Equal treatment is a fundamental purpose of the ADA. People with disabilities must not be treated in a different or inferior manner.

The Americans with Disabilities Act protects the rights of people who have a physical or mental impairment that substantially limits their ability to perform one or more major life activities, such as breathing, walking, reading, thinking, seeing, hearing, or working. 

It does not apply to people whose impairment is unsubstantial, such as someone who is slightly nearsighted or someone who is madly allergic to pollen. However, it does apply to people whose disability is substantial but can be moderated or mitigated, such as someone with diabetes that can normally Abe controlled with medication or someone who uses leg braces to walk, as well as to people who are temporarily substantially limited in their ability to perform a major life activity. The ADA also applies to people who have a record of having a substantial impairment – such as a person wither cancer that is in remission or are regarded as having such an impairment – such as a person who has scars from a severe burn.