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.
1 Wang L et al. J Cataract Refract Surg. 2019;45:35-40.
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.
For full disclosures and the disclosure key, see below.
Full Financial Disclosures
Dr. Bharti None.
Dr. Koch Alcon: C; Carl Zeiss Meditec: C; Johnson & Johnson: C.
Dr. Nouri-Mahdavi Heidelberg Engineering: L,S.
Dr. Pointdujour-Lim None.
||Consultant fee, paid advisory boards, or fees for attending a meeting.
||Employed by a commercial company.
||Lecture fees or honoraria, travel fees or reimbursements when speaking at the invitation of a commercial company.
||Equity ownership/stock options in publicly or privately traded firms, excluding mutual funds.
||Patents and/or royalties for intellectual property.
||Grant support or other financial support to the investigator from all sources, including research support from government agencies (e.g., NIH), foundations, device manufacturers, and/or pharmaceutical companies.
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