ASCRS News: EyeWorld Journal Club
September 2022

by Lisa Koenig, MD, Charles Cole, MD, Brigette Cole, MD, Grace Sun, MD, and the Weill Cornell Medicine ophthalmology residents

Among eyes undergoing cataract surgery, corneal astigmatism is common. In a systematic review of 31 studies published in 2018, nearly half (47%) of eyes undergoing cataract extraction were found to have at least 1 D of corneal astigmatism.¹ Postoperative residual uncorrected astigmatism carries an economic burden primarily in the need for spectacles, estimated to be several thousand dollars over a lifetime. To address this need, toric IOLs were developed. Approved by the FDA in 1998, toric lenses originally had a plate-haptic design, and were subsequently updated to enhance rotational stability; modern-day lenses have an open loop haptic design. When compared to non-toric IOLs, even in situations where limbal relaxing incisions are used, toric lenses have been shown to deliver enhanced visual outcomes, quality of life, and spectacle independence.² Critically, to optimize postoperative visual outcomes, toric lenses must not only be placed at the proper axis intraoperatively but also must remain well-aligned postoperatively. Modern-day IOLs are associated with a <3% rate of second surgeries for realignment.³ To date, these data regarding rates of surgical realignment come from controlled trials or single-center series. In this retrospective study, Kramer et al. used the Intelligent Research in Sight (IRIS) Registry to reflect real- world experience of reoperation rates for IOL realignment in eyes implanted with the AcrySof toric lens (Alcon) versus the TECNIS toric lens (Johnson & Johnson Vision).

Methods

The IRIS Registry collates data from the electronic medical records of U.S. ophthalmologists. In 2016, it included data from 7,400 ophthalmologists over 2,300 practices representing approximately 40% of U.S. ophthalmologists.^3,4 The authors used ICD-10 and CPT codes to identify adults over age 45 with age-related cataracts who had undergone cataract extraction between January 1, 2016, and December 31, 2017. Inclusion criteria stipulated that patients must have at least two postoperative visits within 180 days of surgery. Patients were excluded based on a number of preoperative complicating ocular diagnoses and if any CPT codes indicating intraoperative surgical complications were present. The authors then identified cases that were associated with the CPT code indicating need for surgical repositioning within the first year after surgery. Their primary interest was the repositioning rate of the AcrySof toric IOL compared to the TECNIS toric IOL. Finally, the authors used logistic regression to identify risk factors for repositioning. An independent partner, Verana Health, was used to extract and statistically analyze the data.

Summary of results

In total, 11,012 eyes met inclusion criteria and were implanted with a toric lens over this period: 4,530 with a multifocal toric IOL and 6,482 with a monofocal toric IOL. However, given the imbalance in frequency of AcrySof and TECNIS among the multifocal toric eyes (98.5% were implanted with TECNIS), the authors focused on the monofocal toric eyes only, which had a more balanced distribution between AcrySof (4,469, 68.9%) and TECNIS (2,013, 31.1%) lenses. Overall, the mean age was 70 years, and the majority were women (60.3%) and white (88.2%). Importantly, these demographic characteristics did not differ significantly between the AcrySof- and TECNIS-implanted eyes.  

Within 1 year of surgery, 1.3% of eyes underwent a second surgery to reposition the lens, which was significantly more frequent in the TECNIS group (3.1%) versus the AcrySof group (0.6%, P<0.0001). Logistic regression identified that the odds ratio for repositioning was 5.57 (3.48–8.92) for the TECNIS lens relative to the AcrySof lens. Further, they found that younger age was a significant risk factor for IOL repositioning with an odds ratio of 0.76 (0.67–0.86) for every 5-year increase in age, suggesting less repositioning among older patients. No other significant risk factors were identified (including sex, race, or region of country where the surgery was performed).

Discussion

The authors concluded, using IRIS Registry data, that second surgery for IOL realignment was significantly more frequent in eyes implanted with TECNIS monofocal toric IOLs as compared to those implanted with AcrySof monofocal toric IOLs. For both lenses, they found higher rates of surgical repositioning as compared to the registration trials (3.1% versus 2.3% for the TECNIS and 0.6% versus 0.4% for the AcrySof). For context, this difference between AcrySof and TECNIS in terms of frequency of second surgeries for realignment has been demonstrated before; prior studies have shown greater degrees of misalignment from the intended astigmatic axis associated with TECNIS versus AcrySof lenses and have shown greater frequency of realignment operations in TECNIS-implanted eyes versus AcrySof-implanted eyes.^5,6

Beyond TECNIS as a risk factor for realignment, this study also identified younger age as a significant risk factor. The authors posit several hypotheses to explain why this might be: (1) younger patients may be more visually demanding and therefore less tolerant of misalignment, (2) greater activity in the immediate postoperative period may be a cause for postoperative rotation in younger patients, (3) an unspecified difference in the composition of the capsule, or (4) younger patients have more with-the-rule astigmatism and therefore have the toric placed vertically.

