[Varyon]

An area-effect blood agent - which is probably what you're dealing with - has a lot more than just the eyes available to it. The nostrils, the ear canals, and the inner surface of the lips are all mucous membranes on the head, and you've got some down south as well (although clothing can help protect you there). Additionally, any cut, scrape, etc that hasn't at least scabbed over is a point of entry. So, yeah, if you aren't Sealed, a blood agent area of effect is going to get you, open eyes or not.

If it's something that only hits your eye, closing your eye and then holding your head down (so it doesn't drain and pool at the bottom of your eye socket, which will likely allow it to get past your eyelashes and into the mucous membranes around your eye; this also prevents it from draining down and into your mouth) may protect you. That's an extreme edge case, however - and at best, you're maybe looking at +1 to defense (if it was an attack you were trying to avoid; you could also have this be a small bonus to HT to resist), and if the +1 makes a difference you suffer One Eye, take a further penalty to Sight (most people will squint with their other eye if holding one closed, and even if not facing the ground isn't very conducive to seeing things in front of you) and DX (not being able to see well is going to make fighting harder), and foes can target your Skull from the front at only -5, until you're able to thoroughly wash your face. Not really worth the complication to implement, I feel.