One of the most helpful things for someone with achromatopsia is the right sunglasses. The essential thing is blocking light and regular sunglasses just won’t do. Blocking light requires both a very dark tint and the right frames that prevent light coming in around the edges.
For all I know on the topic, see:
There is a lot I don’t know, so feel free to share your experiences with me anonymously through my survey, and I’ll update my site with your input. (Thanks very much to all those who already filled it out! Responses are now online here.)
Also, don’t miss the 2009 Info Sheet on glasses for achromatopsia from UC Berkeley’s Dr. Gunilla Haegerstrom–Portnoy.