I agree for the most part with Alexischristina.
However, I own a mare that is, at best, 85% blind (she's totally blind in one eye and mostly blind in the other) and she is no spookier than a "normal" horse. Actually, I think it's probably safe to say she's significantly less spooky than the average horse. She also stumbles a whole lot more than the average horse [and her feet are correctly done]. She's also seriously unbalanced at the canter and I generally only ask her to canter on light uphill grades because of that [however, she is 28 and I'm not confident working on her with her canter so some of it might be musculature, but even when she was younger+in work 5 days a week and cantering often, she was still scary to canter].
With my mare, her only "tell" that she's blind is really that she's really really nervous in a new pasture until she "maps" it out in her head. Literally, that is the only thing.
She's also a bit more touchy-feely tan the average horse and she does things a bit differently than the average horse (instead of walking in a circle to turn around in her stall, she'll turn on her haunches - stuff like that), however, those could certainly be Lacey-quirks and have nothing to do with her eyesight.
I've owned her for 5 years and it was only a yer ago that I found out she was blind. I had been around her on a daily basis for FOUR years before I even had any clue!! Of course, knowing what I now know does explain a lot...but really, she's so good at not showing it that I think I might never have found out if her eyes hadn't freaked out last spring.
I even had a vet check her eyes the year before because I always felt like something was "different" about her vision, but the check returned "inconclusive"....and she was at least 50% blind at the time [also, her eyes look like normal horse eyes - no stereotypical cloudiness].
Anyway, go with your gut. If your gut is eating at you about his eyes, get them thoroughly checked out. If the vet finds anything unusual, do research, find out what you're dealing with.
Personally, I love my blind horse. She is so much more fun than every seeing horse I've ever been around. Sure, it does take more work and it's seriously disconcerting to go back to a sighted horse and NOT have to cue the horse for varying ground condition, etc, but it is so worth it. The bond is incredible.
For what it's worth, after my mare passes, my next horse will be vision impaired as well. It's just that incredible. :)
ETA, here's a video of her running...you would never have any idea she can't see worth beans! Blindness comes in all forms, I guess. Haha