The thoery in a low volume mask is it's easier to clear using less air and effort and because the frame is so close to your face you get less of a tunnel vision effect. I used a tri window mask years ago and it does allow a lot of light to enter and seems as if you see more. I would go to a large retailer and put them on and walk around noting your vision and how it makes you feel in general. Thast the most important thing after all
Bill
Bill
