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The VX120 multidiagnostic unit shows good repeatability for corneal power, white-to-white distance, anterior chamber depth, and central corneal thickness. However, measurements for sphere, cylinder, and aberrations were less repeatable in healthy eyes.

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Area of Science:

  • Ophthalmology
  • Optometry
  • Biomedical Engineering

Background:

  • The VX120 is a multidiagnostic instrument integrating autorefraction, keratometry, corneal topography, aberrometry, pachymetry, and tonometry.
  • Assessing the reliability of diagnostic instruments is crucial for clinical decision-making and research.

Purpose of the Study:

  • To evaluate the intrasession repeatability and intersession reproducibility of all parameters measured by the VX120 multidiagnostic unit.
  • To assess the performance of the VX120 in a cohort of normal, healthy eyes.

Main Methods:

  • Three repeated measurements were performed on the right eye of volunteers using the VX120.
  • Repeatability and reproducibility were analyzed for various parameters including corneal power, aberrations, and central corneal thickness.
  • Statistical metrics such as within-subject standard deviation (Sw), coefficient of variation (CV), and intraclass correlation coefficient (ICC) were calculated.

Main Results:

  • Low coefficients of variation (CV) were observed for anterior corneal power (K flat and K steep), white-to-white (WTW) distance, anterior chamber depth (ACD), and central corneal thickness (CCT), ranging from 0.34% to 1.16%.
  • Higher CVs were found for sphere, cylinder, high- and low-order aberrations (HOA-RMS and LOA-RMS), and eccentricity, ranging from 6.92% to 54.24%.
  • Intraclass correlation coefficients (ICC) were generally high, except for HOA-RMS and eccentricity, indicating good to moderate agreement.

Conclusions:

  • The VX120 demonstrates repeatable measurements for anterior corneal power, WTW, ACD, and CCT in healthy eyes.
  • Repeatability was less favorable for refractive error parameters (sphere, cylinder) and aberrometric data (HOA-RMS, LOA-RMS, eccentricity).
  • Intersession reproducibility was generally good, with minimal differences observed between measurement sessions.