The Tusa Geminus Dive Mask's unique 2-window design offers exceptional visibility and low-volume comfort while incorporating TUSA's patented 3-D Strap and Round Edge skirt technologies. A newly designed skirt mounted Quick-Adjust Buckle System further enhances comfort and ease of fit.
Simply, the Geminus leads where others will follow.
Clear/Black, Clear/Cobalt Blue, Clear/Fluorescent Yellow, Clear/Transparent, Black/Metallic Silver, Black/Metallic Red
How To Order
Step 1 - Choose Your Mask & Lens
Visit our Prescription Dive Masks page to view our full range of masks. On each of our masks you have the option to add the lens corrections to your order. Simply choose your favourite, add the lens correction and checkout online.
If you already have a mask we are more than happy to bond prescription lenses to a mask you supply to us - provided the mask has tempered-glass faceplates. This can be a new mask sourced from your local dive-centre or dive-shop, or a mask you are already using. Simply choose the 'Supply Your Own Mask' option from the shop.
Step 2 - Upload your Prescription
Next please send us a copy of your prescription. You can:
Photocopy and post to Dive Sight LTD, Unit 3, Carlisle House, 99 Carlisle Street East, Sheffield, S4 7QN
Please ensure that your opticians name and address are clearly visible on the prescription.
Please note that due to regulations we are unable to supply prescription masks if you are registered blind and we cannot supply to anyone under 16 years of age. Dive Sight is a professional optical service and we are not here just to sell you a prescription dive mask, we are here to optimise your underwater vision and maximise your diving pleasure. To do this, we need to be absolutely certain that the prescription details you provide are completely accurate and less than two years old.
It is very important that we have your precise prescription details and ophthalmic regulations require us to see a copy of your actual prescription form. Ideally, we need to see this at the time the order is placed.
This can be scanned and e-mailed, or sent as a hard copy. Address details are shown below. This is to safeguard your interest, as your mask will be custom-glazed and cannot be offered for resale. We are required to see a copy of the prescription prior to dispatching your order.
If you do not fully understand the information on your prescription or have any queries relating to your prescription just call us on 0114 3273140 and we can answer any questions you have.
Step 3 - Upload your Pupil Distance
Last, but not least, we will need a very simple measurement, to ensure you get the very best results from your prescription mask. This is the measurement of the distance between your pupils, (your PD) when looking straight ahead.
An accurate PD measurement enables us to position the optical centres of the lenses exactly in-line with the centres of your eyes, to ensure maximum visual comfort. This measurement can be obtained from your optician or you can either use a mirror to take the PD measurement yourself, or get a friend to assist you. The easiest way is to take a piece of firm card and hold it below your eyes and then make a pencil mark directly in line with each pupil and measure the distance between the two marks in millimeters (mm). A typical adult measurement will be between 58 and 70mm.
As eye care professionals Dive Sight ltd will not work to “approximate” values. We will produce your mask to your precise prescription to ensure we achieve the optimum visual acuity, making your vision underwater as good as it is on dry land. All our prescription lenses are made from optical glass, which minimizes distortion, reduces fogging and offers maximum scratch resistance. The corrective lenses are permanently bonded to the inside of the mask faceplates.
If you are unhappy with your purchase, we will take it back and refund the cost of the mask, but we cannot reimburse you for the cost of glazing as the lenses we fit are custom made to your specific prescription, and cannot be reused.
All Dive Sight masks are custom made to each individuals precise prescription, and carefully checked at every stage of production. As such, customers need to allow 28 days for delivery from receipt of initial order. In the event of your chosen mask being out of stock or unsuitable for your prescription, we will contact you and advise on alternatives.
All our dive-mask lenses are made from optical glass, which minimises distortion, cuts down fogging and offers maximum scratch resistance. The corrective lenses, to your precise prescription, will be permanently bonded to the rear of the mask’s original flat ( plano ) glass, though, in cases of very high prescriptions, they may be bonded to the front surface.
These are used to correct ‘long-sightedness’ ( Hypermetropia ) This describes the condition when distant objects can be seen clearly but near objects are blurred. The higher the power of a plus lens, the greater the effect of ‘tunnel vision’. This can necessitate a special choice of lens for higher + powers.
