Keeping your eyes open underwater can take some getting used to.
In the pool, during the exercise, it's pretty easy to keep 'em shut. In that nice controlled environment, where you know how deep you are, and where your mask is, and that there's help right next to you, etc.
... and that's kinda the point. Scuba instruction at the introductory level is an iterative process. When you first start dealing with a mask-off, it's tough enough to just focus on maintaining a rythmic breathing pattern ... so you don't lose your buoyancy control. Closing the eyes often helps that process. At some point you can try to open them ... but intentionally inflicting chlorine burns on someone isn't a recommended way to get them to concentrate on what they're supposed to be learning.
This is a recreational activity ... not boot camp.
On a dive, with just a buddy, say you lose your mask. What now? You close your eyes. Your buddy doesn't notice and continues away. You're 90ft down. In complete darkness. Pretty helpless.
OK ... my take on this is that you've made several bad decisions before you ever got to that point ... the biggest being at 90 feet with someone you can't trust to be a proper dive buddy. But at that point, you open your eyes.
By the time you've gotten adequate experience to be at 90 feet, you'd better have surpassed many of the skills you learned in OW ... basic mask clearing being one of them. You shouldn't just get certified and go that deep based on what you learned in OW.
So the answer to "now what" is don't put yourself in that situation in the first place. After certification, practice your skills until they become almost as automatic as walking. Improve on them. Work on not just being a good dive buddy, but being discerning about who you choose to buddy up with ... THEN you might be ready to go to 90 feet.
But that wasn't the OP's question ... he's asking about what happens during the OW class. The answer is that it should be a progression ... learn to crawl, then try walking. Learn to walk, then try running. Learning to dive is no different.
Eyes open you can a) find and alert your buddy the dive is over (if no spare) b) perhaps catch your mask before it is gone c) possibly have a safer ascent.
... or choose a buddy who is alert enough to the situation to assist you ... that's why we dive with buddies in the first place. If you have to assume your buddy won't be there for you, then there's no point in diving with that person.
If you have contacts why not buy the prescription mask??
Lenses run anywhere from $160 to $240 ... depending on prescriptions strength and whether you need bi/trifocals.
Chlorine in the pool, salt in the ocean, silt in the lake. Kinda goes with the territory that the eyes are going to get a little irritated. May as well get used to it so it can be better dealt with at depth I'd say.
As a practical matter, mask clearing is one of the first skills taught in confined water. Get someone with burning eyes for the next two hours, and you've just reduced their capacity to concentrate on everything else you're there to teach them.
If you ask me they should take the mask and toss it ten feet away and have the trainee recover it to get used to seeing underwater without the mask. It's not hard, and I would think it to be kinda important.
That's a skill that used to be taught. When I did my OW class, we had to toss our mask and snorkel into the deep end of the pool, jump in and retrieve them, and clear the snorkel before lifting our face out of the water. But that was one of the last exercises of class ... in a class that involved 16 hours of pool time, where we had plenty of time to practice.
I'll agree that learning how to remove and replace your mask with eyes open is a useful skill ... where I'll disagree is that it's something that's useful in today's OW training progression. In many cases, it can do more harm than good.
... Bob (Grateful Diver)
