These visual skill deficiencies can reflect in both performance deficits and behavioral adaptations. The more parents, teachers, and related professionals become aware of symptoms which typify these visual problems, the better we are able to identify those children who are at risk. It is important to differentiate the measure of sight from the complex process of vision. Sight is the simple response of the eyes to light and to the differences in brightness contrasts. It is the ability to identify, interpret and understand what is seen.
Vision is learned and constantly undergoes change and development.
Following are definitions of the primary physiological skills required to perform efficiently along with a checklist of symptoms which typify deficiencies in these visual skills. This skill involves the clearing of an image for identification. All judgements of spatial localization, depth perception and the accuracy of a single clear image depend upon this paired action of the eyes. With this skill comes more effective ability to make visual discrimination of size, shape, texture and location of objects. Classically, deficiencies in these skill areas reflect more in aspects of learning how to read.