Visual Disabilities
Introduction

Something to Think About...

a close-up of an eyeYou mean I have a visual disability? Whenever I ask a large group of people whether or not they have a visual disability, very few of them answer that they do. Then I ask whether or not anyone uses any assistive technology to overcome their visual disability. Most people are unsure what I mean. Invariably, though, as I look out across the group, I see many of them, often a majority, using an assistive technology for their vision at that very moment.

"How many of you have perfect vision?" I ask. At this point, at least a couple of people catch on to what I am about to say. A voice in the audience says, "I wear glasses," "Yes," I say. "You wear glasses, and glasses are...?" "An assistive technology!" says someone in the audience, and that is exactly what they are.

eyeglassesWe are all so accustomed to seeing people wear glasses or contact lenses that we do not think of poor vision as a disability. Scientists and inventors have developed corrective lenses to compensate for the deformities in the shape of our eyes, affording us the possibility of seeing with perfect, though somewhat artificial, vision. Many of us have natural vision so flawed that there is no question we would have a disability were it not for our glasses. Bad eyesight is so common, and it is so easy to correct with glasses, that we often forget how different our lives would be without this incredible technological device.

Others of us have visual disabilities that are not so easily corrected, nor so easily forgotten. Some of us have no vision at all. Total lack of vision represents the extreme end of the scale of a condition that we call blindness. As it turns out, most people who are considered "legally blind" do have some vision. Legal blindness is commonly defined as a condition in which the best corrected visual acuity is 20/200, or less, or the person's visual field is 20 degrees or less. Despite the lack of visual acuity, people who are blind have an amazing array of assistive technologies available to them which help compensate for their lack of vision. We'll take a closer look at some of these technologies. magnifying glass

Another category of visual disability, low vision, is a common condition among the elderly, but younger individuals may also have this disability, whether due to genetics, traumatic injuries, or illnesses.

The last big category of visual disability is color-blindness, though it is probably an overstatement to call color-blindness a disability, since the conditions under which color-blindness is a true limitation are few. Still it is helpful to be aware of color-blindness when designing web content, as we will soon "see."