Dyslexia is an impairment in reading that can result from an abnormal developmental process. Although dyslexia is lifelong, individuals with dyslexia frequently respond successfully to timely and appropriate intervention. While many believe dyslexia has its core in a disruption of language processing, others believe that it may be a visual disturbance.  Dyslexics often complain that small letters appear to blur and move around when they are trying to read, as a result research is being done in the field of optometry to clarify whether there is a visual component.