Most of us were given two eyes. When they work together we get good stereopsis or depth perception. This means that even small differences in depth down to 40s of arc can be detected. We are better at judging movement and timing eye hand coordination. This allowed us to be successful hunter gatherers.
Fine motor control, bilateral skills and good balance also go with the eye skills. When we are told that we can see letters on the test chart that is a good start, however we need to be able to do more.
With younger children I use a lot of play based activities with red green therapy to increase their awareness of using both eyes. As this improves, work needs to be done to allow the eyes to team together. Success depends on your motivation and the stubbornness of the visual system to be trained.
If you have a particular problem to discuss, please email me. Assessment is usually an hour. A small child will have 30-40 minutes of play based assessment.