peterdev 0 Posted July 9, 2010 On land I use +2.75 to read and look at my camera screen, and +1.00 to drive and see long distance. I need help with seeing my P&S screen underwater - I have a mask with plastic bifocals glued to the lower part of the windows - but always trying to see out of the bottom of the mask is very limiting and uncomfortable, and they are always the first thing to fog up. I have been reading here and discovered that some are putting a "reading" contact lens in one eye, and a distance contact in the other, and that your brain somehow compensates for the differential. My question is - has anyone ever tried putting say a +2.75 lens in one side of their mask, and say a 1.0 in the other. I would be most interested to hear if this could work as I have never tried contacts, and do not really want to start now. Thank you in advance for your help. Share this post Link to post Share on other sites
davephdv 0 Posted July 9, 2010 Your talking about monovision. It is normally done with contact lens. With a contact lens you get no magnification. With glasses that have + lenses you will get a magnification difference between the eyes. For the purpose you are asking about it may work. I have patients whom wear mono contact lenses and have backup mono glasses. I believe most of them use - lenses though. I would still recommend daily disposable contact lenses for what you are attempting to do. Share this post Link to post Share on other sites
secretsea18 0 Posted July 9, 2010 I have prescription mask with larger than normal sized bifocal lenses glued for the bottom for exactly the reason you write about. I have a dive mask optician in Queens who specializes in this sort of thing. Not cheap but he does very good work! If your camera screen is your only problem, use the "Zoom" button to enlarge what you capture on your images to check for focus. While this only will work when you have already gotten an image, it is great to see if your image is in focus and you can move it around so you can see if the eye is in focus on a shrimp, for example. Good luck. Share this post Link to post Share on other sites
AndreSmith 15 Posted July 9, 2010 (edited) Mask precription for monovision is definitely an option. I have used it for about two years now and I love it and I know several other uw photographers that have done the same. You need a a two pane mask. Your dominant eye is corrected for far vision ( if required ) and the non dominant one for close up. You look with your dominant eye through the viewfinder an with your camera's dioptric adjustment you should be able to get perfect focus at any distance and when you need to look at your computer or camera controls etc you are looking through the other eye. Your brain figurees that out so its not like you have to consciously look through one eye or the other. It may feel a little weird on your first dive but you will get used to it very soon. Definitely the way to go in my opinion. Trying to peer through the bottom part of your mask sucks especially if you are hunting for small critters, and yes, thats the part were you always fog up. The adjustment will be a bit more difficult if there is a large difference between near and far vision but with the numbers you give you shouldn't have any problems. Give it a try! Edited July 9, 2010 by AndreSmith Share this post Link to post Share on other sites
davephdv 0 Posted July 9, 2010 Mono vision is not that simple. Some people do very well with it, some not at all, and most are in the middle. It works better with myopic people (-power) than hyperopic (+power). Due to the magnification and lens aberration effects that seem to bother people with + prescriptions worse. With mono it is normal to start with the dominant eye for distance. It doesn't always works that way. Some end up with the opposite. Some don't have a dominant eye. Some can never adjust to it. There are some breaks you get with using it for diving. You don't need to have excellent distance vision for driving. You don't spend long hours working on your computer. Meaning the less the visual demand the easier it is to accept the compromises introduced to your vision by mono vision. As always, mono vision will work much better with contact lenses than with glasses or a prescription mask. Also for diving and surfing, daily disposable contacts are best. This is assuming that you take proper sanitary precautions and use them as intended. Of course for medical reasons some may not be good candidates for Contacts. Still there are few people who couldn't be fit with them for a specialized application like diving. Share this post Link to post Share on other sites
peterdev 0 Posted July 10, 2010 Thanks you for sharing your knowledge and practical experiences. It would appear that this solution is somewhat person dependent – and that not everyone is able to adjust to having each eye see differently. I am so frustrated with my lack of vision under the water – my kids see 4 times the amount and detail that I see on every dive. I am determined to find a better solution than the "Bifocals" in the bottom of the mask so I am ready to try both methods and see if I can make one work. I have taken 2 pairs of glasses and combined them so that I have +2.75 in my right eye, and +1.0 in my left eye, and I can function this way – I have driven a car, can see all the road signs at a distance as well as the car gauges. It seems that estimating the proximity of other cars, as well as estimating speed is compromised. Each method seems to have advantages and risks – so I would be very grateful for some additional advice: The mask solution is the least invasive – is any particular window shape, eye to window distance, or specific brand preferable? How do you determine which is your dominant eye? How difficult is it for someone of 56 who has never worn contacts to adjust to them? Should I take the natural magnification of the mask to water interface into account when getting the mask lenses and contact lenses? I am going to get my eyes examined next week before I take the next steps. Again – than you in advance for sharing your experiences and knowledge. Share this post Link to post Share on other sites
