Digital versus manual axis marking for toric phakic intraocular lens alignment: a prospective randomized intraindividual trial.

Purpose: This study compares visual and refractive outcomes and postoperative axis alignment for toric Implantable Collamer Lens (ICL) implantation in astigmatic myopia using manual versus digital marking techniques.

Setting: Department of Ophthalmology, Medical University of Graz, Austria.

Design: Prospective randomized single-centered intraindividual comparison.

Methods: Patients undergoing bilateral toric ICL implantation for myopia with astigmatism ≥ 0.5 diopters (D) were enrolled. Patients received both marking techniques and randomization was performed. Postoperative retroillumination photography assessed axis alignment, and visual and refractive parameters were evaluated. Duration of the surgeries was recorded.

Results: The study includes 20 patients and 40 eyes. Preoperative visual and refractive parameters showed no significant differences. Postoperatively, residual astigmatism (p=0.824) and spherical equivalent (p=0.309) were comparable. No notable differences between right and left eyes in terms of preoperative (p=0.371) and postoperative (p=0.824) astigmatism were observed. Although slight, corrected distance visual acuity (CDVA) increased in both groups postoperatively (p=0.381). Gain in CDVA was comparable between marking techniques (p=0.637). Safety and efficacy indices were comparable (p=0.991 and p=0.189, respectively). Postoperative axial misalignment was 2.8±3.1 degrees in the digital- and 4.4±5.1 degrees in the manual group (p=0.260). Vector analysis showed no significant differences between manual and digital marking. Duration remained uninfluenced by the marking technique (p=0.970) and side of surgery (p=0.682).

Conclusion: In conclusion digital and manual marking techniques provided comparable results in axis alignment, surgical duration and visual and refractive outcomes. Both methods are viable for precise axis alignment, with digital marking offering a potential advantage in efficacy.