Comprehension often suffers as a result of excess effort required to make the print clear and single. Many children struggle unnecessarily, require excessive time to complete assignments, or simply avoid reading. Deficits in visual tracking may also interfere with classroom performance. Inadequate visual tracking causes jerky and inaccurate eye movements when reading, loss of place, poor copying skills, a need to use finger or marker to keep place, misaligning digits in columns of numbers, and difficulty with Scantron test answer sheets. Visual perceptual deficits should be suspected when a child confuses similar looking words, fails to recognize words previously learned, or fails to demonstrate adequate sight recognition.
Excessive reversals are also a common sign of vision perception disorder.
Since these deficits interfere with reading in the earliest stages of learning to read, they should be particularly suspect in the child whose reading problem began in the first grade. Visual perceptual evaluation tests the child's ability to make visual judgements, recognize and remember shapes and forms, see similarities and differences, and process visual information. Detection and diagnosis require a specialized evaluation that goes beyond the ability to read the eye chart. Such an evaluation is performed by optometrists who specialize in vision therapy. When these vision disorders are detected, they are usually treatable, often with significant gains in classroom performance.