March 2020

CATARACT

Research Highlight
Traditional vs. modern techniques in managing astigmatism


by Maxine Lipner Contributing Writer

When correcting astigmatism, what’s better: using the standard-of-care, manual approach or doing so with the aid of an image-guided system and intraoperative aberrometer? In a study,1 investigators found that both approaches provided comparable results, according to Kerry Solomon, MD.
Dr. Solomon viewed the study as an opportunity to answer questions he had been wondering about, including whether one technique is superior to the other, as well as what this means for practitioners without image guidance, aberrometry, or femtosecond lasers. “For those who don’t have this equipment available, should they be rushing out to buy it?” Dr. Solomon said.

Comparing outcomes

In this prospective case series, cataract patients with lower amounts of astigmatism were randomized to receive either limbal relaxing or arcuate incisions using a femtosecond laser. If patients needed a toric lens, manual marking or femtosecond laser, image guidance (VERION, Alcon), and intraoperative aberrometry (ORA with VerifEye+, Alcon) was used.
Investigators determined that there was no statistically significant difference in mean spherical equivalent refraction between the groups. “We found that using traditional methods of treating astigmatism was as effective as using some of the more modern procedures with more modern technology,” Dr. Solomon said.
This similarity was not what Dr. Solomon expected. “It was a surprise to me. I think that modern technology helps because just placing blue ink marks on an eye is inaccurate,” he said, adding that ink marks can bleed, and the orientation is not very precise. Dr. Solomon theorized that one reason the manual technique fared as well as it did could be related to the use of modern IOL formulas, which include posterior corneal astigmatism.
Despite the findings, in Dr. Solomon’s view, modern technology may still be helpful. “I think that modern technology plays a role because I know that when I put my ink marks on, they smear and are sometimes hard to see in surgery,” he said. “They don’t necessarily take into account the rotation of the eye as accurately during surgery.”
However, it all comes down to individual results. “The bottom line is that surgeons should be looking at their outcomes and if their outcomes aren’t what they would like them to be, they should look into the newer technology,” Dr. Solomon said.
One limitation of the study could be that both groups fared so well, leaving little room for distinction. “It would be hard for the more modern technique to beat the manual one because the results of both groups were so good,” he said. From a clinical perspective, this means that if someone is already getting good results with a manual approach, perhaps the modern technology won’t help to the same degree, Dr. Solomon said, adding that if they’re getting more variable results, the modern technology may be of assistance.

Clinical takeaways

Dr. Solomon hopes that practitioners come away from the study with several key messages. “One take-home message for me was that modern IOL formulas that take into account posterior astigmatism have made a difference,” he said. “Even my manual technique is better.”
The second message highlights the fact that with a manual technique, practitioners have to be judicious with where they place their marks and with every aspect of their technique. “You have to make sure that everything is correct,” he said, adding that this means steps such as marking the patient’s eye while they are sitting up so that you can take into account cyclorotation.
A third message is that the automated systems work very well.
Finally, it’s incumbent on practitioners to track their own outcomes. “If they’re getting good outcomes, they may not feel the need to move to some of the newer technology,” he said. “But if they’re not getting the outcomes that are achievable with modern technology, this may be a benefit.”

About the doctor

Kerry Solomon, MD
Carolina Eye Care Physicians
Mount Pleasant, South Carolina

References

1. Solomon KD, et al. Correcting astigmatism at the time of cataract surgery: Toric IOLs and corneal relaxing incisions planned with an image-guidance system and intraoperative aberrometer versus manual planning and surgery. J Cataract Refract Surg. 2019;45:569–575.

Relevant disclosures

Solomon: Alcon, Johnson & Johnson, Carl Zeiss Meditec

Contact

Solomon: kerry.solomon@carolinaeyecare.com

Traditional vs. modern techniques in managing astigmatism Traditional vs. modern techniques in managing astigmatism
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