Keratorefractive Lenticule Extraction Using a Novel Nomogram Software Tool for High Astigmatism: Refractive Outcomes and Aberrations

Purpose: To develop a VISULYZE (Carl Zeiss Meditec AG)–generated nomogram for keratorefractive lenticule extraction (KLEx) in patients with high astigmatism and to compare refractive accuracy and visual outcomes between surgeries performed with and without the nomogram. Methods: This study included 43 patients (57 eyes) with pre-operative refractive astigmatism of 1.50 diopters (D) or greater who underwent KLEx with the VISULYZE nomogram and 34 patients (45 eyes) in a matched control group who underwent KLEx without the nomogram. The primary outcomes were the predictability of residual astigmatism and higher order aberrations at the 3-month follow-up visit. Results: In the VISULYZE group, 98% of eyes achieved uncorrected distance visual acuity (UDVA) better than 20/20 versus 95% in the control group. UDVA equal to or better than preoperative corrected distance visual acuity (CDVA) was achieved in 98% versus 95% and residual astigmatism of 0.50 D or less occurred in 100% versus 88.9% of eyes. Correlation ( R 2 ) between attempted and achieved astigmatism was 99.49% and 98.46%, respectively. Astigmatic axis deviation within ±5 degrees occurred in 87.3% versus 60.0%. The VISULYZE group showed significantly lower total eye coma ( P < .05), trefoil aberration ( P < .01), anterior corneal vertical trefoil ( P < .05), and posterior corneal spherical aberration ( P < .05) at 3 months. Conclusions: KLEx with the VISULYZE nomogram is safe, effective, and provides superior refractive accuracy and visual quality in eyes with astigmatism of 1.50 D or greater. Further follow-up is needed to assess long-term safety and stability.