Comparing toric intraocular lens alignment: intraoperative image-guided system versus manual marking in cataract surgery: a randomized clinical trial.

PURPOSE: To compare the accuracy of toric intraocular lens (IOL) alignment using the image-guided Callisto Eye system (M/S Carl Zeiss Meditech AG, Germany) versus the conventional manual marking method (Bubble marker) in cataract surgery.

DESIGN

Prospective, single-centre, double-masked, randomized controlled trial with two comparative arms. The study was registered with the Clinical Trial Registry of India (CTRI/2023/07/055833).

METHODS

A total of 76 patients aged 18 years or older, with cataract and corneal astigatism greater than 1.25 diopters (D), were enrolled. Patients were randomly assigned to either the image-guided group (Group 1 n = 38) or the manual marking group (Group 2 n = 38). Group 1 underwent IOL alignment using the Callisto Eye system, while Group 2 used the bubble marker manual technique. The primary outcome measure was IOL misalignment on postoperative day (POD) 1. Secondary outcomes included rotational stability, residual astigmatism, and uncorrected distance visual acuity (UDVA) on POD 30.

RESULTS

The mean IOL misalignment on POD 1 was 2.7 ± 3.6 degrees in Group 1 and 4 ± 3.1 degrees in Group 2, with no statistically significant difference (P = 0.108). Rotational stability showed a mean change of 0.71 ± 1.3 degrees in Group 1 and 0.78 ± 1.5 degrees in Group 2 (P = 0.815). Residual astigmatism was comparable between the groups (P = 0.176), and UDVA was similar, with no significant differences (P = 0.595).

CONCLUSION

Both the image-guided Callisto Eye system and the manual marking method demonstrated statistically equivalent effectiveness in toric IOL alignment, rotational stability, residual astigmatism, and UDVA.