Bausch + Lomb’s latest version of the enVista monofocal recently became available to Australian and New Zealand surgeons along with a new pre-loaded delivery system. Early adopters discuss making it a go-to IOL and how it’s offering increased depth-of-field in many patients.
The enVista family of intraocular lenses (IOL) has carved out a reputation among cataract surgeons for its robust, glistening-free material, visual clarity and predictable outcomes.
But as ophthalmologists demand greater efficiencies in the operating theatre and ease-of-use with intricate toric implantation, Bausch + Lomb (B+L) has been keen to improve the unfolding time of the hydrophobic acrylic lens that previously took between one and 2.5 minutes.
With this in mind, the company’s engineers have modified the enVista platform to remove what many surgeons saw as its only major drawback by changing the ratios of two polymers that enable the lens to unfold significantly faster – which some surgeons report to take about 20 seconds*.
The next-generation enVista has been available as a monofocal in the US (where it is called MX60E) since 2018 and was released in Australia this year in April. The toric version was launched in the US in 2019 and will arrive here soon.
What’s even more appetising is that B+L has developed a new pre-loaded delivery system for enVista called SimplifEYE that provides a more user-friendly experience compared with its original BLIS inserter. Locally, the new IOL and injector are called the MXPLC or enVista preloaded with SimplifEYE delivery system.
In recent years in the US, enVista has also been earning a reputation as a “monofocal-plus” among surgeons, with a growing body of evidence demonstrating intermediate and near vision in selected patients.
Dr Dee Stephenson is one of those surgeons. She has a boutique private practice in Florida in the US and was the world’s first ophthalmologist to implant the latest enVista monofocal in 2017. She says it has maintained the original qualities that made it a go-to monofocal and toric for her many years before, while bringing even greater benefits.
“People say to me I’m not using that lens because it took forever to open, but now I’ve told a lot of those naysayers in my country to try it and they are really happy with how it’s performing,” she says.
“Another great feature is how it sits in the eye; it has big broad haptics that cover 110 degrees of the capsular bag and almost acts like a capsular tension ring. So, it sits really well with very little rotation – less than five degrees, I believe. That stability is especially important in the toric form.”
A traditional enVista attribute has been its material that is said to be 25 times harder than traditional hydrophobic acrylic lenses, reducing the likelihood of scratches and abrasions.
Although it now opens faster, Stephenson says Australian surgeons can expect it to remain well-controlled, especially with the new delivery system.
“I like this lens because the outcomes are so predictable, but where it really shines is that 85% of my patients are 20/40 (6/12) vision or better at intermediate uncorrected and then I’m getting another 30% who are J1 (Jaeger 1) or better,” she says.
“Even if it is not a premium lens, it’s what you would call a toric-plus or monofocal-plus because a lot of these people have great intermediate vision; it’s very functional, especially in dim lighting, so it has been a win-win.”
Exploiting positive corneal spherical abberation
Fellow Californian surgeon Dr Mitchell Shultz has also been an early adopter of the enVista technology. He says the aberration-free and aspheric lens offers edge-to-edge uniform power which makes a difference in cases where patients aren’t looking through the lens centre or with complications like zonulopathy.
“In cases where the lenses aren’t necessarily centred, or later they decentre, patients never lose quality of vision with this material,” he says.
Shultz was the first to quantify the intermediate and near vision benefits after discovering unexpected results with the original enVista around eight years ago. It was unlike anything he had experienced on another platform.
“I wasn’t the only one experiencing it, but it wasn’t until I got the Tracey iTrace ray tracing technology that we were able to find some objective markers to predict which patients would have enhanced depth-of-field,” he says.
“I started to speak about it on B+L’s behalf in 2015 at which point other people started to replicate my results. Many colleagues would agree that uniformly across the platform you can expect 25% of patients to have pretty good J2 near vision and something like 70-80% J3-J4 intermediate vision, so they can function a lot of the time without glasses.”
