Non-Contact Laser Marking For Cyclotorsion Control In Myopia And Astigmatism Correction Using The Smile Pro Technique

To evaluate the additional effect of cyclotorsion error correction using non-contact laser corneal marking compared to standard manual ink-method using the horizontal slit beam of a slit lamp in the SMILE Pro technique.

Doctor Shilova’s Clinic

Consecutive patients (84) with mean preoperative myopic astigmatism of 2.0 diopters who elected to undergo refractive correction with the SMILE Pro procedure were included in this study. They were randomized into two treatment groups: manual marking (Group M: 40 eyes) and laser marking (Group L: 44 eyes) for cyclotorsion compensation. Laser marks were applied bilaterally at 4 mm and 8 mm from the limbus using remote focal YAG laser energy at 0.3–0.5 mJ per pulse with a power density of 8–12 mW/cm². Visual acuity and refractive outcomes were assessed preoperatively and postoperatively. Astigmatic refractive changes were analyzed using the Alpins method.

Groups M and L were comparable preoperatively in terms of age, manifest spherical equivalent, and manifest refractive cylinder. The mean positionally induced cyclotorsion  was 1.5 ± 2.3 degrees (range: 0 to 10 degrees) in Group M and 2.39 ± 3.45 degrees (range: 0 to 10 degrees) in Group L. The mean preoperative cylinder was -2.67 ± 0.54 D in Group M and -2.72 ± 0.71 D in Group L. Six months postoperatively, visual outcomes in Group L were significantly better than in Group M, with a mean postoperative corrected distance visual acuity of 0.97 ± 0.07 compared to 0.89 ± 0.10. Vector analysis of astigmatism also demonstrated superior results in Group L. However, both groups were statistically similar in spherical equivalent outcomes.

The SMILE Pro procedure combined with non-contact laser marking for cyclotorsion compensation significantly improved surgical outcomes in terms of safety, efficacy, and predictability for patients with astigmatism.