Software for the visually impaired

So out of curiosity, I did a google search to see how many companies provide software for the visually impaired and to my surprise, there was more than I thought. I found one company Software Express who appears to be out of the UK. It appears to be somewhat decent software and I think it is great that they have this software to assist the visually impaired.

However, how does this company market its products to those that are visually impaired? I would think that most of it comes from word of mouth, or from organizations that those that are visually impaired are registered with. Anyway, I would love to hear from anyone who markets tough or really niche market software to let me know how they do it.