The main differentiating factor of this article compared to prior studies with similar conclusions is its use of real-world data from the IRIS Registry, purportedly better reflecting the actual experience of surgeons of a variety of experience levels and practice settings as compared to controlled trial conditions. Several limitations are also discussed. First, eyes were identified using a CPT code associated with surgical IOL realignment, though they acknowledged that a lens may need realignment for reasons other than astigmatic axis rotation (though the authors pointed out that the latter is responsible for most surgical realignment cases in toric IOLs). Other limitations are inherent to the nature of this being a retrospective database study, namely that factors like method of intraoperative axis alignment and pre- and postoperative measurements were not available to the authors. Further, there was no standard for what requires surgical realignment, which was instead pursued based on mutual agreement by surgeon and patient that it would enhance visual outcomes.

During the Journal Club discussion, the strengths and limitations of this work were weighed. Regarding the limitations, it was discussed that many, if not all, of the posited weaknesses should apply equally to both groups (i.e., AcrySof and TECNIS). These suggested weaknesses therefore should not detract from the validity of the study, unless there is an inherent difference in the type of surgeon (e.g., experience or skill level) who implants the AcrySof lens as compared to the TECNIS lens, which we agreed was unlikely. A potential weakness that was not mentioned by the authors but was raised by our panelists was the potential for conflict of interest given the financial relationship between Alcon and the study’s authorship.

Regarding younger age as a risk factor for realignment, our panelists hypothesized that perhaps surgeons have a lower threshold to take younger patients back to the operating room given that they are, on average, a healthier population better able to withstand anesthesia and a second surgery. 

Finally, in terms of future directions, given that the TECNIS lens in the study had already been redesigned at the close of the study, our group was particularly interested in future studies comparing the newly modified TECNIS II lens with the AcrySof lens. The new generation of TECNIS toric lenses are designed to enhance rotational stability to address the very issue discussed herein.

Conclusions

Proper astigmatic axis alignment is critical for the visual outcomes of patients implanted with toric IOLs. The rate of surgical realignment of monofocal toric IOLs was compared using the real-world data of the IRIS Registry, confirming prior reports of greater frequency of realignment associated with the TECNIS monofocal toric IOL as compared to the AcrySof monofocal toric IOL. 

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Real-world incidence of monofocal toric intraocular lens repositioning: analysis of the American Academy of Ophthalmology IRIS Registry

Kramer BA, et al.
J Cataract Refract Surg. 2022;48:298–303 

• Purpose: To determine the 12-month incidence of reoperation to realign 2 commercially available types of implanted monofocal toric acrylic intraocular lenses (IOLs)
• Setting: American Academy of Ophthalmology IRIS (Intelligent Research in Sight) Registry
• Design: Registry retrospective study
• Methods: Eyes that underwent cataract extraction and were implanted with a TECNIS (Johnson & Johnson Vision) or AcrySof (Alcon) monofocal toric IOL in 2016 and 2017 were identified. The rate of reoperation for IOL realignment (Current Procedural Terminology code 66825) within 365 days of implantation was determined for each IOL group. Risk factors for repositioning were evaluated using logistic regression modeling.
• Results: A total of 6,482 eyes were implanted with a monofocal toric IOL, including 2,013 (31.06%) with a TECNIS and 4,469 (68.94%) with an AcrySof IOL. During the first postoperative year, 87 (1.3%) eyes underwent surgical IOL repositioning. The incidence of repositioning was significantly higher (P<.0001) for TECNIS-implanted (3.1%, 62/2013) than for AcrySof-implanted (0.6%, 25/4469) eyes (odds ratio [OR] 5.6; 95% CI, 3.5–8.9). Younger age (OR 0.76; 95% CI, 0.67–0.86 per 5-year increase) was associated with a higher risk for IOL repositioning.
• Conclusion: Real-world analysis of U.S. patients in the IRIS Registry revealed that the rate of surgical IOL repositioning was 5 times higher in eyes implanted with TECNIS than with AcrySof monofocal toric IOLs for astigmatic correction at the time of cataract surgery. These findings should be considered when selecting a toric IOL for correction of astigmatism in cataract patients, particularly in younger patients with a higher risk for misalignment requiring repositioning.

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References

1. Anderson DF, et al. Global prevalence and economic and humanistic burden of astigmatism in cataract patients: a systematic literature review. Clin Ophthalmol. 2018;12:439–452. 
2. Kessel L, et al. Toric intraocular lenses in the correction of astigmatism during cataract surgery: a systematic review and meta-analysis. Ophthalmology. 2016;123:275–286. 
3. Visser N, et al. Toric intraocular lenses: historical overview, patient selection, IOL calculation, surgical techniques, clinical outcomes, and complications. J Cataract Refract Surg. 2013;39:624–637. 
4. Dang S, et al. Estimating patient demand for ophthalmologists in the United States using Google Trends. Invest Ophthalmol Vis Sci. 2021;62:1724.
5. Oshika T, et al. Comparison of incidence of repositioning surgery to correct misalignment with three toric intraocular lenses. Eur J Ophthalmol. 2020;30:680–684. 
6. Lee BS, Chang DF. Comparison of the rotational stability of two toric intraocular lenses in 1273 consecutive eyes. Ophthalmology. 2018;125:1325–1331.

Contact 

Koenig: lrk2002@nyp.org
Sun: grs2003@med.cornell.edu