Edward de Haan, a noted clinical vision researcher for the last 35 years, explains how the healthy brain deals with visual information and reveals how he learned to appreciate what it means to be visually impaired. Through discussions of fascinating case studies, he shows that visual deficits are individually unique. Some patients perceive the world without color, some see objects in a distorted manner, whilst others will claim that they can still see although they are demonstrably blind. The author details his experiences with these patients to demonstrate the manner in which patient work is a unique and vital part of discovering how the brain processes visual information. In doing so, Impaired Vision offers a review of the clinical symptoms related to visual impairment and highlights that the patient study method has not lost any of its relevance in our increasingly high-tech world.