Ocular surface parameters repeatability and agreement -A comparison between Keratograph 5M and IDRA

Area of Science:

• Ophthalmology
• Optometry
• Biomedical Engineering

Background:

• Dry eye disease (DED) diagnosis relies on objective measurements of ocular surface parameters.
• Ocular surface analyzers like Oculus Keratograph 5M (K5M) and SBM Sistemi IDRA (IDRA) are used to assess DED.
• Understanding the agreement and repeatability of measurements between different devices is crucial for clinical practice and research.

Purpose of the Study:

• To evaluate the repeatability and agreement of dry eye measurements obtained using the Oculus Keratograph 5M (K5M) and SBM Sistemi IDRA (IDRA).
• To compare measurements of tear meniscus height (TMH) and non-invasive tear break-up time (NIBUT) between the two devices.

Main Methods:

• 108 participants and 108 eyes were evaluated.
• Tear meniscus height (TMH) and first and average non-invasive tear break-up time (NIBUT) were measured using K5M and IDRA in a randomized order.
• TMH was measured using the caliper tool, while NIBUT was calculated using the instruments' automatic algorithms.

Main Results:

• Good agreement was observed between K5M and IDRA for TMH measurements (95% LoA: -0.17 to 0.16).
• Non-invasive tear break-up time (NIBUT) measurements showed poor agreement between the devices (first NIBUT 95% LoA: -8.13 to 14.79; average NIBUT 95% LoA: -7.89 to 10.32).
• IDRA consistently yielded significantly shorter NIBUT values compared to K5M. Some parameters (TMH and average NIBUT by K5M; TMH by IDRA) showed measurement instability across three repetitions.

Conclusions:

• Non-invasive tear break-up time (NIBUT) measurements are not interchangeable between the IDRA and K5M devices.
• Tear meniscus height (TMH) measurements showed minimal differences between the two instruments.
• Clinicians should exercise caution when comparing ocular surface measurements obtained from different devices to avoid errors.