When you create OER, there's an opportunity to make them accessible which shouldn't be missed. The guidelines and tools are out there to help you make your content accessible to everybody, irrespective of any reading / visual / motor impairment(s) or none.
The Universal Design for Learning (UDL) framework by CAST includes "a set of principles for curriculum development that gives all individuals equal opportunities to learn, including Students with Disabilities" (AHEAD, 2017).
Hilderley (2013) addresses structure, content, and appearance - simple changes like font, font size, colour, alignment, line spacing, as well as alternative text descriptions, meaningful tagging, and text-to-speech capability - with a helpful reference list (see Further resources).
See also:
Guidelines for web content accessibility 2.2 (draft) by the World Wide Web Consortium (W3C)'s Web Accessibility Initiative
Wikibooks- file format "openness" (revised 2018)
