Intraoperative Degree Misalignment in Toric Intraocular Lens Implantation When Using Conventional Compared to Digital Marking

Purpose: To evaluate the difference in degrees between a digital marker and a manual marker as measured intraoperatively. Methods: This was a prospective, single-site, comparative, observational study. Preoperative biometry and planning was assessed with the Argos SS-OCT biometer. All subjects received both digital and conventional marking. The ToriCAM application was used to mark the patient manually at the bedside. A Mendez marker was used to mark the final axis of the IOL, as calculated by Argos. Digital marking was performed using the VERION image guided system. The primary outcome measure was the difference in degrees between the digital marker and the manual marker as measured intraoperatively. Other outcome measures included IOL rotation, residual astigmatism, absolute prediction error (APE), and monocular visual acuity at 2 months postoperatively. Results: A total of 41 eyes of 41 subjects completed the study. At 2 months postoperatively, the absolute difference in degrees between intraoperative digital and manual marking was 6.6 ± 5.2 (range 0.0 to 22.5). Mean absolute IOL rotation in degrees was 3.5 ± 2.9 (range 0.3 to 14.8) at 2 months. Mean postoperative residual astigmatism was 0.24 ± 0.24 D, and mean APE (spherical equivalent) was 0.39 ± 0.27 D. Mean monocular corrected distance visual acuity was 0.02 ± 0.05 logMAR. Conclusion: Results suggest good postoperative refractive accuracy was achieved using Argos combined with a digital marker microscope. The manual marking was significantly misaligned when compared to the intended digital marking axis, which may cause significant postoperative residual astigmatism.