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Prescription Lens Masks
We have been told by our suppliers that we sell more corrective lens dive mask than the whole of the rest of the Australian dive industry combined. It's because of the detailed information on this web page, plus our excellent customer service and everyday low prices. Please read the following information carefully. Then join the thousands of divers and snorkellers who are seeing clearly underwater using a corrective lens mask from The Scuba Doctor.
Prescription vs Corrective Lens Masks
If you wear prescription glasses, diving and snorkelling masks fitted with lenses with your exact prescription can be obtained. But it's very expensive and time-consuming. Most divers and snorkellers don't require this expensive solution and their needs can be solved with less expensive and quick to obtain corrective lens mask solutions. The important thing here is to make sure that the variety of your needs are taken into consideration and the right solution is chosen.
Negative Correction Lens — If you are a snorkeller you probably just need to see objects in the distance, therefore a distance only correction lens can be used with selected masks. That's the case for many divers as well. The solution is what we call a negative corrective lens mask — a negative correction to the whole lens, for short/near-sighted people with myopia.
Positive Correction Lens — For some scuba divers and snorkelers it's the reverse and and they need positive correction lenses for near vision issues. The solution is what we call a positive corrective lens mask — a positive correction to the whole lens, for long/far-sighted people with hypermetropia.
Bifocal Correction Lens — Some scuba divers just need a bit of help reading their gauges, dive computers, or camera controls. The solution is what we call a 'bifocal', or 'gauge reading', corrective lens mask — clear or planar on top and a lower pane with positive correction for reading.
Sometimes snorkellers and scuba divers have eye shapes that require lens shapes not available with corrective lenses. They need an exact, full prescription lens mask solution, and we can't provide it.
Also, some divers may need both distance correction to see the underwater life, and near correction to read gauges and dive computers. Therefore, depending on your prescription, true bifocal, or truncated, full prescription lenses may be required — distance correction on top and a lower pane with positive correction for reading. This is what we call a full bifocal prescription lens mask solution, and we can't provide it.
Your optometrist is the best person to advise you as to which of the above solutions are right for you. Please show them this web page so that they can understand what we can and can't do. Then they can give you the right and left eye correction values we need to provide your underwater vision solution.
Diving/Snorkelling Mask Corrective Lenses
The Scuba Doctor is able to provide the dive and snorkelling masks listed here already fitted with pre-made corrective lenses that correct close to your prescription, not exact. This is a good solution for most scuba divers and snorkellers with low astigmatism.
Corrective lens mask: the mask, plus two separate correction lenses.
Supplied with the corrective lenses fitted, plus the original normal lenses.
We can offer dive masks in a range of correction strengths to suit most people. We offer positive and negative corrections and bifocals. Bifocals are great for people who are long sighted and just struggle to view their gauges. The lenses we supply are not the stick on type, they are complete replacements for the current lenses. We can therefore only supply these on a select few masks.
Some of the masks with optional vision correcting lenses can be obtained with either a '-' (minus/negative) dioptre (e.g. -1.5 to -9.0), or a '+' (plus/positive) dioptre (e.g. +1.0 to +4.5), typically in 0.5 increments.
Some divers require negative distance vision correction, that is, the diver has 'near-sightedness' and the Rx Sphere value is a '-' dioptre.
Other divers require a positive correction, that is, the diver has 'far-sightedness' and the Rx Sphere value is a '+' dioptre.
To order, you can consult your eyeglass, or contact, prescription for the proper amount of spherical power correction. A spectacle prescription is usually written in the following form:
| sphere | cylinder | axis | |||
| OD / R | -3.00 | / | -0.50 | x | 180 |
| OS / L | -3.50 | / | -1.00 | x | 180 |
In order to calculate the power you need to take into account the two aspects of your prescription.
- The sphere (or sph) is the main part of your prescription and will be '–' for short-sightedness (myopia) and '+' for long-sightedness (hypermetropia).
- The cylinder (or cyl) is the secondary part of your prescription and refers to the amount of astigmatism you have.
