Comparison Of Early Visual Quality After Keratorefractive Lenticule Extraction (Klex) Using Visumax 500 And Visumax 800

Single-center retrospective comparative study conducted at Beijing Aier Intech Eye Hospital refractive surgery center.

This retrospective study analyzed 332 eyes(167 patients) treated with VisuMax 500 and 414 eyes (219 patients) treated with VisuMax 800 at Beijing Aier Intech Eye Hospital from May 2025 to September 2025. All surgeries were performed by the same surgeon.Preoperative baseline data and 3-month postoperative parameters were collected, including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent (SE), residual astigmatism, higher-order aberrations(HOAs ),and subjective visual quality questionnaire. Statistical comparisons were performed using independent t-tests and paired analyses where appropriate.

For the baseline,there was no difference between the two groups except for preoperative larger astigmatism and HOAs in VisuMax 800 group.3 months after surgery,there was no statistically difference between VisuMax 500 and VisuMax 800 in efficacy (p=0.86) and safety  (p=0.79); VisuMax 800 demonstrates superior predictability within±0.50 D(86.5% vs 81.3%) ;the difference in UDVA(p=0.504), SE(p=0.12) and residual astigmatism (p=0.25) was not significant; there was no difference between the two groups in HOAs.  Subjective questionnaires indicated comparable proportions in severe glare, halos, and starburst of two groups,but VisuMax 800 showed slight foggy and blurry symptoms.No sight-threatening complications were observed in either group.

The VisuMax 500 and VisuMax 800 systems have similar efficacy and safety ;VisuMax 800 may offer advantages in predictability, large astigmatism correction,reducing postoperative HOAs and less visual interference;Further studies over longer follow-up period are required to verify the advantage.of VisuMax 800.