Agreement and repeatability of infrared pupillometry and the comparison method

Area of Science:

• Ophthalmology
• Optometry
• Medical Device Evaluation

Background:

• Accurate pupil size measurement is crucial for various ophthalmic applications, including refractive surgery and clinical trials.
• The Rosenbaum card comparison method is widely used but its accuracy and repeatability require thorough evaluation.

Purpose of the Study:

• To assess the accuracy and repeatability of the Rosenbaum card comparison pupillometry method against infrared pupillometry.
• To determine the agreement and inter-rater reliability of pupil diameter measurements using both techniques.

Main Methods:

• A cross-sectional study involving 14 eyes of 7 healthy myopic subjects.
• Two examiners performed repeated pupil diameter measurements using Rosenbaum and infrared pupillometry under three luminance conditions.
• Analysis included pupil diameters, limits of agreement, and coefficient of repeatability.

Main Results:

• The Rosenbaum method consistently overestimated pupil diameters compared to infrared pupillometry across all conditions.
• While mean differences were small, the limits of agreement were large (2.4–2.8 mm).
• Inter-rater repeatability showed bias for the Rosenbaum method (coefficient of repeatability 1.0–1.2 mm).

Conclusions:

• The Rosenbaum method exhibits significant overestimation and inter-rater bias, limiting its suitability for precise pupil size measurements.
• The large agreement range between methods suggests potential inaccuracies in clinical settings.
• Findings impact the reliability of clinical trials using Rosenbaum pupillometry, particularly in refractive surgery evaluations.