The VCS Test - Visual Contrast Sensitivity
The online VCS Test is a measure of one of the neurologic functions of vision called contrast. In order to take this test, your corrected visual acuity must be better than 20:50.
There must be adequate illumination. We use a light meter to confirm 70 foot-lamberts or more. Light from both the illuminated computer screen and an overhead light is usually sufficient. The test is taken with one eye covered and one open at a distance of 18” from the computer screen. You will do the test first with the left eye and then with the right eye. You need to make sure the distance from the screen stays constant at 18”. Some people have found that cutting a string to an 18“ length helps keep the distance correct. Your score is recorded according to published criteria for VCS testing. It is a ”Pass/Fail,” though how well you do can be used to assess your improvement over time or worsening with re-exposure/repeat illness.
You need to know that the computer version of the VCS test is a screening test and is not used to diagnose any condition. If you are concerned about the possibility of a biotoxin associated illness you will need to be examined by a physician experienced in the field. We recommend your VCS testing results be validated for you by use of a hand held VCS test.