Visual disabilities include blindness, color blindness, and low vision. In addition to making your application accessible to assistive applications, such as screen readers, you should also consider the following:
Although color can greatly enhance a user interface, make sure it is not the only source of information. A color blind user may not be able to distinguish between two objects that differ only in color.
Provide an audio option to all visual cues and feedback. Your application should make it easy to replace visual communication with audio communication.
Provide an option to present images and animated content in an alternate manner. If your application displays an image or animation, consider providing your own succinct descriptions of these elements so blind or low-vision users can benefit from the information they convey.