These are used to correct ‘short-sightedness’ ( Myopia ) This is when near objects can be seen clearly but distant objects appear blurred. The higher the power of a minus lens, the thicker the lens edges become, giving peripheral distortion’. This sometimes requires lenses to be made to a specific size or in a specific material.
The 'cylinder' value of a lens is used to correct astigmatism, the condition where one part of the eye has an irregular curve ( instead of being round, it is shaped more like a rugby ball ). To further complicate matters, astigmatism may also occur at an angle ( this will be the case if you have an ‘axis’ value on your prescription.) If these problems are not corrected your eye cannot compensate, other than to a small degree, so your vision will be distorted and blurred. The only way to achieve correction is by using lenses with a cylinder value. 'Off the shelf' lenses do not have any cylinder correction. This is one of the reasons why we do not recommend their use.
Bifocal ( Read add )
As we get older, usually starting around the mid 40’s, the mechanism that allows the eye to focus ‘up close’ becomes increasingly less efficient and ‘reading glasses’ become a necessity, even though other spectacles are not generally required. Obviously this can present a problem when diving, as some correction will be needed to read gauges, or observe small objects without touching a delicate environment, such as a reef. To address this issue, we can supply masks with 'bifocal' lenses, whereby plain lenses or distance prescription lenses have a small, reading lens segment incorporated into the lower part of the lens.
Precise Prescription - Optimum Vision
DiveSight is a professional optical service and our primary aim is to give the underwater vision you need in order to get the optimum satisfaction and enjoyment from your diving. Any mask supplied by us will be glazed to your exact prescription. We do not use 'off the shelf' lenses with the nearest, approximate power, as is often the case with other websites that offer 'prescription lenses'.
The ‘power’ of the spherical and cylindrical correction ( your prescription ) is measured in dioptres. Ready-made, 'off-the-shelf', ‘prescription’ dive masks or swimming goggles, have lenses which come in 0.5 dioptre increments. As a result, they will only be to the nearest approximate power to your prescription, relying on your eye’s flexibility to try and adjust for the uncorrected error. Moreover, these lenses only correct the spherical part of the problem, with no correction for any cylindrical (astigmatic ) element of the defect. In order for us to supply you with the correct lenses, it is essential that the prescription information you give us is totally accurate and up-to-date.
If you are unhappy with your purchase, we will take it back and refund the cost of the mask, but we cannot reimburse you for the cost of glazing as the lenses we fit will be to your specific, personal prescription and the mask cannot be offered for resale with these lenses fitted. (See Terms and Conditions)
Liam was SUPERB! I had a very short timeline to get my mask sent to him and for the lenses to be added and sent back before I left for Sipadan. It was extremely smooth - he communicated every step of the way and made sure I got the reassurance to manage my stress! The mask itself, I was worried it was going to look awful but in fact, it was only when I mentioned it that people were like "ohhh yes I see now". And best of all, I could see perfectly - my NDL, which of course is the most important thing! Thanks Liam, cant recommend you and Divesight enough (recommended by Kieran in Robinhood Watersports Leeds).
Great advice, easy process and regular updates. And as promised (by the dive store that recommended me) the dive mask is exactly like wearing glasses. Really looking forward to our silver wedding anniversary trip being able to fully see underwater for the first time in over 20 years! Thanks Liam and Dive Sight
well after 72 tropical dives and having issues with plastic inserts continually fogging. Time for a change sent liam my Hollis Mask and my prescription +7.5 and within 2 weeks the bonded lenses were back. So off to the Philippines wow wow wow, I was able to see all the small critters as well as being able to take macro photos. The good part was not once did my mask fog up in over 30 dives. I am well impressed with the service from Liam and his team. If you wear prescription lenses then this is a must. Thank you Liam for the service and the email contact.
I havent used my old mask again since getting my prescription one from Dive Sight. it is awesome. so convenient. Only took two weeks from ordering to delivery. quality is perfect. I really would recommend to anyone who normally faffs about with contact lenses before diving. prescription masks are the way to go! thank you very much for my mask!! 😀😀
5*. I sent a paper copy of my prescription in the google box and 2 weeks later my Goggles returned. Prescription was spot on and made my experience 10x’s better. Anyone who wears glasses I highly recommend getting the prescription lenses fitted .
