I am visually impaired but confident enough on a keyboard to not have to stare at it and confident my posts are intelligible. It is in the reading of, not the writing of which is the issue with visually impaired people, old or not. Some past conventions are entrenched, such as not typing in all caps - I do find it difficult to read and more often than not just skip that message. Really there is no excuse for typing in all caps when font sizes can easily be changed or monitors allow those with impaired visual abilities to view the content. Our eyes are used to not reading all caps, books have trained us over the years - even books with larger print allow content to be read without reverting to all caps. When I see all caps I just skip by.