PURPOSE: To investigate the impact of static cyclotorsion correction using an automatic iris registration system on photorefractive keratectomy outcomes in patients with moderate and high astigmatism. METHODS: This study employed a prospective observational approach involving59 patients with moderate to high astigmatism who underwent PRK. Patients were categorized based on static cyclotorsion correction (SCC) into two groups: SCC <
2 degrees and SCC ≥ 2 degrees. Refractive errors and corneal aberrations were assessed before and6 months after surgery. Subjective refraction and visual acuity measurements were taken pre- and post-operation, and corneal aberrometry was conducted using Sirius device. All patients underwent PRK with the SCHWIND AMARIS 1050RS device. RESULTS: The study revealed a mean SCC value of 2.20 ± 1.46 among patients, with 33 exhibiting clockwise and 26 anti-clockwise eye rotations. Significant differences in mean J45 were observed post-surgery between SCC groups (<
2 vs. ≥ 2 degrees) (p = 0.033). Changes in refractive errors did not significantly differ between groups. Significant differences were noted in spherical aberration-related RMS pre- and post-surgery for both SCC categories. Correlations were found between SCC values and various aberration parameters at different corneal levels. CONCLUSION: Attention to SCC in PRK for moderate and high astigmatism patients is crucial, as SCC can significantly impact surgical outcomes, particularly concerning astigmatic vectors like J45 and corneal aberrations. Precise cyclotorsion adjustment is recommended to enhance vision quality, minimize post-operative aberrations, and optimize surgical outcomes in these populations.