Kevin Carey

Objective: To outline a variety of tests to establish measurable visual acuity

• If there are recognized vision tests in your country, adhere to these as closely as possible, as they may have regulatory and social protection implications for the blind child. Eye health professionals use a variety of techniques; see vision screening and visual testing from Low Vision Online.
• If you are using any vision test do not use symbols which the child may not recognize, since these are vision, not reading, tests.
• The following procedures can be used in addition to, or replace, standard tests where these are not available.
• Moving Objects. Place children in different colored shirts at distances along a route to the right of the tested child, then drive a car from right to left at 10 MPH and ask the child at what point, using the colored shirts, he can see a car. Increase the speed and take further measurements. The conclusion should read: “The child can see a moving object at x miles per hour at y yards.” Repeat from left to right with a different colored car.
• Near Vision. The most important measurement is near vision, enabling most classroom skills. Allow the child to determine the distance between himself and the viewing screen. Use a fabric tape measure or rope/string.
• Ideally the test should be conducted on a personal computer or tablet where the size of print and objects can be changed and measured.
• The next best option is a pre-prepared video clip. See also Low Vision Online for methods to assess near vision.
• If you have to use television, ask questions of the child on various sizes of objects on the screen.
• In all cases the result should be: “The child sees objects of x size at y distance.”
• If a child has exaggerated head and neck movement, it is probably an indicator of narrow field vision; a visual field of 10 degrees or less qualifies as blindness in many countries.
• Never confuse testing vision with testing memory. Do not use the same set of objects in a test twice.
• Try to be as objective as you can, but remember this kind of testing is a precursor to clinical testing