Accuracy of Toric Intraocular Lens Implantation Using Three-Random-Point Marking Method: A Prospective Pilot Study

This study aimed to compare the accuracy of three-random-point (TRP) marking method with the slit-lamp horizontal meridian (SHM) marking method by using an image-guided system in the positioning of a toric intraocular lens (IOL).

A total of 60 eyes of 54 patients who underwent cataract surgery were prospectively randomized into 3 groups (each group included 20 eyes: Group 1, novice doctor and dilated pupil patient; Group 2, novice doctor and small pupil patient; and Group 3, experienced doctor and small pupil patient). Every patient was marked three points (horizontal two points and random third point) in corneal limbus with a staining blunt needle and then measured by the iTrace system. The axis deviations from the SHM method (axis A, horizontal two points method) and the TRP method (axis B, three points method) were measured by the digital image-guided navigation system.

The axis deviations of each group showed a significant difference between the SHM and TRP marking methods (Group 1: SHM method: 3.05° ± 2.58° and TRP method: 0.85° ± 0.93°, p < 0.01; Group 2: SHM method: 2.15° ± 2.35° and TRP method: 1.05° ± 1.57°, p < 0.05; and Group 3: SHM method: 1.00° ± 1.84° and TRP method: 0.45° ± 1.23°, p < 0.05).

The TRP marking method using the iTrace aberrometer was found to be more effective and more accurate than SHM marking method in the positioning of toric IOLs before surgery. Trial Registration: Chinese Clinical Trial Registry: ChiCTR2600121114.