My husband and I had new facemasks updated with prescription lenses by Dive Sight, and are delighted with the results. The clarity of vision was a huge bonus when snorkelling and diving in the Maldives!
Ordered two masks from Liam and the team at Drive Sight for myself and my wife. Order process was very easy and prescriptions were spot on. Good choice of masks available and the Cressi mask we settled on is excellent. Really looking forward to our holiday in Feb so we can test the masks under the water. Great service and communication. I would definitely recommend dive sight.
Brilliant lenses... got to me just in time for flight to Mauritius...still quite a lot of reef left...saw massive Big Fin Reef Squid today...mask itself (Cressi) a tad loose or/porous...but very pleased
Like many, I found my aged eyes could no longer see enough to read my gauges or dive computer (again) or well enough to see well at distance, so I went for Tusa Geminus mask, which I find fits well and franklin split lemses. I was delighted with the result - much better than squinting though bifocals. The email updates from Liam were very useful, particularly given the usual Covid uncertainties of supply. Whilst I hope not need a new mask too soon I would certainly recommend Dive Sight lenses.
Age was getting the better of my eyes and making it difficult to see my dive computer or gauges when diving. The ordering process is straightforward and the quality of the lenses, first class. I marked up and sent in my own mask for custom bi-focal lenses which were manufactured, fitted and the finished mask returned to me within a fortnight. I've since tested the mask with 22 ocean dives and have been very impressed. I'm not sure I've ever seen macro life so clearly, and my computer and gauges are as clear as a bell. I would absolutely recommend Dive Sight to anyone who, like me, finds their eyes letting them down a bit as the years pass.
Have used Dive Sight Ltd three times now and the service has been great, everything they say they are going to do they do to a high standard. Liam is also very easy to talk to as well. Great Company Great Service. My Mares Mask is now 9 years...Thanks
Excellent communication from Liam throughout the whole process. Work was carried out quickly and mask arrived in advance of advertised timescales. Really pleased with everything and will certainly be recommending to my diving club members. At last I can see!
Really pleased with the quality of work from Dive Sight, thanks Liam and crew. Got my Atomic Aquatics Frameless 2 mask back and I’m really pleased with it to say the least. Only had the chance so far to try them on land but the field of vision for the bifocals is perfect. Also like the little video snippets that keep you updated on the work progress. Can’t recommend them highly enough 👌.
what a great result!! I ordered a new mask with bi-focal prescription lenses ordering we easy, and there delivery times we're spot on, in less than 2 weeks the new mask was delivered. did my dives using the mask this week and all my problems reading the gauges and notes were all resolved. I woukd recommend and use Dive Sight thank you matthew
I ordered a diving mask with a high and complicated prescription for my son. The service was exceptional, I received personal email correspondence right away, with an accurate time for delivery. Dive Sight made a great effort to get the mask to me at short notice. The mask itself is excellent quality, much better than sports glasses I have had made by other companies for football. I would thoroughly recommend this company.
great company to work with, Liam provided regular updates as my mask was prepared and it arrived safely ….. I’ve now used my mask for the first time here in Bahrain and it has exceeded expectations …. The quality of the lenses are excellent and the mask has transformed my diving experience and allowing me to go further in my certifications …… well done ! And keep up the good work 😀👍 …… David, one very happy customer.
Just a great company to deal with! Liam turned around my order in less than a week, I was informed at each stage of the process with fantastic customer service. Dive Sight offer the best range of masks and the workmanship is the best I have seen, I would recommend Dive Sight to anyone who needs any type of prescription mask. Super happy! Thank you Liam
What can I say...Once again Liam and his team have come up trumps! I've always got my prescription dive masks from here and been totally satisfied with both the product and the customer service...but last week they went 'ABOVE & BEYOND' for me. I messaged Liam to say that I had accidentally smashed my prescription dive mask (pesky cylinder!) and urgently required a new one, to be completed and delivered before 19th July. Liam replied instantly and said they would do their best to help me, but they were quite busy. On the 18th July my mask was delivered!...what can I say but THANK YOU, THANK YOU, THANK YOU! I would totally recommend them, I will never use anyone else, even though I live in Cyprus 😊
I had been struggling to see smaller details during my dives and then it was getting harder to see my computer. I was given Divesight’s details and wow what a transformation. I didn’t realise how much I had been missing during my dives until I put my new prescription lens mask on. Wish I had done it sooner. The customer service and communication is great, I highly recommend this company and products.