Through corneal analysis, Shultz has elucidated that the enhanced depth-of-field is not pupil-dependant but is to do with pre-existing corneal spherical aberration.
“It comes down to patients in the +0.25 to +0.31 μm positive corneal spherical aberration range that get, on average, the most enhanced depth-of- field, so it’s not necessarily the lens that’s causing it, but it’s giving the patient the best chance of depth-of-field based on their corneal aberrations.”
While enVista’s key features ensure its suitability to a broad range of patients, Stephenson says it’s useful in post-refractive patients seeking outcomes similar to their laser surgery, despite having a poor ocular surface, as well as people ineligible for multifocals or EDOFs, or who don’t want photic phenomena.
“This lens provides some leeway. Even if their vision isn’t 20/20, they are 20/30 and they see at near and intermediate and have got a quality of vision,” she says. “We all talk about 20/20 vision or better, but we forget it’s the quality of vision that’s so important; people don’t mind having to put on a pair of readers in dim light, but boy do they mind if their quality of vision at distance is not good.
“In my experience, the lens is also good for patients who have epiretinal membranes or mild macular degeneration where they may not have been 20/20 to begin with, but it still gives them really great quality. They have an added spring in their step because they are seeing better than expected after being disappointed they couldn’t have a multifocal or EDOF.”
Aside from its fenestrated haptics and controlled unfolding, the new enVista offers a continuous 360-degree square edge design to minimise posterior capsular opacification (PCO) development. The sharp edge has been shown to reduce PCO compared to round edge designs, as demonstrated in studies.
Lower PCO rates was the one of the main reasons Australian surgeon Dr Joseph San Laureano, a principle at Melbourne Eye Centre and senior consultant at The Royal Victorian Eye and Ear Hospital, made enVista a lens of choice several years ago.
He was one of 11 Australian surgeons who completed a pre-launch evaluation of the enVista preloaded with SimplifEYE delivery system at the end of last year.
“When I went back to the original enVista many years ago it did solve the PCO problem I was having with other lenses, but it was inconvenient because they were stiff to use,” he says.
“If you’ve got a toric that’s totally curled up on itself, you just can’t align it and that’s disconcerting. So, having it unfold in what feels like an instant is an enormous move forward and will really pay dividends when the toric comes out.”
With his limited use, the biggest difference San Laureano has noticed is the enhanced depth-of-field. Its association with pre-existing positive spherical aberration present in the aging cornea is a concept he believes will gain in popularity like measuring posterior corneal astigmatism.
“And now posterior astigmatism has become standard. The lenses are increasingly coming out with various ways of increasing depth-of-field and spherical aberration is probably the next big thing.”
10-fold improved loading experience
B+L’s new SimplifEYE delivery system, developed exclusively for the enVista, is also driving greater efficiencies and safer practices in the theatre.
It allows the surgeon to deliver the lens through incisions as small as 2.2mm, with the enclosed cartridge holding an untouched IOL to ensure proper positioning and reducing the risk of damage. The see- through device also has a bevelled tip for consistent lens folding to afford surgeons reproducible and reliable delivery into the capsular bag.
As a presbyope, San Laureano says he previously loaded the enVista under the microscope which could be an intricate process. If not done correctly, it could jam or the haptic could leave an imprint or stick to the optic, making for a fiddly procedure while the lens is in the eye.
“But all of this is gone now … it’s a 10-fold better experience for loading,” he says.
Stephenson says the surgeon can put the bevel down and screw it directly into the capsular bag, with the trailing haptic also in the bag.
“I think B+L is trying to make this universal where people don’t have to touch the implant, and having a no-fail, safe way to insert it into the eye,” she says.
“The SimplifEYE delivery system has been a great addition with a small learning curve. This empowers the operating room staff and, with just a few practise tries, they can load the lens with real confidence. All of these processes take time to learn and the more efficient you are the less stress you will have. This makes the operating room experience better for everyone.”
*May vary with surgeon technique.