Avoiding common errors crucial for success with toric IOLs
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Key takeaways:
- Correcting astigmatism in cataract surgery is crucial, and toric IOLs are the most effective method.
- An expert explains how to prevent sources of error and refine the implantation technique.
VILAMOURA, Portugal — Toric IOLs are the most effective and predictable method of astigmatic correction.
Adoption of this technology has doubled in 5 years between 2016 and 2021 and would be even wider if cost were not an issue, according to Filomena Ribeiro, MD, PhD.
In a symposium at the European Society of Cataract and Refractive Surgeons winter meeting, Ribeiro shared pearls on how to successfully use these lenses, being aware of the most common sources of error.
“With high astigmatism, the problem is alignment, while with lower degrees, it is measurement error. For all degrees, we must consider that posterior astigmatism is very relevant,” she said.
A common cause of error is tilt. A tilt of 6°, which is not uncommon, may not have huge consequences for the average case, but with high-power IOLs, it leads to an error of 0.5 D.
“The only calculator for toric IOLs that considers this issue is the Panacea calculator,” Ribeiro said.
Rotational stability is also crucial for achieving accurate cylinder correction, and progressive changes in material and haptic design have been introduced over the years to improve this important aspect.
To achieve the best outcomes, surgeons should consider a number of steps: preoperative evaluation, IOL calculation, axis marking, intraoperative alignment, postoperative evaluation of IOL rotation, and surgically induced astigmatism optimization.
“Preoperatively, we need to assess the ocular surface. If we treat dry eye, we can have cases below 0.5 D of astigmatism,” Ribeiro said.
She emphasized the importance of considering the posterior corneal curvature at the stage of IOL calculation.
“Most of the devices we currently use have nomograms that consider the posterior surface, and this makes it easier for all of us,” she said.
Axis marking and IOL alignment can be performed manually, but digital image-guided marking leads to more reliable outcomes.
To minimize rotation, Ribeiro recommended removing all viscoelastic from behind the IOL and slightly pushing the optic posteriorly to ensure a good adhesion to the posterior surface of the capsule.
“We need a good overlay of the capsulorrhexis. And the main issue for me is to not overinflate the bag at the end of the surgery but check if there is leakage in the wound,” she said.
A centroid value should be used for surgically induced astigmatism.
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Ribeiro F. Top 10 pearls for success with toric IOLs. Presented at: European Society of Cataract and Refractive Surgeons winter meeting; March 10-12, 2023; Vilamoura, Portugal.
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