We need the dioptre (diopter) value for each eye. When reading your prescription, 'OS' means your left eye, and 'OD' means your right eye.
You could base the power you order primarily on the amount of short or long-sightedness you have. If you also have a moderate degree of astigmatism (up to 2.00), you could also incorporate up to half of this to choose the most appropriate power. If the result is a quarter dioptre prescription, then you should typically increase to the next higher/stronger dioptre. For example, if the Rx is -1.75, then increase to -2.0 dioptre. If the Rx is +1.75, then increase to +2.0 dioptre. If one eye needs no correction, then order a 'Normal' or 'Plano' lens for that side.
If this all sounds very complicated, it's because it is! You will find websites that let you enter your script values to calculate the two values we need. We know the formula they use, but our optometrist friends tell us using this method would often lead to disappointed customers. It's just not that simple.
The decision about the values you need is best done by your optometrist as they know best what's going on with your eyes, and sometimes those other values in your script come into play.
Once you know the dioptre values you need, you can then select a mask for which the range or dioptre values available matches your requirements.
Bifocal or 'Gauge Reader' Corrective Lenses
Finding the numerals on your gauge too small, especially in the dark? Finding your arm is not long enough, but have pretty good distance vision? If you answered yes to these questions, then you probably have presbyopia, a condition where the eye exhibits a progressively diminished ability to focus on near objects with age. On the surface, the fix is reading glasses (those things you always forget just when you need them most). Bright light also helps, as it constricts the pupils, and decreases spherical aberration. Some people use prescription bifocals, trifocals or multi-focal lenses.
Underwater the solution is a 'Gauge Reader' mask fitted with what the dive industry refers to as Bifocal corrective lenses. These underwater bifocal corrective lenses for masks aren't quite what people are used to with bifocal prescription glasses.
With Gauge Reader dive mask bifocal corrective lenses, the lower pane (roughly a third) has the plus dioptre reading correction, and the rest of the lens is 'Normal' or 'Plano'. That's why they're referred to as Gauge Reading lenses. You need to know the dioptre value for your reading glasses.
Bifocal lens mask with gauge reading correction lenses.
Normal (plano) vision for top two thirds and "reading" (plus) correction for bottom third.
Supplied with the bifocal lenses fitted, plus the original normal (plano) lenses.
Bifocal / Gauge Reading corrective lenses are typically available in a dioptre range of +1.0 to +4.5, in 0.5 increments. If you have a quarter dioptre prescription, then increase to the next higher/stronger dioptre. Your eyes will inevitably change and within a few years, you will need the stronger dioptre. Now you can select a mask that has Bifocal / Gauge Reader corrective lenses available with the dioptre value(s) you need.
Note: The bifocal correcting mask lenses we sell have the reading correction attached via a permanent bond by the lens manufacturer. The correction is not an after-market 'stick on' or 'glue in' lens that is not permanent. Our own experience, plus that of our customers, very plainly tells us that none of the after-market 'stick-on' solutions work well, and thus we don't bother selling them.
Please note that all of the masks listed here can have corrective lenses fitted, but only a few of the masks can have bifocal, gauge reading corrective lenses fitted.
What Corrections Do We Offer?
We offer the following levels of prescription/correction, in half dioptre increments:
- Minus lenses from -1.0 to -9.0*
- Plus lenses from +1.0 to +4.5*
- Bifocal lenses from +1.0 to +4.5*
* available on selected masks only.
Please Note: The scripts issued by optometrists use quarter dioptre increments. We can only provide half dioptre increments. This is another reason why you should consult your optometrist, as they will be able to come up with the values you need.
What If I Have Astigmatism?
None of the 'off the shelf' corrective lens masks correct astigmatism, so if the majority of your prescription is astigmatism, or you have astigmatism over 2.00 dioptres, you will need a custom made product for best visual results.
If your astigmatism is less than 2.00 dioptres, or is not the majority of correction, then the corrective lens mask solutions we can provide should be fine. This is another reason why you should consult your optometrist.