eyu 27 Posted July 10, 2010 (edited) Welcome to the presbyopia club with the need for reading glasses. I have my mask fitted with custom reading lens to see near objects by: http://prescriptiondivemasks.com/ I get the "executive style readers" and have the top of the reading glasses 2 mm below the center of my pupil. By doing so as I look forward for no correction and slightly downward for reading correction. The key is the reading lens placement so that there is no straining. For you since you are far-sighted, have your +1 prescription placed in the upper part and the +2.75 placed in the lower part. I've sent my mask back to have the lens readjusted, they stand behind their work and their advice has been right-on. Edited July 10, 2010 by eyu Share this post Link to post Share on other sites
secretsea18 0 Posted July 10, 2010 How do you determine which is your dominant eye? Easy. Which eye do you look through the viewfinder with? That is the eye that is dominant. For most people it's the right eye. (In my case, I'm an eye lefty!) Share this post Link to post Share on other sites
eyu 27 Posted July 10, 2010 Eye dominance is easily tested by extending your arm and sticking up your thumb. Now look at your thumb covering one eye at a time. The uncovered eye in which the thumb moves is the non-dominant. The uncovered eye in which the thumb does not move is the dominant eye. Share this post Link to post Share on other sites
davephdv 0 Posted July 11, 2010 Eye dominance is easily tested by extending your arm and sticking up your thumb. Now look at your thumb covering one eye at a time. The uncovered eye in which the thumb moves is the non-dominant. The uncovered eye in which the thumb does not move is the dominant eye. Eye dominance is easy to test. If your lucky easy to interpret. However if your not lucky it can be very difficult. Even then it may be that you should set up your lenses the opposite of eye dominance. If you have your own mono system and it works you probably have your answer. That's where I would start if you came in my office. Most people can adapt to contacts at any age. Some can't at any age. I would always start by seeing your doctor and getting a proper prescription. You can't imaging how much time and money this could save you. Not to mention your eyesight if your over 40. Bifocals are a good choice. Carefully describe to your doctor your special needs. BRING YOUR TOYS WITH YOU. Including your mask. Share this post Link to post Share on other sites
rtrski 20 Posted July 14, 2010 (edited) I'd have to concur with the bifocal mask concept (although I will confess, I'm one of those that davidphdv warns about who just cannot adjust to monovision - tried it with disposable contacts once and it gave me vertigo practically). Got mine from http://rxdivemask.com/ ...pricing is probably about the same as the link to Prescription Dive Masks in CA that someone else already posted...sent them my newly purchased mask with a sharpie line on it where I wanted the bifocal break to be, and they bond the corrective lenses inside. Good quality glass - no fogging problem at all. It's nothing like the cheaper glue-ons for near-correction only as it doesn't leave a huge border between 'uncorrected' and 'corrected', and you can tell them where you want the line to suit your mask and diving style. As others have said, custom-ground mask lenses with bifocal correction are not cheap. But having used them for my first trip after having to go to bifungals ('fungal' as in 'needed by old men' as my wife says ) in the first place, I found them invaluable. I used to wear a HydroOptix mask which was great for FOV and far vision correction, but actually forces your eyes to work harder to accomodate for near vision, so once I needed bifocals for dry life I knew that mask was over for me. The other reason your kids might see 'more' than you though is that they don't have the camera so their attention is never split from environment (aside from gauge checks) - but rather than take that as irritating, use them as spotters! All that said - I'm also trying to force myself to use the actual camera optical VF instead of the 'screen' which no longer requires you to use 'near' vision for shooting. I can't see focus well enough on a tiny screen in bright sunlight anyway, so my after-the-shot checks are really just of the superposed histogram to try for lighting adjustments. Edited July 14, 2010 by rtrski Share this post Link to post Share on other sites
Oceantony 0 Posted August 4, 2010 Leonard Maggiore did an excellent job with mine. I highly recommend him. About $200.00 with a very good mask and bifocals prescription! Great job! Share this post Link to post Share on other sites
kyzy23 0 Posted August 5, 2010 Great info. I had two prescription masks. @ the time I bought one I was told by another diver that used the same mask to "Have two. If you drop one a certain way it will shatter into a billion pieces". Hence, two masks and a lot of money. It came true and the other clients on the dive boat were not happy with the end result. I was getting annoyed @ the up and down movement I always had to do to see out of the mask - bifocals. A DM I have known for years mentioned "contacts". I never had any luck being fitted but things have changed a great deal in that field so I asked my eye doctor about some. One for distance and one for close up. He asked me to extend my arm and pretend I was shooting a gun. He was able to establish right away which eye should have which lens. I can't tell you what a great decision that was - it has made an enormous difference. I can see out of the view finder and I can also see in the distance. Yes, I have heard they are not for everyone. Good luck and Happy Diving. Share this post Link to post Share on other sites