Out of the ordinary prescriptions have, and always will be in demand for a small number of patients. Knowing what’s possible and where to turn when you have a patient with a high prescription and/or other special vision needs is essential to achieve the best outcome with minimal fuss.
We spoke to the lens labs to find out what they have to offer.
Depending on your patient demographic, you may not need to arrange specialty prescriptions very often, or, they may come through on an almost daily basis.
Complex prescriptions will be required for a number of reasons – the myopia pandemic is leading to growing numbers of patients with high myopia; contact lens patients with complex and high prescriptions need backup spectacles for emergencies, to give their eyes a break and during allergy season, fires, droughts, illness, air travel and so on. There are also a variety of professions, sports, and hobbies that may necessitate complex prescriptions, such as wraparound sunglasses for cycling, goggles for swimming, and masks for diving. Demand for goggles and masks is being driven partly by a growing awareness of the need to avoid mixing water and contact lenses.
around seven million people worldwide – approximately 29,000 of them in Australia and New Zealand – have extreme ametropia that cannot be corrected by ordinary lenses
Last century, before intraocular lenses became the standard of care for cataract surgery, we were faced with many aphakes who required spectacle lenses in the +15D to +20D range, sometimes higher. Back then, Essilor was well known for its problem-solving single vision and bifocal Omega aspheric lenses.
Essilor reports that around seven million people worldwide – approximately 29,000 of them in Australia and New Zealand – have extreme ametropia that cannot be corrected by ordinary lenses.
To help meet this need, Essilor’s ‘Special Lens Laboratory’, located in eastern France, has two offers; the Essilor Exceptio range, which is an extensive pre-defined range with spheres from -40D to + 30D, cylinders >6.50D, and prisms above six prism dioptres. The range includes lenses such as the SV Omega and Varilux Omega; aspheric products and an ‘on-demand’ range, which creates unique custom-made solutions for particular cases.
At the Special Lens Lab, ninety expert optical craftsmen use their skills to create the unique custom-made solutions. Some record examples are a -108D lens for a photographer in Slovakia, a 35D prism lens for a wearer in the Czech Republic, and more recently, a +78D lens for a patient from the NSW Central Coast. Essilor Australia’s Special Lens Service – launched in 2017 – was the recipient of the ODMA ‘Excellence in Lens Design’ award.
THE INVISIBLE BIFOCAL
Other major lens producers have also earned a reputation for providing solutions to meet complex visual needs.
Over sixty years ago, Irving Rips created an ‘invisible line’ bifocal in his Los Angles garage. This led to the formation of Younger Optics – so named because the new invisible bifocal would make the wearer look younger. Today, as one of the world’s largest privately-held ophthalmic lens manufacturers, Younger provides solutions to meet the needs of some unique cases, like for instance, presbyopic mechanics who struggle to see what they are working on while under a car or in a weird position. The solution? Occupational flat top 28DD trifocal lenses that provide intermediate or full near additions in the top segment.
Another challenge they’ve met is to meet the needs of patients with debilitating diplopia due to III, IV and VI nerve palsies, sometimes caused by a severe stroke. Short of covering one eye, these patients may look for relief with, for example, two prism base in each eye for reading, however they do not tolerate prism at distance and two pairs of spectacles are not always practical. Younger Optics offers a reverse slab off prism flat top 28 bifocal to help solve such problems. A slab off bifocal allows for prism to be applied for near, without requiring it in the distance.
THE REWARDS OF OFFERING SPECIALTY LENSES
There are also a few home-grown favourites, like CR Surfacing and Rx Safety, that take great delight in helping people with complex Rx needs by providing novel solutions.
CR Surfacing manufactures a range of specialty lenses in its state-of-the-art laboratory in Melbourne.
“Owing to our independence and innovations, we can manufacture lenses outside of the standard power range, reaching as high as +12.00 to -20.00 combined power,” explained Adam Fletcher, Managing Director of CR Surfacing. “Our edging machine can cut lenses for the craziest frames out there, even if it is the shape of a kangaroo,” he added.
CR Surfacing is the exclusive supplier of Shaw Lenses in Australia, used for treating symptoms of aniseikonia. Additionally the lab has a portfolio of polytrauma filters, which are of value to optometrists with a special interest in neuro-optics.
“Our most popular therapeutic tint is the renowned FL41, that offers relief from migraine and other symptoms associated with photophobia,” said Mr Fletcher adding that CR Surfacing’s business development managers and dedicated specials departments are always ready to answer any technical questions that eye care professionals may have.