Yessssss, I can now see what I am taking photographs of 😂 Extremely happy with my prescription lens mask. Great service, lots of questions were answered for me before I placed my order. Really helpful staff. I recommended to a fellow diver and she is pleased with her mask too. Definately recommend these guys and will use again in the future when I need to upgrade.
My dad bought me a mask from Dive Sight Ltd. I have a very high long sighted prescription. Roughly +8 each eye. I also have a slight astigmatism. No issues with lenses, they’re surprisingly thin. Everything is sealed nicely. No complaints from me. :)
I have used five site a couple of times to purchase a prescription dive mask. What I particularly like are the full size Lenses as opposed to the stick in type you can get. They have a fantastic service and support regime and very reasonable pricing. and will definitely use again👌
I have used this company 3 times now. As an active scuba diver I need to be able to see as well under the water as I do with my bifocal glasses on land. Obviously having lenses bonded into a mask is not cheap but the quality of work done by Dive Sight Ltd. is excellent. I have found them to be very helpful when I needed to ask a question, and the turnaround time for completing the work is also very good.
Many thanks to Liam at Dive Sight for advising me about which diving prescription lenses are most suitable for me. I usually wear varifocals and I’m really pleased with my new Atomic subframe mask (medium-size as I’m female) with bifocal prescription lenses. Although the lenses are slightly smaller than previously supplied they still go into the V shape of each mask lens so I can see my dry suit inflation etc when I look down. And thanks also for promptly replacing the Atomic mask box when the original one supplied was broken. Excellent customer service!
After an I bought a prescription snorkel mask a few years ago from Divesight.I was very shortsighted,so I was delighted to get a mask that fitted my unusual prescription. After a recent eye operation ,my eyesight had improved considerably in my left eye.I sent my mask to Divesight and they changed the one lens.Once again the service was brilliant and I am very pleased with the clarity offered by the mask. I highly recommend this company. R.Wilshire
Just tried my prescription mask for the first this weekend Excellent what a difference reading guages instead of trying to make my arm longer and squinting eyes. went for bifocials the fit is perfect After all those years of mucking about with stick in lenses losing them we have all been there at some point should of done this years ago worth the money. Recommended to my dive buddies. excellent service from Liam thank you Jeff
Have had prescription masks from Liam Ward for a number of years and highly recommend Dive Sight Ltd. Excellent quality and workmanship, great advice and customer service. I always recommend this company to our dive club members and our professional dive team.
I've been using Dive Sight lenses in my masks for 20 years. The lenses are a quality item, and perfectly restore my vision. The lenses outlast my masks, and my masks last about 10 years. Minor changes in eyesight from year to your do not require new mask lenses. The lenses were an investment, designed to last. Great, quick and friendly service from Liam for my last recent order.
Hi All, I am not one for social media normally, however I felt I had to post this for you all. I am an AMG rebreather instructor. As you will understand being able to see my computer and tables is absolutely essential. My Cressi Penta mask got broken on the boat, I bought another mask a Cressi Matrix. Liam at Divesight has kindly removed them from the old mask and put them into my new one at a very competitive price. all during Covid too. I am now eagerly awaiting being able to dive again when restrictions are lifted. The mask looks awesome well done and thanks to Liam.
Hi, I ordered a mask from Liam at the start of the year, super easy to do through the website. Really pleased with the mask, turn around time was better than advertised and the mask is great and makes a big difference to my visibility. Unfortunatly I’ve only been able to use in the pool so far due to covid situation
Very pleased with my mask and plus the service was very professional. The lenses that Liam fitted look great and my vision through the mask is great, can’t wait to use the mask and see under water. I would very much recommend DiveSight.