Eye Can Learn has great information and resources for parents who are wondering if a child's reading problems are related to vision issues.
This is my original post and the following comments relate to this post. However Eye Can Learn has recently updated their site. The following links no longer work.
Have a child try out these activities. The child should name the number before the next number appears. There are three speeds for practice.
Slow - Click here for practice.
Medium - Click here for practice.
Fast - Click here for practice.