Pilot Study on Postoperative Toric Intraocular Lens Alignment: Comparing Casia2 and Photoshop Imaging Techniques

Assess the comparative accuracy and reliability of postoperative toric intraocular lens (TIOL) alignment measurement methods: Casia2 and Adobe Photoshop with digital slit lamp images (PS method). In a study of 41 subjects with 58 eyes postimplantation of TIOL, we independently measured TIOL alignment with Casia2 and PS methods. The intraclass correlation coefficient (ICC ) was employed to assess the repeatability of the Casia2 method. While ICC for absolute agreement and Bland-Altman analysis were utilized to determine the interdevice agreement between the two methods, the regression analysis was conducted to identify any proportional bias. Casia2 demonstrated excellent intradevice repeatability with an ICC of 0.998. The absolute agreement between Casia2 and PS was very high with an ICC of 0.999. The average discrepancy between the two measurement methods was -0.828°, with a 95% confidence interval (CI) ranging from -1.623° to -0.032°. The 95% limits of agreement (LoA) were between -6.761° and 5.105°, indicating a strong concordance in TIOL alignment measurements. Casia2 was capable of accurately measuring the TIOL axis alignment under conditions of pupil diameters (PDs) of 4 mm or greater. Casia2 and PS demonstrated significant concordance in measuring postoperative TIOL alignment, with Casia2 offering a more straightforward and accessible alternative, particularly beneficial for patients with suboptimal pupil dilation.