... and the problem I had is that they were far from my nose (a large volume mask) forcing me to stare straight ahead to see. The side windows were then rendered less than useful. Still, back then I didn't wear contacts so it was the only way to see. It may be much less of a problem with low volume masks.
Now that I'm getting back into diving after a long absence I noticed the perscription was old, so I started to look around at alternatives. When looking for a place to grind lenses I stumbled across the Hydo Optix web site and was intrigued. I read the entire site and it made quite a bit of sense to me. Basic optical physics. As I am -4.75 and -5.75, the mask would actually leave me in far better shape if I lost a contact under water (you need to be -4.5 due to the concave lens formed by the water against the eye domes). A big reason I went from glasses was improved peripheral vision, and the mask looks to do the same for me under water. Unfortunately they aren't shipping just yet and my Bonaire trip is coming up at Thanksgiving. I'm on the "Urgent" list and there's a fair chance it will show before I board the plane. I will post a review of it should I get it in time.
I bought a normal mask with side windows and wore it with contacts in the pool for an equipment check and a course in "Underwater Basket Weaving" (yes, it's an SSI specialty course - and no, it's not a blowoff. It's really a bouancy/skills class and the basket weaving is used as a task to get your mind on something else so your normal breathing pattern will manifest). I found it nice to be able to see every thing without the extra distortion of looking out the edge of a thick lens. The class is where I really noticed tunnel vision. There I am working away on my basket when I get bonked upside the head by a leg drifting next to me. On land I would have seen it well before then, but uw I had to keep turning my head to watch out for the crowd. You don't really notice the tunnel vision because the magnification fills in the picture. Without the black edges you really don't get the full clue. So one of things I consider the mask for is the added situational awareness. It's something I've learned in my flying, and it applies uw as well. I figure it would be much easier to keep track of my buddy if I can see him at all times and not just when I turn to look.
I have toric lenses and have never had a problem with orientation. Your eye doctor will make sure the fit is correct for you. I started with hard lenses but couldn't tolerate them. When I was switched to soft, I couldn't tell they were in except for the fact that I can see. I wouldn't go back to glasses.