Please Consult Your Optometrist
We strongly recommend that you consult your optometrist about which underwater vision correction solution is best for you. We recommend you show them this information. Your optometrist will be able to work out which corrective solutions are available to you and make recommendations as to what to get, plus provide the two dioptre values we need.
We are not optometrists and can't read your script to determine if a corrective lens mask will work for you. Correction lenses typically will work for the vast majority of people, but some eye shapes can't be accommodated this way.
Your prescription may need to be changed because the distance between the lens of your diving mask and your eyes typically is different from the distance between your eyeglasses lenses and your eyes. (This also is one of the reasons your contact lens prescription is different from your eyeglass prescription if you have moderate or high myopia.) An eye care professional specialising in sports eyewear can adjust your prescription for underwater use.
Your optometrist will also be able to provide you with the best spherical correction dioptre values for your left and right eyes given the half dioptre increments of corrective lenses. Then you can order your corrective lens mask from The Scuba Doctor with confidence in achieving a great outcome.
Whatever your preference, there are plentiful corrective options available to ensure that everyone can see clearly to experience the beauty and wonder of the underwater world.
Recommended Optometrist:
Melbourne: David Glennie is an optometrist and experienced scuba diver. His team can check your eyes and translate your script into the values we need for your corrective lenses. They can even show you how it will work.
David Glennie, Karingal Optical
Shop 39, Karingal Hub, 330 Cranbourne Road, Frankston VIC 3199
Tel. 03 9789 4811 www.facebook.com/KaringalOptical/
Fitting the Mask Corrective Lenses
If you buy a complete mask with two corrective lenses from The Scuba Doctor, we will fit the lenses to the mask for you before sending the mask out. You will also receive the original normal (plano) lenses, placed inside the packets the corrective lenses came in.
Corrective Lens Mask Delivery
Order today and your mask with corrective lenses will be assembled and usually Ship the next Business Day.
We typically place orders for your mask with corrective lenses with our suppliers the same day we receive the order from you. In some cases, they will be assembled and shipped directly to you from the suppliers the same business day, or if not, the next business day. Our suppliers are Sydney based, so you need to allow for the usual postal delivery times for the package to reach you from Sydney.
Colour Options: Many of the masks are available with heaps of colour choices. However, sometimes our suppliers get low on some colour options. Please enter any other mask colour options you'd be happy with in the comments during the checkout process. Then we have options to switch to so that your order isn't delayed.
Other Considerations
Custom made prescription lenses made to your exact prescription are sometimes preferred by more advanced divers, for those shooting underwater photo/video, or those who need a bifocal lens with two different types of correction in each lens. We suggest you try Ozbob Scuba for custom made prescription scuba masks.
Because you asked... the negative and positive vision-correcting mask lenses we sell have the magnification ground into the lenses themselves. The bifocal gauge reading correction is attached via a permanent bond by the lens manufacturer. The correction is not an after-market 'stick on' or 'glue in' lens that is not permanent. Our own experience, plus that of our customers, very plainly tells us that none of the after-market 'stick-on' solutions work well, and thus we don't sell them.
Contact Lens Wearers: Not all contact lenses are suitable for diving. Gas permeable lenses (GP lenses) can 'dig' into the eyes below certain depths, because of the pressure. Soft contact lenses can collect waterborne organisms and become contaminated, causing eye infections. If you wear contact lenses under your mask for diving, you need to make sure you blink a lot. Excessive starring can cause bubbles to form underneath your lenses and which may cause minor discomfort and temporary blurring of vision. Also, be sure to have a spare set of contacts (or glasses) available in case you lose a contact lens underwater.
Health Fund Refunds
As best as we can tell, you will be unable to claim a refund from your health fund for the supply of a corrective lens mask. Most health funds require a medical provider item code for a claim to be successful and no dive manufacturer or dive shop we know of has this. However, you may wish to check with your health fund to see if they are more generous.
More Information
For more information please see our Scuba Buying Guides: Buying a Great Dive Mask and Avoiding Mask Squeeze, plus our Dive Gear Features pages: Mask Features and Fixing Underwater Vision Problems.
