Comparison of toric implantable collamer lens alignment accuracy: VERION image-guided system versus manual marking

AIM: To compare the accuracy of manual marking versus an image-guided system for toric implantable collamer lens (TICL) implantation and evaluate the short-term postoperative rotational stability of TICL and corneal surgically induced astigmatism vector (SIA). METHODS: Retrospective analysis was conducted on eyes with TICL alignment achieved through manual marking (n=75) or VERION image-guided system-assisted marking (n=83). Each group was further classified into horizontal and vertical subgroups based on implant orientation. Additionally, patients were categorized into superior and temporal incision subgroups according to the position of main corneal incision. The misalignment and rotational stability of TICL were analyzed using slit-lamp anterior segment photography. Surgical predictability, efficacy, safety, and corneal SIA were also evaluated. RESULTS: In general, the TICL implantation with manual and digital image-guided systems all achieved robust predictability, efficacy, and safety. The misalignment of TICL was comparable between the manual and VERION groups (0.16°±3.97° vs 0.52°±5.59°, P=0.633), while a significant difference was observed in the absolute misalignment of TICL between the two groups (3.02°±2.55° vs 4.28°±3.61°, P=0.043). There were no significant differences in the distribution of TICL misalignment between the manual and VERION groups or between horizontal and vertical implant orientation groups (P>0.05). Furthermore, different orientations of TICL placement did not show statistically significant differences in rotational stability (P=0.46). Statistically significant differences were found in anterior corneal SIA between the manual and VERION groups (0.46±0.27 vs 0.33±0.21 D, P=0.001), especially for superior incision position (0.60±0.27 vs 0.35±0.23 D, P<0.0001). The anterior SIA exhibited a significant difference between superior and temporal incisions in the manual group (0.60±0.27 vs 0.35±0.20 D, P<0.0001). CONCLUSION: Compared with the conventional manual marking method, this study indicates that the digital image-guided system with VERION is safe and effective in TICL implantation. The digital system offers the advantage of minimizing corneal SIA compared to the manual method.