pose abnormal test results, your physician may request further tests or send you to a specialist like an endocrinologist or a neurologist for additional exams and evaluation,including blood tests and brain imaging. In such cases, the patient’s blood is screened for hypertension, hyperthyroidism, and diabetes.

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