Note: Diving/snorkelling masks are very different to Swimming Goggles. See Goggles vs Masks. We have available Prescription Swim Goggles.
J3 Swan Island Submarine
Wreck Dive | 
Boat access
Diesel Electric Submarine | Max Depth: 8 m (26 ft)
J3 Submarine
© Unknown
The J3 Yellow Submarine, originally HMS J3, later HMAS J3, also known as the Swan Island Sub, is one of the J class submarines designed and built during WW1 by the British Royal Navy.
The J3 submarine, lies in 5 to 8 metres with parts of the hull above the surface.
Diving the J3 Submarine
J3 Submarine Propellers
© Royal Australian Navy
The J3 submarine lies within the Prohibited Area of Swan Island (Department of Defence) and is therefore out of bounds.
While you can't dive the J3 Submarine unless you were to obtain special permission, you can touch two bronze propellers from this submarine — the battery-powered ones, not the main diesel-driven propeller. They were removed and are on display outside the Queenscliff Maritime Museum.
The J3 lies upright on the seabed in 6 metres of water with the upper deck and superstructure protruding above the water at all times. The bow of the submarine faces east-north-east and is approximately 100 metres from the shore of Swan Island. Strong tidal conditions exist on the site at 90 degrees to the long axis of the vessel. Diving is safely carried out on the lee side of the vessel during the running tide which can run up to 2 knots at full tide.
J3 Submarine image and sonar cross-sections courtesy of the CSIRO
© CSIRO
J3 Submarine History
J3 Submarine (circa 1919)
© Royal Australian Navy
Originally HMS J3, later HMAS J3, this is one of the seven J class submarines designed and built during WW1 by the British Royal Navy. The J class of submarines was a seven submarine class developed in response to claims that Germany was developing submarines that were fast enough (22 knots) to operate alongside surface fleets. The rumours were actually false.
The J Class design brief was for a submarine to operate on the wings of battle fleets, diving at the commencement of engagements, and picking off stragglers, damaged ships, and acting as an anti-submarine submarine.
This class of submarines were the only design of submarines ever to have had 3 screw propellers, and at the time were the fastest subs around with a surface speed of 19 knots (35 kpm). Six J class submarines were completed during mid-1916, while a seventh entered service in 1917.
HMS J3 commissioned in the Royal Navy on 27 April 1916 and was allocated to the 11th Submarine Flotilla based at Blyth, Northumberland. The wartime complement was 5 officers and 40 sailors.
HMS J3 Submarine Operations
HMAS J3 Submarine
© Royal Australian Navy
On 18 August 1916 a German signal was intercepted which made it clear that the German High Seas Fleet would be putting to sea that night. Again the several submarine flotillas were involved in the British counter measures. By midnight 26 submarines were on the move including J1, J3, J5 and J6 sent to patrol areas off the Tyne. In the event, only E23 saw anything of the Germans.
Although larger and more powerful than previous British submarines, the J class could not keep up with surface vessels and operated independently during the war. Between them, the submarines sank a U-boat, and heavily damaged two battleships. The J6 Submarine had been sunk in error in 1918 by a British ship.
HMAS J3 Submarine Operations
J Class Submarine Control Room
Source: Royal Navy
Following the conclusion of hostilities in World War I, the Admiralty in 1918 presented the six remaining boats of the J Class to the Australian Government. All the submarines commissioned into the Royal Australian Navy at Portsmouth on 25 March 1919, as tenders to the submarine depot ship HMAS Platypus. The Commanding Officer of J3 was Lieutenant Henry KB Mitchell RN.
The beam tubes were removed from all six J Class submarines before they sailed for Australia. The tubes were despatched separately to Garden Island. The reasons given for the removal were that the beam tubes were not a success and that increased accommodation was required.
