Recent research published in the Journal of Refractive Surgery demonstrated promising near and intermediate vision outcomes following implantation of Bausch + Lomb Corporation’s enVista Aspire intraocular lens (IOL) in patients undergoing cataract surgery.
Let’s begin with a look at enVista.
The enVista Aspire is just one of several IOLs included in B+L’s family of enVista hydrophobic acrylic IOLs—see here for a look at them all (and check out research on another enVista IOL, the Envy).
About the brand: The enVista family encompasses both monofocal and toric hydrophobic acrylic IOLs with two key properties—aberration-free optics and distinct lens designs—to enable predictability, stable performance, and visual acuity.
And what sets these lenses apart from other IOL brands?
That would be the incorporation of a few proprietary technologies to ensure they:
- Are scratch-resistant (via TruSight Optic)
- Have reduced edge glare (via SureEdge design)
- Can achieve enhanced optic recovery (via StableFlex technology)
- Can be manipulated for a more secure positioning (via AccuSet Haptics)
Now to the focus of this research: the enVista Aspire.
The enVista Aspire hydrophobic IOL was launched to the U.S. commercial market in October 2023.
- Its indication: For primary implantation in the capsular bag of the eye of patients to visually correct aphakia after cataractous lens removal.
- Also: The lens’s optics enable a range of vision beyond just one focal point—a major difference from conventional spherical monofocal and lower-order aspheric IOLs.
To note: A toric version of this lens is also available with the following indication:
- Primary implantation in the capsular bag of the eye in adult patients for the visual correction of aphakia and corneal astigmatism following the removal of a cataractous lens for improved uncorrected distance vision.
Got it. So explain how the lens works.
According to B+L: The lens (including its toric version) uses an optical modification of the posterior aspheric surface to create a small continuous increase in IOL power within the central 1.5 mm diameter to slightly extend the depth of focus (DOF).
Additionally: In clinical evaluation, the lens has demonstrated high modulation transfer function (HMTF) and contrast through the entire range of focus, from distance to intermediate.
- Importantly, however: Its safety information notes that “clinically meaningful extension of the DOF has not been demonstrated in clinical trials.”
Next up: this study.
This prospective observational study sought to evaluate the enVista Aspire IOL’s refractive outcomes; focus curve; wavefront analysis; and automated refraction.
The participants included 29 patients (29 eyes; mean age: 64.9 ± 16.8 years; 58.6% female) with healthy eyes and normal vision potential.
- Take note: Only one eye from each patient (or just the right eye, if both were eligible) was included in the analysis to avoid potential bias from “inter-eye correlation.”
As for the setup: Patients underwent standard cataract surgery (phacoemulsification) and were implanted with the enVista Aspire IOL.
And what was measured?
Quite a few outcomes, including:
- Monocular uncorrected-distance visual acuity (UDVA)
- Corrected DVA (CDVA)
- Distance-corrected intermediate VA (DCIVA; at 66 cm)
- Distance-corrected VA (DCVA; at 40 cm)
- VA
- Defocus curve
- Wavefront analysis
- Mean refractive prediction error
- Automated and manifest (MRSE) refraction spherical equivalent
Timeframe-wise: Participants were evaluated for these outcome measures at a scheduled postoperative visit between 1 and 3 months
- See here for those parameters and click here for details on how investigators conducted their statistical analysis.
So what were the results?
Brace yourself for a whole lot of data, starting with a postoperative mean CDVA of 20/20 (and 100% eyes achieving 20/25 or better):
- 0.23 logMAR (Snellen equivalent 20/34) at intermediate
- 0.28 logMAR (Snellen equivalent 20/38) at near
The study authors noted that UDVA was also maintained at 0.04 logMAR (Snellen equivalent 20/22), with 93.1% of eyes having Snellen equivalent 20/25 or better.
Go on with these visual acuity outcomes …
Investigators analyzed the VA outcomes of this study with those seen in prior research on other enhanced monofocal IOL designs—such as Johnson & Johnson’s TECNIS Eyhance IOL and Rayner Enhanced Monofocal Vision (EMV) IOL.
- The findings: Comparable outcomes observed in the reported ranges of all three lenses.
Case in point: The mean DCIVA attained for the enVista Aspire was 0.23 logMAR (Snellen equivalent 20/34, with 90% of eyes achieving 20/40 or better), while the ranges for the other two monofocal IOLs were:
- Tecnis Eyehance: 0.17 to 0.23 logMAR
- Rayner EMV: 0.17 to 0.28 logMAR
Was this also true for the mean DCNVA?
Comparing this to the previously reported range identified for the TECNIS Eyhance—pretty much:
- enVista Aspire: 0.23 logMAR
- Tecnis Eyehance: 0.25 to 0.50 logMAR
Further: The enVista Aspire demonstrated a Snellen equivalent of 20/38, with 83% of eyes achieving 20/40 or better.
Still sticking with these VA outcomes … how did the defocus curve fare?
The enVista Aspire demonstrated an estimated 1.50 diopter (D) of continuous DOF for a VA of 0.2 logMAR or better.
- The study authors’ insights on this: “These sustained visual acuity outcomes through different defocus values may be related to the continuous change in power provided by the IOL's optic design.”
And, keeping in mind that the enVista Aspire’s DOF is due to the curvature changes on the IOL’s posterior surface, the data indicated that:
- It did not increase the corneal spherical aberration
- Excellent visual outcomes at the intermediate provided by the enVista Aspire were likely due to the IOL’s higher-order aspheric coefficients of its intermediate-optimized IOL optic.
See here for a more detailed rundown on this.
What’s next?
As part of wavefront analysis, investigators used MTF (see how) to evaluate the IOL’s optical performance (and assessed MTF separately for total, internal, and corneal aberrations).
- In general: MTV values 0.5 or above are typically indicative of good quality optical performance.
In this study: These values were > 0.50 when measured at 2-mm and natural pupil apertures—notably higher than previous research reportings of ∼0.30 at a 3-mm pupil for normal adults (aged 60-70).
- What this suggests for the enVista Aspire: A “good optical performance” following cataract surgery (with excellent image contrast), according to the study authors.
Anything else for this analysis?
Investigators also confirmed low postoperative aberrations, with the measured spherical aberrations finding: 0.08 µm at 4.5 mm pupil.
Let’s analyze postoperative MRSE.
The mean MRSE was reportedly “close to emmetropia (0.02 ± 0.29 D),” with 96.6% of eyes within ±0.50 D.
As for automated refraction: This was within ±0.25 D of the subjective refraction.
So! All in all, what were the takeaways from this research?
The study authors concluded that enVista Aspire IOL implantation demonstrated “useful near and intermediate vision” while also ensuring:
- “Excellent” distance acuity maintenance
- Minimal postoperative spherical aberration (based on wavefront analysis)
- An automated refraction near emmetropia (based on wavefront analysis)