Accessibility (Disability, not convinience related)

Is accessibility in regards to the disabled (Seeing, movement, etc) on the development radar?

I was made aware of these problems a while back, when a guy who had bad vision, contacted me because he was using my theme and had problems reading the chat, because I hardcoded the font size, and overwrote the font settings in the options.

I myself am not disabled, so I do neither have the necessary hardware (“50” monitor", eyetracker, …), nor the necessary software (screenreader, …), nor the necessary experience, to check if everything is scaling and/or accessible.

I think this is a fairly important topic, that shouldn’t be forgotten about.