The Phoenix opthalmologist who invented Frubi sunglasses for babies and kids did so because he was really concerned about the possible risks tiny eyes face from overexposure to sunlight. Apparently, baby lenses are far less resistant to UV and other wavelengths of light, and so he recommends sunglasses with a very high EPF [eye protection factor], say, 99.5 or above. But since the EPF scale only goes to 100, and since Frubis rate 99.5, why look anywhere else?
Frubis are soft neoprene, like Croakies, with safety plastic lenses. You'll want to use some serious SPF sunscreen on your kid, too, otherwise, he's gonna get the fiercest racoon eyes you've seen since that helicopter skiing trip in the Bugaboos. Frubi's biggest drawback is one shared with most sunglasses: wearing them often attracts attention. So out of respect for your child's clearly expressed desire for privacy, do him a huge favor and don't take any pictures while he's out Frubi'ing. Seriously, he'll thank you later.
Frubi sunglasses are around $15 somewhere [frubishades.com]