Birdstrike and eye protection.
Wear spectacles. If you're young enough not to need them yet, wear sunglasses.
A fellow-club-member and PPL was in the left seat of our PA28 when it suffered a forced landing following engine failure. The windscreen on his side 'failed' (i.e. broke into pieces) and he got multiple cuts to his face. One of his glasses lenses was cracked by a piece of flying plastic, but his eyes remained undamaged. He reckoned that without eye protection, he'd certainly have had eye injuries, possibly been blinded.
Light aircraft windscreens, unlike large PT aircraft, aren't certificated against any birdstrike criteria.
On the subject of spectacles...
If you're aged 40+ and have perviously benefited from having eyesight good enough not to need glasses for correcting distance vision, the chances are that you're going to need them soon to be able to read the map, instruments etc. For heaven's sake don't buy a cheap pair of reading glasses, 'cos you'll not be able to wear them to see out. I flew with a student the other day who was trying to do this, constantly putting them on and taking them off around his headest. He had them on some 'idiot reins' around his neck. Get yourself some prescription bifocals or better yet varifocals that you can wear all the time whilst flying. Badger your optician into getting your prescription suitable for flying. Don't go for half-moons, either, they're nerly as bad. I sat next to someone the other day wearing some, he was like a nodding dog trying to see either over or through them.
Cheers,
TheOddOne