There’s little that’s more rewarding than witnessing the difference we can make to a person’s life by finding a solution to a complex or unusual challenge. For Trent McInerney, director of Rx Safety, an all-time favourite was helping out a six-year old girl.
A fortnight later, the little girl’s mother rang me in tears of gratitude. Definitely my most satisfying job!
“The little girl’s eyesight was way too poor for most sports, so her mum thought she would be able to join a swimming club – all she needed was Rx swimming goggles. They’d been to a couple of chain stores and been told that swimming goggles in her Rx could not be made,” he explained.
Trent told her that Rx Specialty – a division of Rx Safety – would gladly help. “When I received the huge minus script, I wondered just what I had gotten myself into, however we figured it out and duly sent the goggles off. A fortnight later, the little girl’s mother rang me in tears of gratitude. Definitely my most satisfying job! Since then we have made swimming goggles from -22D to +23D.”
In another example of something out of left wing, Trent received a call from a Civil Aviation Safety Authority (CASA) optometrist, who was trying to get 3D Rx spectacles made for the military. He’d dealt with a number of laboratories, with no success.
“Rx Safety worked out a precise method and worked with the CASA optometrist to get accreditation with the Royal Australian Air Force (RAAF) and North Atlantic Treaty Organization (NATO),” Mr McInerney said. Rx Safety now makes 3D spectacles for the CASA optometrist to supply to RAAF crew for in-flight air refuelling and is accredited to make the same for NATO.
Rodenstock manufactures its premium digitally surfaced lenses across a broad power range in a variety of refractive index materials. The company also offers the Manufaktur range, covering “lenses for extreme prescriptions or for medical purposes” in plastic as well as glass. Rodenstock’s Ardis trifocals are made up of fused segments, enabling any combination of distance, intermediate and near, with a different prism in each segment, as needed. Biconcave, biconvex, plano concave and plano convex lenses are available for collectibles such as monocles and lorgnettes and specialty use such as dive masks.
Nicola Peaper, National Sales and Professional Services Manager at Rodenstock Australia says demand for bespoke prescriptions is increasing.
“Bespoke lenses have become more difficult to source due to a declining skills base,” said Ms Peaper. “It is therefore valuable to be able to take advantage of the technical expertise and craftsmanship still available at Rodenstock. While the demand for spectacle lenses for aphakic patients is not as high now, the requests we receive for extreme prescriptions seems to grow on a daily basis. It is rewarding to be able to satisfy the demands of clients who may need near vision at the ‘top and bottom’ of their lens and distance in the middle, or other unlikely combinations.”
Similarly, Zeiss offers a fantastic range of special prescriptions and is the only lab to offer a 1.9 index glass material. Overall 1.8 index glass has largely been replaced by 1.74 plastic materials which, through aspheric design options, can often present a thinner lens profile than a 1.8 glass lens, with dramatically improved safety.
Shamir Australia offers a full range of lens products from mainstream lenses to any speciality lenses, which includes high prisms and high powers. Shamir Tribrid, exclusive to Shamir, is a hybrid material that combines the best attributes of Hi-Index lenses with comfort, strength, and durability. This lens material is excellent for rimless, nylon, inline fits, and patients who want lightweight eyewear. Shamir Tribrid has all the benefits of 1.6 index with a much higher safety rating.
Shamir Australia’s speciality lenses are manufactured in Shamir’s Brisbane based Australian Made laboratory, which employs over 110 Australian workers. The laboratory is equipped with the world’s best cutting edge digital equipment.
Frame selection is critical for complex high prescriptions. A shallow frame depth is ideal when splitting vertical prisms between eyes while keeping the edge thickness under control. For a high plus or minus Rx, the ideal is to keep the eye size as small as practically possible. Similarly, with high astigmatism we can select, for example, a shallow vertical depth frame for an axis 180 cyl and vice versa. Large fashion sunglasses or an aviator shape may not be ideal for some prescriptions, including high Rx progressives and certain cases of oblique astigmatism.
In general, small eye sizes keep overall mass and thickness down, as well as improving comfort and the cosmetic outcome, as do anti-reflection coatings.
Other aspects of frame design that can add to a patient’s comfort include a special nose bridge and properly fitted and adjustable temples, especially for thick and heavy high prescriptions. Correct fit and centration are also essential for the ever-expanding range of myopia controlling spectacle lenses, which have very specific setup needs.
So, there you have it. You can work miracles when armed with the correct knowledge and products. Don’t hesitate to contact your lab to discuss power ranges available and how best to meet the special needs of this small but important group of patients. You’ll also find plenty of useful information on their websites.