Perth ophthalmologist A/Prof ROB PAUL explains why the latest diffractive intraocular lens design from Bausch + Lomb, enVista Envy, has him reconsidering his approach when patients come seeking spectacle independence.
At a time when all the buzz in cataract surgery is centred on so-called extended depth of focus (EDOF) intraocular lenses (IOLs), Western Australian ophthalmologist A/Prof Rob Paul has made a lens with a diffractive anterior surface his new go-to in presbyopia correction.
While the ability to see from near to far has been the major drawcard of diffractive designs, the not-fully-resolved issue of glare, haloes and starbursts – as EDOFs improve – has seen some recent favouritism towards the latter category.
But the new enVista Envy hydrophobic acrylic IOL from Bausch + Lomb has A/Prof Paul rethinking the way he goes about cataract refractive surgery. The “full range of vision” lens just became available to Australian surgeons, with A/Prof Paul having implanted 12 at the time of writing – the most of any surgeon in Australia.
He’s always treated new multifocal IOLs (although B+L doesn’t refer to enVista Envy this way) with caution. But was surprised to see patients with this IOL read small print, along with 6/6 to 6/9 distance vision and little to no visual disturbances one day post-operatively. The results have also been backed up in one-month follow-ups.
“It would definitely be my first choice lens for anyone wanting presbyopia correction at this point in time,” he says.
“Often ophthalmologists in the general sphere want a lens that’s not going to cause any issues for them later down the line – and that’s where this lens comes to the fore.”
Based on the enVista platform, B+L has made improvements in the optical design in developing the enVista Envy.
The “enviable” dysphotopsia tolerance is a major selling point. Four-to-six-month data out of the US involving more than 300 people found 88% had little to no bothersomeness with glare, 80% with haloes and 91% with starbursts. The numbers were even better in a Canadian study: 96%, 88% and 94%, respectively.1,2
For a competing trifocal in a separate study, those numbers were 72-73%.
In terms of the range of vision, the lens offers 4.00 D of continuous vision,4 with the US studying showing 79% of patients achieved N4 (near), 91% 6/7.5 (intermediate) and 85% 6/6 (distance) – all in bilateral photopic conditions.1
The Canada study demonstrated the near-vision benefits, with 91% reporting little to no difficulty reading a mobile screen and 95% when reading a computer screen.2
“As the technology has evolved, my general feeling is most Australian patients, whilst they want spectacle independence, maintaining distance vision is very important, as well as minimising anything like glare and haloes – we want it all,” A/Prof Paul says.
“This is where a lens like this appeals, because it gives the full range of vision and it’s got a very high tolerance to dysphotopsia – it surprised me.”
Some crucial design has enabled this, and A/Prof Paul has been impressed with the results in patients implanted bilaterally with enVista Envy. Others have received an off-label mix of enVista Envy in one eye, with an EDOF implanted in the dominant eye.
“I performed my own glare and haloes test on patients with a pinpoint source of light, and we actually saw greater starbursts in the EDOF design – there was no dysphotopsia symptoms that we could see with the enVista Envy one month post-op.
“I am waiting for more data to see if bilaterally implanted patients are getting any significant glare and haloes, and if it continues as I predict, I’ll routinely implant it bilaterally.”
A/Prof Paul says a common fear preventing some ophthalmologists from fully embracing diffractive designs is the residual refractive error causing a wax-like distance vision. But he hasn’t seen that with enVista Envy.
“When you get better reading, you expect a reduction in distance vision, but I’m not seeing that. In addition to being 6/6 to 6/9 for distance vision, my patients have been N5 to N6 for up close, monocular,” he says.
“But the shocking finding for me has been the minimal glare and haloes, and after speaking to the company I’ve understood why; it’s due to their proprietary technology which is akin to graduated steps on the diffractive rings, lessening the amount of light scattering.”
This propriety technology is part of a new optical design that B+L calls ActivSync. It is designed to enhance image contrast when patients require it most, evenly distributing light in photopic (well-lit) conditions and prioritising distance in mesopic (low light) conditions.5
“When you look at the defocus curve it’s a very flat line, from about zero to -3.00 D, so it doesn’t deviate much like multifocal lenses might,” Dr Paul says.
“That’s part of the reason why the vision is quite good for distance. And with the ActivSync optics, this leads to an even energy distribution of light. So in dimmer conditions, when the pupil is greater than 4 mm, it prioritises distance.
