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PUBLICATION EXCLUSIVE: Increase accuracy of preop measurements with ‘markerless’ toric IOL alignment techniques
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Refractive cataract surgery continues to gain in popularity among both cataract surgeons and their patients because advanced technology and surgical techniques seem to deliver improved visual outcomes. Among cataract surgery patients, corneal astigmatism of greater than 1 D was noted in 40% of eyes in a U.K. study and 50% of eyes in an Italian study, greater than 1.25 D in 27.5% of eyes in a Chinese study, and greater than 2 D in 8% of eyes in a German study.
Optimal optical visual quality is bestowed by attaining uncorrected emmetropia or corrected emmetropia that includes sphere, cylinder, or both sphere and cylinder. With the insertion of an intraocular prosthetic device such as the standard IOL, the spherical correction can be greatly improved toward emmetropia, utilizing preoperative testing devices such as the IOLMaster (Carl Zeiss Meditec), Lenstar (Haag-Streit) and AL-Scan optical biometer (Nidek). This surgical approach serves well for patients with preoperative spherical correction, while those with astigmatism are treated with limbal relaxing incisions and/or postoperative spectacle or contact lens correction.
With continued improvements in IOL technology, we now have the toric IOL, which can potentially bestow the optimal visual acuity after cataract surgery without often requiring any external corrective devices such as glasses or contact lenses. However, a toric IOL needs to be placed on axis to deploy its complete IOL correction to the operated eye. Misalignment of a toric IOL can result in a suboptimal or detrimental surgical outcome. Surgeons have used various intraoperative manual and laser-assisted techniques to facilitate proper toric IOL placement.
In this column, Dr. Peets describes his technique of markerless toric IOL placement.
Thomas “TJ” John, MD
OSN Surgical Maneuvers Editor
Optical biometry with the IOLMaster 500 (Carl Zeiss Meditec) has increased the accuracy of my preoperative cataract surgery measurements with new imaging and reference tools (Callisto, Carl Zeiss Meditec), which have reduced postoperative toric IOL misalignment in my practice. This technique integrates data from the optical biometer into the surgical microscope (OPMI Lumera, Carl Zeiss Meditec) and works primarily by obtaining a reference image of the eye at surgery and matching it to a reference image of the eye obtained by the optical biometer, using limbal vessels as guides. Here is my step-by-step process for increasing the accuracy of my preoperative cataract surgery measurements.
- Click here to read the full publication exclusive, Surgical Maneuvers, published in Ocular Surgery News U.S. Edition, July 10, 2017.