Comparison Of Visual And Refractive Outcomes After Smile For Low To Moderate Myopic Astigmatism Using Visumax500 And Visumax800 Laser Platforms

To compare visual and refractive outcomes after small incision lenticule extraction (SMILE) for low to moderate myopic astigmatism using the VisuMAX500 and VisuMAX800 femtosecond laser platforms.

The study was conducted at Wollongong Eye Specialists ophthalmology clinic. Patients were treated with VisuMAX500 or VisuMAX800, based on clinical standard of care at the time of surgery.  This real-world study setting ensured that outcomes reflected everyday clinical practice and standard of care postoperative assessment up to 6 weeks.

A retrospective review was conducted on 60 eyes from 41 patients treated for myopic astigmatism (preoperative cylinder ≥0.75 D) with SMILE, utilising either the VisuMAX500 (30 eyes, 21 patients) or VisuMAX800 (30 eyes, 20 patients) laser systems. Postoperative evaluations at 6 weeks included uncorrected distance visual acuity (UDVA), manifest refraction, and best-corrected distance visual acuity (BCVA). Vector analysis assessed accuracy of astigmatic correction in low (0.75–1.0 D) and moderate (1.25–2.0 D) subgroups.

Mean postoperative spherical equivalent (SE) was similar between groups (P=0.174) with 97% of eyes achieving ±1.0 D of target SE. While mean postoperative UDVA was similar between groups (P=0.121), the VisuMAX500 group achieved statistically better postoperative BCVA than VisuMAX800 (LogMAR-0.07±0.05 vs -0.02±0.04 respectively; P<0.001).  However, this difference was not clinically significant and was within the pre-determined equivalence margin of logMAR±0.1 or ±5 letters. Astigmatic correction was more accurate in eyes treated with VisuMAX800, with a greater rate of undercorrection for low astigmatic corrections (CI=0.75 for VisuMAX500 vs CI=0.86 for VisuMAX800) compared to moderate (CI=0.84 for VisuMAX500 vs CI=1.09 for VisuMAX800).

The VisuMAX800 laser platform achieved excellent visual outcomes that was equivalent to VisuMAX500.  Furthermore, while both platforms achieved excellent astigmatic correction, VisuMAX800 showed a slight advantage. Although the VisuMAX800 incorporates the latest software and technological advancements (Centralign and Oculign), the VisuMAX500 remains a clinically effective alternative in regions where the 800 is not widely available in patients with low to moderate myopic astigmatism. This ensures that patients can still achieve reliable outcomes with the VisuMAX500 platform despite potential accessibility barriers.