Comparison of lenticular scanning quality and visual outcomes of keratorefractive lenticule extraction between VisuMax 800 and 500 systems

PURPOSE: To compare lenticular scanning quality and visual outcomes between keratorefractive lenticule extraction performed with VisuMax 800 and VisuMax 500 systems. SETTING: Single ophthalmic surgical center. DESIGN: Comparative, nonrandomized prospective study. METHODS: Consecutive patients aged 18 to 46 years were recruited between November 2024 and March 2025. Opaque bubble layer (OBL) and lenticular surface regularity were measured using intraoperative imaging and scanning electron microscopy. Visual acuity and refractive error were assessed at 1 month, 3 months, and 6 months postoperatively. RESULTS: A total of 140 participants (140 eyes) were included (70 per group). The VisuMax 800 group had significantly lower OBL proportions (3.97% ± 2.58% vs 2.44% ± 0.52%, P = .013) and better lenticular surface regularity scores (11.85 ± 2.56 vs 14.98 ± 4.05, P = .048). In the VisuMax 800 group, higher flat K and steep K correlated with larger OBL areas (β = 0.412, P < .001; β = 0.358, P = .002) and larger optical zones were associated with better lenticular surface regularity (β = 0.535, P = .038). No statistically significant difference was observed in the visual and refractive outcomes between the 2 groups at the 6-month postoperative follow-up ( P > .05). In the VisuMax 800 group, smaller OBL proportions were associated with better visual acuity at 1 and 3 months postoperatively (β < 0, P < .05), while better lenticular surface regularity was correlated with lower astigmatism at 3 months postoperatively (β = -0.574, P = .002). CONCLUSIONS: Although technical advancements of the VisuMax 800 may optimize intraoperative lenticular scanning quality, the VisuMax 800 and 500 systems yield comparable visual outcomes.