How long has he been partially-blind? I'm guessing not for very long, or it probably wouldn't even have occured to him that it would be an issue.

I've been blind in my right eye since it was removed, along with a cancerous tumor, at age two. It's never slowed me down, that I can tell anyway. I mountain-bike, bicycle-commute, road-bike, snowboard, motorcycle, etc. etc. It does present some issues, but he should be able to adjust to it, just like he's had to adjust to everything else.

Tell him to go for it and just be sure to pay extra-careful attention to the blind side. I tend to err on the side of caution when approaching intersections and do one extra head-check *just in case*.

FWIW I'm still not totally comfortable in a crowded pack during roadie training-rides. Another guy I ride with is also blind in one eye and has been riding and racing on the road much longer than I, he's helped me out with a few tips here and there. Mainly stuff that applies to pack-riding though (listen for passing riders on your blind side, watch shadows, etc.), and not commuting. I suspect my tentativeness in packs is due more to the fact that I've only been riding in groups on the road for 4 or 5 years (as opposed to mtn. biking for 15), than it is to vision impairment.

Of course if he lost his vision later in life it might be more of an issue. For me it's just always been that way, so it's not so much of an adjustment, as it is just the way things are...

-Trevor