I picked this one up because, like the author, I too was diagnosed with a degenerative retinal disease at a relatively young age. While my prognosis is more positive than Kear's, (with treatment* I will retain the majority of my vision), I still felt I was able to connect with her. That being said, I don't think you need to have a disability, vision related or otherwise, to appreciate this book. The writing is honest and the author's reactions to her diagnosis are understandable, albeit at times questionable.
*treatment is the stuff of nightmares. Think "A Clockwork Orange" or that children's rhyme that starts "Cross my heart, hope to die..." On second thought, don't think about it at all. Forget I even mentioned it.