This means sharpness of vision or the visual ability to resolve fine detail (usually measured by a Snellen chart). Visual acuity is expressed as a fraction. The top number refers to the distance you stand from the chart. This is usually 20 feet. The bottom number indicates the distance at which a person with normal […]

This term usually refers to a progressive decrease in visual acuity. However, it can refer to the sudden onset of substantial acuity decrease or total blindness.

The definition for most legal purposes in the United State is 20/200 vision with correction in the best eye, or field of vision less than 20 degrees.

An inability to recognize objects by sight.

A genetic disorder with both visual and hearing loss possibilities, Usher syndrome is characterized by hearing impairment as well as an eye disease called retinitis pigmentosa in which vision degenerates (gets worse) over time. Some people with Usher syndrome also have balance problems. Usher syndrome is the most common condition (aside from aging) that affects […]

The concept of user friendly or Universal Design, a term coined by the late Ronald Mace, is to make products, services and the built environment “aesthetic and usable to the greatest extent possible by everyone, regardless of their age, ability, or status in life.” This concept is used to describe architecture, interior and product design, […]

One method of determining user expectations is to look at commonly used products or services to see how they handle a similar situation. Your users will expect your product or service to behave the same way in similar circumstances. To decide which is the best option, you need to determine who will be using it, […]

These word processing programs allow the use of print characters on the screen while entering, editing and formatting text, and then use a single keystroke to translate the print to braille. The software applies rules for braille according to algorithms. The result of the translation is displayed on the screen in a variety of possible […]

Computer software that converts print documents into braille. The user does not need to understand braille to use the software but relies on the formatting rules built into the software to produce braille.

Notes written to explain visual graphic items such as photos, flow charts, graphs, floor plans, forms to complete and tables. These are used to help visually impaired readers understand what’s on the printed page being converted to braille or audio versions. Notes used in audio production are often called Reader’s Notes.