Training & Videos

We’ll be working in pairs and will be screening a large number of children. The tests are simple to perform, but to do them effectively and efficiently it takes practice and experience. Following is a summary of the Sheridan Gardner and Stereo Fly tests.

Sheridan Gardner - Visual Acuity Test (CLICK HERE TO WATCH!)

  1. Introduce yourself to the child and explain what you’re going to do. Don’t use the words ‘test’ or ‘exam’. Cooperation of the children is paramount, so treat it like a game, and the kids will have a lot more fun.
  2. Describe how the SG works. Explain that you’re going to stand at the other end of the room, and that you’re going to ask them to point to the letter that they see. Explain that you will examine each eye independently. (You should use a folded piece of paper to occlude the other eye. Sometimes the child will want to use his or her hand. This is okay, but make sure that the child does not put pressure on the eye. Also, ensure that the kids don’t cheat by peeking!) If the child wears glasses, perform all tests with his or her glasses on.
  3. Choose a card other than the first (60) and have the child point to the letter, to ensure that child understands the instructions.
  4. One med student should sit with the child, and the other (the card flipper) should sit exactly 6 meters (20ft) away.
  5. Start with the first card (the O, 60). This ensures that the child understands the instructions and helps to build confidence.
  6. Work your way through the cards, reinforcing the child after every answer. Don’t correct the child. It doesn’t matter if the answer is right or wrong, as long as they’re trying to identify the letter. Stop when the child cannot identify the letters at a particular level. (The level is written on the back of each card. There are multiple cards for each level starting at 18.) Write down (for each eye) the last level at which the child can correctly identify the letters.
  7. Adjust for each child! If the kid is reading the answers easily and seems to be getting bored, it’s okay to skip cards until you get to the smaller optotypes. Pay attention to how the child answers to see if they’re guessing. Be extra careful to make sure that they don’t cheat (by uncovering the other eye). Also, make sure that they don’t put pressure on the other eye when they occlude it (since it will make their vision blurry when they open the eye).


  1. Put the glasses on the child over any glasses they’re already wearing. Be extra careful because the glasses are very delicate and very expensive.
  2. Open the book and position it in front of the child, at a normal reading distance, making sure that the book is facing them (not at an angle) and that there is no glare from overhead lights.
  3. Watch for the response when the child sees the fly. Ask the child to pinch the wings of the fly between his or her finger and thumb.
  4. Ask the child to point to the animal in each line that is “sticking out.” The correct answers are A) Cat, B) Rabbit, and C) Monkey. Try to keep the child from touching the panel so that they don’t smudge it.

Data Sheet

  1. Record the age and sex of each child. Record the name if you can, or if you have a class list, you can just write the # for each student (to avoid having to copy the name).
  2. Ask the student if they’ve ever been to a doctor to look at their eyes. Also ask if they’ve ever worn glasses (Y = yes, N = no, P = previously wore glasses, does not anymore).
  3. Inquire if the student has ever worn a patch (a treatment for amblyopia). Be sure to ask why the student wore a patch…we’re looking for children who have been previously treated for amblyopia, not kids who were pirates for Halloween.
  4. In the Left Eye and Right Eye columns, write the number of the last level the child could read. For perfect vision, this would be 6.
  5. Under Fly, A, B, and C, put a check mark if the child could pinch the wings of the fly or could identify the animal that was sticking out.
  6. For any of these tests, put NC if the student was non-compliant or could not follow the instructions. If there is a language barrier, write it in the comments.

Most importantly…Have fun!