On 9 April 1919 HMAS Platypus and the six submarines, escorted by the light cruiser HMAS Sydney, sailed from Portsmouth for Australia, their first two ports of call being Gibraltar and Valetta. On the night of 28 April 1919, the night before the vessels arrived at Port Said, J3's starboard main engine shaft snapped. Thus handicapped she could not keep up with the others and consequently on departure for Aden on 30 April 1919, J3 was in tow of Sydney.
The vessels arrived at Aden on 5 May 1919. On the same day the light cruiser HMAS Brisbane, which had left Portsmouth on 17 April 1919, also arrived. On 7 May 1919, all the vessels sailed for Colombo. HMAS Brisbane took over the tow of J3 while HMAS Sydney took J5 in tow as that boat had also developed engine trouble. J3 was taken in hand at Colombo for repairs. On 31 May 1919, HMAS Sydney, J1, J2, J4 and J7 sailed for Singapore, followed on 2 June 1919 by HMAS Platypus and J3. The vessels were reunited in Singapore from where all except Sydney sailed on 18 June 1919. Sydney sailed for Australia a few days later but did not rejoin the other vessels. On 29 June 1919 HMAS Platypus and the submarines arrived at Thursday Island, although J7 was three hours late because of trouble with her engine lubricating system.
When they arrived in Australia on 15 July 1919, the six submarines were all in poor condition. They were taken in hand at Garden Island Dockyard for refitting. After her refit was completed in October 1920, J3 sailed for the submarine base at Geelong, Victoria. Osborne House, previously a rest home for nurses, was used as the base for the six submarines.
The J3 and J4 carried out a major cruise in Tasmanian waters in January 1922.
The ironclad Cerberus was renamed HMAS Platypus II on the 1 April 1921 and acted as a depot ship to the J Class submarines whilst stationed at Geelong. The Platypus II is not to be confused with the HMAS Platypus which was one of the six gift vessels which escorted the J submarines from England to Australia.
After uneventful service, little of which was spent at sea, J3 and her five sisters paid off into Reserve at Western Port on 12 July 1922. The boats had become victims of the worsening economic conditions of the time, coupled with their high cost of maintenance.
J3 Submarine Details
J-class Submarine General Arrangement
Source: Royal Australian Navy
The J class Submarine Number 3 was built in 1915 at Portsmouth Naval Dockyard, England, and launched on 4 December 1915. At that time the J class were the fastest subs in existence.
It's commonly believed that the J-class submarines were identical in dimensions and layout, but this is not so. Royal Navy drawings placed the J class into two groups of J1–4 and J5–7, and that the bridge of J7 was moved 60 feet aft compared to J5–6. Plans show a difference in overall length between the two groups, with J5–7 at 274 feet 9 inches being 9 inches shorter than J1–4 which were 275 feet 6 inches.
The overall length of the J3 Submarine was approximately 275.5 ft (84 m), beam 23.25 ft (7.09 m) and draught 14 ft (4.27 m) giving a displacement weight of 1,210 t (1,334 s-ton) surfaced and 1,820 t (2,006 s-ton) submerged.
Inside a J-class Submarine
Source: Royal Australian Navy
The J-class submarines were powered by three 12-cylinder Vickers solid injection, direct reversing, 4-cycle, diesel engines of 14.5-inch bore and 14-inch stroke, producing a total of 3,600 HP at 380 rpm. For submerged running there were two Mather & Platt 700 HP electric motors, for a total of 1,400 HP, powered by four banks of 58 cell batteries.
The vessel had a maximum speed of 19 knots (35 kpm) surfaced and 9.4 knots (17 kpm) submerged, with a range of 4,000 nm (7,408 km) at 12 knots (22 kpm) and 2,250 nm (4,167 km) at full speed surfaced. The maximum safe diving depth was 300 ft (91 m). They J-class submarines were equipped with a powerful long-range wireless and were ideally suited to reconnoitre in enemy water.
