Intraoperative Measurement of Crystalline Lens Diameter in Living Humans

There are no reports on accurate measurement of lens equatorial diameter of the living human eye. This study aimed to measure lens equatorial diameter with a special measurement device during cataract surgery and examine the relationships with preoperative parameters.

From April 7 to December 1, 2019, the equatorial diameters of 24 eyes from 24 patients who underwent cataract surgery at Kushimoto Arita Hospital were measured with a loop shaped measurement device during cataract surgery. Correlations between the value of the diameters and various preoperative parameters measured by CASIA2^® were evaluated.

The average value of the measured equatorial diameter using the device was 10.5 ± 0.4 mm and the value estimated by circular approximation using the CASIA2^®️ was 10.1 ± 0.7 mm. A significant difference was observed between these two groups (P = 0.016), and only a weak correlation was observed (γ = 0.31). A positive correlation was observed between equatorial diameter and anterior chamber depth (ACD) or anterior chamber width (ACW) (γ = 0.57 and 0.47, respectively). No significant correlation was found between other parameters and the value measured by the device.

Our method is a completely new approach to measuring the living human lens equatorial region of the eye. No complications were observed in any of the cases. One new finding was the values of the lens equatorial diameters are actually longer than those reported previously. The results suggest that the values of the equatorial diameter measured by the loop device and those estimated by CASIA2^® measurement were closer than those reported previously by other methods, although both were slightly different. We conclude that it is still difficult to estimate the equatorial diameter of the living human lens using preoperative examination parameters. This research will greatly contribute to the development of accommodative intraocular lenses in the future.