Visual Fields: What you need to know about Visual fields

Visual Fields | orasisac.com
Visual Fields | orasisac.com

Visual Field Testing:

The space that is perceptible through the eyes is called Visual Field. The examination of Visual Fields is in effect a mapping of the area the eye can perceive when focused at a central point and at the same time the control of the eye’s sensitivity to various stimuli projected within a dome-shaped device.
Thereafter, the results of the test are evaluated by an ophthalmologist. Visual Fields are the most important examination for prevention, diagnosis and follow-up of Glaucoma Disease. The procedure lasts about 30 minutes.

Why is it important to have a Visual Field examination?

It is common that someone may assume that he possesses a normal peripheral vision, although it is not easy for someone to evaluate it subjectively. Examination of peripheral vision by simple means, for example when the doctor waves his hands in front of the patient standing opposite to him (confrontation test), is valuable only in severe defects of the visual field.

On the contrary, many serious conditions related to the peripheral vision can be detected in their early manifestation, before they lead to severe loss of vision, by using the Visual Field examination.

Such Neurological or Ophthalmological diseases that can be detected, prevented and diagnosed through the examination of Visual Fields include Glaucoma, Optic Neuropathies, Pituitary Adenomas, Brain Tumors, etc.

How do I know if I need a Visual Field examination?

Visual Fields – How do I know if I need a Visual Field examination? | orasisac.com
Visual Fields – How do I know if I need a Visual Field examination? | orasisac.com

Visual Fields are an important part of routine health care of the eyes for people that are in danger of vision loss from various diseases. Patients with the following conditions should be monitored regularly by their ophthalmologist, who will determine how often they need a Visual Field test:

  • Glaucoma
  • Multiple Sclerosis
  • Thyroid disease
  • Central Nervous system disorders (such as a tumor that can press on parts of the brain responsible for vision)
  • Stroke

Long term use of specific drugs (like Plaquenil, or hydroxychloroquine, which requires an annual check-up of Visual Field).

Patients with diabetes or elevated arterial blood pressure face a greater risk of developing blockage of blood vessels in the optic nerve and retina. Visual Field Tests may be needed to monitor the effects of these conditions on their vision. If your field of vision is limited, your ability to drive may be at risk.

Visual fields - Examination | orasisac.com
Visual fields – Examination | orasisac.com

How is the Visual Field examination performed?

To check for a suspicious eye problem or monitor the progression of an eye disease, your ophthalmologist will rely on more specific tests to measure how you see objects in your field of vision.

The automated static perimeter test is used for this purpose. The test helps to create a more detailed map of points you can or you cannot see.

To do this test, you will look at the center of an instrument in the shape of a bowl called Perimeter. The eye that is not examined will be covered. The prescription of your nearby glasses will be placed in front of the eye being tested to make sure that you see as best as possible. You will be asked to continue looking at a central target throughout the test. Small, dim lights will start to appear in different places throughout the dome and you will press a button every time you see a light.

The machine monitors which lights you did not see. You can open and close your eyelids normally during the examination. You can also stop the exam if you feel you need to take a break for a while.

Because you are looking straight ahead during the test, your doctor can understand what lights you are seeing outside of your central vision area. Because Glaucoma affects peripheral vision, this test helps show if there is vision loss outside of your central field of vision.

 

Relevant Links – Sources:

https://www.aao.org/eye-health/tips-prevention/visual-field-testing

https://eyewiki.aao.org/Slit_Lamp_Examination

https://www.aao.org/eye-health/ask-ophthalmologist-q/fundoscopy