Vector Analysis Comparing Cylinder Adjustment In Ray-Tracing Guided Vs Q-Value Adjusted Fs-Lasik For Correcting Mid-High Astigmatism (≥ 1.50D). Abstract
Published 2026 - 44th Congress of the ESCRS
Reference: FP31.05 | Type: Free paper | DOI: 10.82333/tkme-jb67
Authors: Dr Jihong Zhou* 1 , Dr Fengju Zhang 2 , Dr Wenjun Wang 1 , Dr Guoli He 1 , Dr Dan Wei 1 , Dr Nuan Peng 1 , Mrs Yan Gao 1 , Mrs Jing Yao 1 , Mrs Hongwei Wang 1
1Refractive surgery ,Beijing AierIntech Eye Hospital,Beijing,China, 2Refractive surgery ,Beijing AierIntech Eye Hospital,Beijing,China;Refractive surgery ,Beijing Tong ren Hospital, Capital Medical University,Beijing,China
Purpose
Vector analysis was used to compare the outcomes of femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for correcting moderate-to-high astigmatism (≥1.50D) between the ray-tracing-guided (RT) and Q-value-adjusted (QV) approaches.
Setting
Beijing AierIntecth Eye Hospital. The study was designed as a retrospective cohort study.
Methods
Patients with myopia and myopic astigmatism of ≥1.5D who underwent ray-tracing- or Q-value-guided FS-LASIK were included in the study. The cylinder correction was carefully adjusted in the two groups. Alpins' vector analysis was employed to evaluate astigmatism correction, and a linear mixed model (LMM) was used to compare the results, accounting for both binocular correlation and its variation. The study included 104 eyes in the RT group (48 right, 56 left) and 148 eyes in the QV group (70 right, 78 left). The baseline of the two groups was as follows: age (RT group: 22.70 ± 6.61 ys; QV group: 26.95 ± 6.77ys), spherical equivalent (RT group: -5.17 ± 1.85D; QV group: -5.18 ± 1.96D), astigmatism (RT: -2.17 ± 0.59D; QV: -2.17 ± 0.63D).
Results
Aside from age (P<0.001), UDVA (P=0.011), and CDVA (P=0.028), no significant baseline differences existed between groups. 3 months postoperatively, there were no statistically significant differences in SEQ, UDVA, and CDVA between the RT and QV groups after adjustment for covariates (P=0.301, 0.709, 0.173). Astigmatism in RT group: ≤0.25D 55%, ≤0.50D 87%, ≤1.00D 100%; in QV group: ≤0.25D 46%, ≤0.50D 78%, ≤1.00D 99%, with P values 0.166, 0.076, 0.513. Angle of error (AE): -5º to +5º: RT 48.1%, QV 47.3% (P=0.903); <-15º and >+15º: RT 3.85%, 3.85%; QV 5.41%, 4.05%; P=0.567, 0.934 respectively; Vector analysis found no significant interaction between eye and group (P≥0.05).
Conclusions
TIA, SIA, CI, AE, AbsAE, ME, FE, FI, and IOS showed no significant differences (P=0.765, 0.625, 0.293, 0.925, 0.228, 0.168, 0.492, 0.163, 0.260), whereas DV showed a significant difference (P=0.038), favoring the RT group. Both ray-tracing-guided and Q-value-adjusted FS-LASIK are safe and effective in correcting myopia and moderate-to-high astigmatism (≥1.5D), with the ray-tracing-guided method exhibiting superior accuracy.