Related Experiment Video
Updated: Aug 29, 2026
Comparison of Agreement and Accuracy using Binocular Wavefront Optometer with Autorefractor and Phoropter
Published on: September 16, 2025
Comparative Assessment of Cap Geometry in Small Incision Lenticule Extraction (SMILE) Using VisuMax 500 (500 kHz) and
1Ophthalmology, Onnuri Smile Eye Clinic, Seoul, KOR.
Background:
In small incision lenticule extraction (SMILE), cap geometry can vary depending on the specific laser platform employed. Because differences in laser delivery speed between the VisuMax 500 (500 kHz) and VisuMax 800 (2,000 kHz) alter the duration of corneal applanation, variations in intraoperative stability and subsequent cap geometry may occur. To address this, this study compared corneal cap geometry between the VisuMax 500 and VisuMax 800 platforms and evaluated its associations with postoperative clinical outcomes.
Methods:
This retrospective comparative study included eyes that underwent SMILE using either the VisuMax 500 or 800 system. One month postoperatively, corneal cap thickness was measured at nine horizontal points using anterior-segment optical coherence tomography. Cap accuracy was defined as the difference between achieved and intended thickness. Cap uniformity was quantified using the intra-subject standard deviation (SD) across the central 2.0-mm zone (central uniformity) and the full 6.0-mm zone (total uniformity). Correlations between uniformity and clinical outcomes were analyzed.
Results:
No significant differences were observed in achieved cap thickness, cap accuracy, visual acuity, refraction, or higher-order aberrations between groups. However, the VisuMax 800 group demonstrated significantly superior central uniformity, with a significantly lower intra-subject SD (2.5 ± 1.2 µm) compared with the VisuMax 500 group (3.5 ± 1.6 µm; p = 0.010). In exploratory correlation analyses within the VisuMax 800 group, total uniformity correlated with postoperative sphere, spherical equivalent, and changes in spherical aberration, while central uniformity associated with changes in other higher-order aberrations; no such associations reached significance in the VisuMax 500 group.
Conclusions:
The VisuMax 800 provides significantly improved central cap uniformity compared with the VisuMax 500 while maintaining similar cap accuracy and visual outcomes. These exploratory findings indicate that the VisuMax 800 platform is associated with greater central geometric consistency during cap creation, though observed correlations should be considered hypothesis-generating and require future prospective confirmation.