The J Class submarines principal weapons originally were:
- 6 x 18-inch (457 mm) torpedo tubes (4 bow, 2 beam)
- 1 x 4-inch (102 mm) gun
- The J1, for a brief period, was fitted with Depth charges
J3 Submarine Scuttling
J3 Submarine Wreck at Swan Island
© Royal Australian Navy
On 8 December 1922 the J7 under the command of Lieutenant J. Drinkwater was given sailing orders to tow the J3 Submarine from the Flinders Naval Depot and to berth the J3 near Swan Island in a position selected by the officer-in-charge of the Mine Depot at Swan Island. Where the said officer considered the use of the J3 as a power station and pier. The HMAS Platypus II (ex Cerberus) was directed to be off Swan Spit buoy to assist in the berthing. On the afternoon of 9 December 1922, the J3 was moored safely with shorelines shortly after which the J7 returned to Western Port.
The J3 Submarine was stripped and the hull scuttled in January 1926 as a pier and breakwater off Swan Point, Swan Island, where it had been moored since 1922. It settled almost on top of the wreck of the 961-ton coal hulk S.F. Hersey. Her batteries were later used to power an electric trolley situated at the Mine Depot at Swan Island.
Four subs, J1, J2, J4, and J5, were scuttled in the Victorian Ships' Graveyard. Two were scuttled as breakwaters: J3 near Swan Island, and J7 at Sandringham Yacht Club.
See also Heritage Council Victoria: J-3 Submarine,
Australian National Shipwreck Database: J-3 Submarine,
Royal Australian Navy: HMAS J3,
WW1 J Class Submarines,
WW1 J Class Subs,
Wikipedia: HMS J3, and
Wikipedia: J-class submarine.
Heritage Warning: Any shipwreck or shipwreck relic that is 75 years or older is protected by legislation. Other items of maritime heritage 75 years or older are also protected by legislation. Activities such as digging for bottles, coins or other artefacts that involve the disturbance of archaeological sites may be in breach of the legislation, and penalties may apply. The legislation requires the mandatory reporting to Heritage Victoria as soon as practicable of any archaeological site that is identified. See Maritime heritage. Anyone with information about looting or stolen artefacts should call Heritage Victoria on (03) 7022 6390, or send an email to heritage.victoria@delwp.vic.gov.au.
Wathaurong (Wadda-Warrung) country
Traditional Owners — This dive site is in the traditional Country of the Wathaurong (Wadda-Warrung) people of the Kulin Nation. This truly ancient Country includes the coastline of Port Phillip, from the Werribee River in the north-east, the Bellarine Peninsula, and down to Cape Otway in the south-west. We wish to acknowledge the Wathaurong as Traditional Owners. We pay respect to their Ancestors and their Elders, past, present and emerging. We acknowledge Bunjil the Creator Spirit of this beautiful land, who travels as an eagle, and Waarn, who protects the waterways and travels as a crow, and thank them for continuing to watch over this Country today and beyond.
J3 Swan Island Submarine Location Map
Latitude: 38° 14.643′ S (38.24405° S / 38° 14′ 38.58″ S)
Longitude: 144° 42.183′ E (144.70305° E / 144° 42′ 10.98″ E)
Datum: WGS84 |
Google Map
Added: 2012-07-22 09:00:00 GMT, Last updated: 2022-03-27 16:52:01 GMT
Source: GPS
Nearest Neighbour: S.F. Hersey, 178 m, bearing 216°, SW
J-Class Submarine, 1820 ton.
Built: Dyfed, Wales, 1916.
Scuttled: January 1926.
Bellarine Peninsula, Port Phillip.
Depth: 0 to 8 m.
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DISCLAIMER: No claim is made by The Scuba Doctor as to the accuracy of the dive site coordinates listed here. Should anyone decide to use these GPS marks to locate and dive on a site, they do so entirely at their own risk. Always verify against other sources.
The marks come from numerous sources including commercial operators, independent dive clubs, reference works, and active divers. Some are known to be accurate, while others may not be. Some GPS marks may even have come from maps using the AGD66 datum, and thus may need be converted to the WGS84 datum. To distinguish between the possible accuracy of the dive site marks, we've tried to give each mark a source of GPS, Google Earth, or unknown.
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