I was very interested in the Sea Vision product. Unfortunately there is no dealer in the region and I have a difficult fit. I contacted them and there is no such thing as a loaner or other means of checking the fit short of buying the mask. All in all pretty lame for a company that is offering online sales. Still it looks like a great product.
I wear progressive eyeglass lenses with moderate astigmatism correction.
The first thing I learned with some research is that with cylindrical (astigmatism) correction greater than 1 I really don't belong behind common diopter lenses, they should include the cylinder correction so that ruled out off the shelf pop-ins.
The next thing goes back to my previous bifocal overlay mask. Diving mainly in Maine we generally do not have what you would call magnificent visibility. While being able to keep track of a buddy in the 10-15 foot range is typical the prime visuals are closer and tend to be on the bottom. With the bifocal mask I tended to swim low, following the bottom like an anteater, nose down. In a moment of error I happened to loose this mask (another story) When I started diving my non prescription mask I had a sudden surprise. All of a sudden I was swimming 2-3 feet from the bottom and getting a more panoramic view! What I realized is that with the bifocal mask and the tendency to be looking down I was being sucked into the near vision portion of the lenses and adjusting my physical distance for some intense close-up vision. While my eye's would be a little weary after 2 dives I could still read all of my instruments OK so I finished the summer diving non prescription while I sorted this experience out. On top of that with the bifocal mask instrument positioning was a little tedious for the best vision.
The next thing I learned about was my diopters. It turns out that I am an oddball (what's new!) Both my near and far corrections are positives. Most folks have a negative diopter for distance correction and a positive for near. Due to this fact a single focal lens for one sort of viewing will ruin the other. In my case my prescribed distance correction gets me about 1/2 way to perfect near correction. Since I can already read my instruments uncorrected this is just fine. As an aside, nearly all of the off the shelf pop-in prescription lenses are negative diopters. There are some brands that offer a few positives but this will really limit your mask choices.
So now I have a brand new single focal mask with prescription overlays that is waiting for it's first dive. In topside tests it provides great far vision (nicer than my street glasses). The near vision tests were right where I expected and will be fine.
I hope this journey is helpful.
Pete
I wear progressive eyeglass lenses with moderate astigmatism correction.
The first thing I learned with some research is that with cylindrical (astigmatism) correction greater than 1 I really don't belong behind common diopter lenses, they should include the cylinder correction so that ruled out off the shelf pop-ins.
The next thing goes back to my previous bifocal overlay mask. Diving mainly in Maine we generally do not have what you would call magnificent visibility. While being able to keep track of a buddy in the 10-15 foot range is typical the prime visuals are closer and tend to be on the bottom. With the bifocal mask I tended to swim low, following the bottom like an anteater, nose down. In a moment of error I happened to loose this mask (another story) When I started diving my non prescription mask I had a sudden surprise. All of a sudden I was swimming 2-3 feet from the bottom and getting a more panoramic view! What I realized is that with the bifocal mask and the tendency to be looking down I was being sucked into the near vision portion of the lenses and adjusting my physical distance for some intense close-up vision. While my eye's would be a little weary after 2 dives I could still read all of my instruments OK so I finished the summer diving non prescription while I sorted this experience out. On top of that with the bifocal mask instrument positioning was a little tedious for the best vision.
The next thing I learned about was my diopters. It turns out that I am an oddball (what's new!) Both my near and far corrections are positives. Most folks have a negative diopter for distance correction and a positive for near. Due to this fact a single focal lens for one sort of viewing will ruin the other. In my case my prescribed distance correction gets me about 1/2 way to perfect near correction. Since I can already read my instruments uncorrected this is just fine. As an aside, nearly all of the off the shelf pop-in prescription lenses are negative diopters. There are some brands that offer a few positives but this will really limit your mask choices.
So now I have a brand new single focal mask with prescription overlays that is waiting for it's first dive. In topside tests it provides great far vision (nicer than my street glasses). The near vision tests were right where I expected and will be fine.
I hope this journey is helpful.
Pete
