Evaluating Lens and IOL Tilt With SS-OCT Biometry

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Researchers have conducted a retrospective case series study of crys­talline lens and IOL tilt using a swept-source optical coherence tomography (SS-OCT) biometer.¹

“We found that we can reproducibly measure crystalline lens tilt—and that this tilt is predictive of postoperative IOL tilt,” said Douglas D. Koch, MD, at the Cullen Eye Institute in Houston. “Knowing this could improve the accu­racy of toric IOL calculations.”

TILT. Preoperative crystalline lens tilt and postoperative IOL tilt, measured in the same eye.

Study design. Dr. Koch and his colleagues evaluated 333 patients for:

• repeatability of the lens tilt measurement,
• preoperative crystalline lens and postoperative IOL tilt in the pa­tients’ right eyes (253 phakic, 80 pseudophakic),
• lens tilt mirror symmetry between the patients’ right and left eyes,
• correlation in tilt between preoper­ative crystalline lens and postoperative IOL, and
• correlation between the magnitude of lens tilt and ocular parameters.

Repeatability of crystalline lens tilt was calculated using participants with preoperative tilt data available for three repeated measurements on the same day. This was assessed using two parameters: 1) the pooled within-sub­ject standard deviations of repeated measurements, and 2) intraclass cor­relation coefficient, a measure of the correlation between repeated measurements. Repeatability using the SS-OCT was found to be excellent.

Because of the potential mirror sym­metry of lens tilt between right and left eyes, the researchers used the patients’ right eyes to assess the mean crystal­line lens and IOL tilt magnitudes and directions. In 163 phakic patients and 24 pseudophakic patients, there was significant mirror symmetry.

In the 65 eyes with both pre- and postoperative tilt measurements, there was significant correlation between tilt magnitude and tilt direction of preoperative crystalline lens and post­operative IOL. The IOL tilt magnitude increased significantly compared with the preoperative crystalline lens tilt.

In the 253 phakic right eyes, multi­ple regression analysis revealed that the magnitude of crystalline lens tilt was negatively correlated with axial length (AL), anterior chamber depth, and lens thickness, and positively correlated with angle α. In the 80 pseudophakic right eyes, the magnitude of IOL tilt was negatively correlated with AL and positively correlated with angle α and angle κ.

The researchers stressed that further studies evaluating incorporation of lens tilt in IOL power calculations in clinical patients are needed.

—Arthur Stone

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1 Wang L et al. J Cataract Refract Surg. 2019;45:35-40.

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Relevant financial disclosures—Dr. Koch: Carl Zeiss Meditec: C. This study was funded in part by the Sid W. Richardson Foundation and an unrestricted grant from Research to Prevent Blindness.

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