Another reason for school difficulty is a learning disability. Learning disabilities are more than dyslexia, a language-based learning disability that frequently causes children to reverse letters or words. Learning problems affect reading, writing, speech, attention span, comprehension and social interaction, much more than an easily corrected refractive error. Vision is an important part of learning. Almost 80 percent of what a child learns throughout his educational career comes to him visually.
Visual memory is another part of visual perception.
This entails recognizing words that you have seen previously, and using the eyes and brain together to form a mental picture of the words you see. You also form a picture of a cat in your brain. Or, you laugh out loud after reading a funny passage because you can picture the events happening in your mind. Many professionals, including teachers, pediatricians and some eyecare practitioners, focus only on the first of the three parts of visual function - the state of the eyes, specifically refractive errors. If vision is defined as seeing a certain size letter on a chart at a specific distance, then many children will have perfect vision even if they must wear glasses or contact lenses.