Impact Of Postoperative Corneal Morphology Changes In Different Optical Zones On Visual Quality After Ray-Tracing-Guided Fs-Lasik
Published 2025 - 43rd Congress of the ESCRS
Reference: FP02.11 | Type: Free paper | DOI: 10.82333/t7q9-tk75
Authors: Ashmal Jameel* 1 , Chun Kit David Chan 2 , Scott Robbie 3 , Vijay Wagh 3 , Sancy Low 3 , Maninder Bhogal 3 , Elodie Azan 3 , Seema Verma 3 , David O'Brart 1
1Ophthalmology,St Thomas' Hospital,London,United Kingdom;King's College London,London,United Kingdom, 2Ashford & St Peter's Hospital,Surrey,United Kingdom, 3Ophthalmology,St Thomas' Hospital,London,United Kingdom
Purpose
To assess the postoperative corneal morphology across various optical zones and to investigate the impact on postoperative visual quality in patients who underwent ray-tracing-guided femtosecond laser-assisted in situ keratomileusis (FS-LASIK).
Setting
This study comprised 60 eyes from 60 patients (33 males and 27 females). Among them, 30 patients aged 23.63 ± 6.26 underwent ray-tracing-guided FS-LASIK, while the other 30 patients, aged 24.93 ± 6.65 years, underwent Custom-Q FS-LASIK. The preoperative spherical equivalent (SE) was -4.15 ± 1.70 D and -5.08 ± 1.62 D, respectively. Postoperatively, all enrolled patients achieved a UDVA of ≥ 20/20. Notably, 89.47% of patients in the ray-tracing-guided FS-LASIK group achieved a UDVA of 20/16.
Methods
Preoperative and 3-month postoperative evaluations were conducted, encompassing the measurement of uncorrected distant visual acuity (UDVA), corrected distance visual acuity (CDVA), intraocular pressure (IOP), spherical equivalent (SE), wavefront aberrations within 4 mm, 5 mm, and 6.5 mm optical zones (OZ4, OZ5 and OZ6.5), corneal volume (CV) in OZ3, OZ5 and OZ7, and Q-value in OZ5 and OZ6.5. The corneal ablation ratio (CAR) was defined as the ratio of the difference between preoperative and postoperative CV to the absolute value of preoperative SE. PSF, MTF, contrast sensitivity (CS), and the Quality of Vision (QoV) questionnaire score were employed to evaluate both objective and subjective visual quality.
Results
Ray-tracing-guided FS-LASIK demonstrated superior results compared to Custom-Q FS-LASIK in terms of postoperative CDVA, PSF, MTF and CS. Q-value remained more negative in OZ5 (-0.09 ± 0.35) and OZ6.5 (0.34 ± 0.35), and was significantly lower than that of Custom-Q group after surgery (P < 0.05). Postoperative SA obviously decreased in ray-tracing-guided group in OZ4, OZ5 and OZ6.5 compared with Custom-Q group (P < 0.05). The CAR in OZ3 and OZ5 showed no significant difference between the two group, however, the CAR in OZ7 significantly increased in patients of ray-tracing-guided FS-LASIK (P < 0.05).
Conclusions
Ray-tracing-guided FS-LASIK demonstrates enhanced ablation patterns by removing a greater volume of peripheral corneal stroma within 5-mm to 7-mm optical zones, which effectively preserves corneal asphericity, while significantly reducing spherical aberration across all optical zones. Consequently, patients achieved optimal visual quality under both photopic and scotopic conditions following the procedure.