Visual and Refractive Outcomes of Myopic Lenticule Extraction with the Zeiss VisuMax 500 and 800 Systems

This study aimed to compare the visual outcomes, safety and efficacy of myopic keratorefractive lenticule extraction treatments using the newer Zeiss VisuMax 800 system over its precursor, the VisuMax 500 system.

A retrospective review conducted at a private clinic in Western Australia of myopic keratorefractive lenticule extraction treatments with the VisuMax 500 and the VisuMax 800 systems between July 2021 and February 2023. Pre-operative and 1-month post-operative data were compared between the two cohorts. Demographics, best corrected visual acuity, uncorrected distance visual acuity, mean refractive spherical equivalent, total suction time and complications were recorded.

Fifty procedures for each system were identified. Eight eyes in the VisuMax 500 cohort (group 1) and five eyes in the VisuMax 800 cohort (group 2) were excluded due to non-attendance at the 1-month post-operative review. The average total suction time was 34 seconds vs 13 seconds respectively. A single case of suction loss occurred in group 1. The mean pre-operative mean refractive spherical equivalent of groups 1 and 2 were -6.02D (-3.63 to -9.00) and -5.56D (-2.75 to -8.88) (P = 0.20). The mean post-operative mean refractive spherical equivalent of the two groups were 0.08D (-1.00 to 1.25) and -0.03D (-2.25 to 1.00) (P = 0.31).

The VisuMax 500 and 800 systems have similar visual outcomes and no significant difference in safety profiles. The main advantage of the newer VisuMax 800 femtosecond laser is its speed and potential for less cases of suction loss. Larger studies over longer terms are required.