“That’s one of the special features of this lens, it’s why the distance vision is still quite good, even in the low contrast conditions.”1-3, 5
New depths in astigmatism correction
Another drawcard for Australian surgeons – who have a particularly high toric implantation rate6 with estimates ranging from 30% to more than 50% – is the new features to address corneal astigmatism.
B+L has introduced Low-Cyl technology, helping surgeons broaden the treatable astigmatism range to as low as 0.9 D at the IOL plane.7 It’s the first and only full range of vision toric platform that can offer this, according to the company.
It’s important considering 74% of cataract patients have less than 1.25 D of corneal astigmatism.8
At the other end of the spectrum, the maximum available cylinder on enVista Envy is -5.75 D at the IOL plane, and it’s reported to be the only toric platform that treats in half-step cylinders (up to 3.50 D at IOL plane).
“In my experience, and the studies have shown, anything above 0.7 D is worth treating with a toric IOL, and most of my enVista Envy patients have had some sort of toric correction. It leads to less aberrations, better distance vision, and certainly ensures the lens is better tolerated overall,” says A/Prof Paul.
He adds that a longstanding benefit of the enVista platform is its rotational stability and toric alignment, with 110-degrees of capsular bag contact, and 300% more radial compression force than traditional hydrophobic IOLs.10
All up, 94.4% of eyes had less than five-degrees of rotation, which B+L says equates to proven rotational stability through 180 days post operatively.8
The rotational stability is aided by fenestrated holes in the enVista Envy Toric, simplifying lens manipulation during surgery, allowing both clockwise and counterclockwise positioning in the capsular bag.11
“I’ve also found it leads to less optic stress on the capsular bag,” A/Prof Paul adds.
One of the big reasons A/Prof Paul has used the enVista platform traditionally is its glistening-free material, the only IOL of its kind with this FDA indication.
Now, enVista Envy features glistening-free material with improved scratch resistance and 25 times the hardness of traditional hydrophobic IOLs.12
At the same time, one aspect B+L has been keen to improve is the unfolding time of the enVista, which it has achieved in recent years with a change to the material.
It’s something A/Prof Paul can attest to.
“I’ve noticed the change in the fabric of the actual lens – and have had no problems with the unfolding time,” he says.
B+L’s SureEdge design is also an appealing feature, helping the surgeon against posterior capsular opacification.14, 15
“The fact it’s a hydrophobic IOL is another huge benefit for me because a lot of the other lenses out there that I would deem competitors are hydrophilic that have the potential to opacify over time,” he says.
“All in all, I’ve been pleasantly surprised, especially in the way it has performed offering excellent near vision results while few, if any, dysphotopsia symptoms in the cases I’ve performed so far.”
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References
1. Data on File. enVista Envy US Clinical Study, conducted with model MX60EF
2. Data on File. enVista Envy Canadian Clinical Study, conducted with modelMX60EFH
3. Alcon AcrySof PanOptix Clinical Study.
4. enVista Envy US Clinical Study, n=53 patients reported outcomes 4–6-month post-op, bilateral
5. Data on File, Bausch+Lomb.
6. Goggin M. Toric intraocular lenses: evidence-based use. Clin Exp Ophthalmol. 2022; 50: 481-489.
7. enVista Toric Directions for Use, Bausch & Lomb.
8. Data on File. enVista Toric MX60ET US Clinical Study
9. enVista Envy Toric Directions for Use, Bausch & Lomb.
10. Bozukova D, Pagnoulle C, Jérôme C. Biomechanical and optical properties of 2 new hydrophobic platforms for intraocular lenses. J Cataract Refract Surg. 2013;39(9):1404-1414.
11. Wiley WF. Rotational stability of aberration neutral hydrophobic toric IOL with enhanced delivery characteristics. Presented at: ASCRS Annual Meeting; April 22-26, 2022; Washington, D.C.
12. Heiner P, Ligabue E, Fan A and Lam D. Safety and effectiveness of a singlepiece hydrophobic acrylic intraocular lens (enVista®) – results of a European and Asian-Pacific study. Clinical Ophthalmology 2014:8 629-635
13. https://www.insightnews.com.au/rethinking-whats-possible-with-the-envista-iol/
14. enVista Envy Directions for Use, Bausch & Lomb.
15. Pai HV, Pathan A, Kamath YS. A comparison of posterior capsular opacification after implantation of three different hydrophobic square edge intraocular lenses. Indian J Ophthalmol. 2019;67(9):1424-1427. doi: 10.4103/ijo.IJO_219_19.
