Repeatability of Pupil Size Measurements Using a Multimodal Diagnostic Device

Abstract

Purpose : Assessment of pupillometry holds crucial significance in many clinical and research applications, including the diagnosis of disease through the observation of pupil abnormalities and the monitoring of pupillary reflexes in response to therapeutic interventions. This prospective study investigates the intrasession repeatability of pupil size measured with a multimodal diagnostic device.

Methods : 10 adults (aged 24-77) with a total of 19 healthy eyes were evaluated. Visual acuity and slit lamp examination were assessed to ensure the absence of ocular media obstruction and concomitant pathology. Subjects underwent a comprehensive eye exam. Using the MYAH (Topcon Healthcare/VISIA, San Giovanni Valdarno, Italy) under dynamic (variable) light conditions, minimum (i.e. photopic) and maximum (i.e. scotopic) pupil sizes were measured for each eye. Subsequently, pupil sizes were measured under static photopic, mesopic, and scotopic light conditions. This sequence of five measurements was repeated three times per eye. The repeatability standard deviation (s_r) and coefficient of repeatability (CoR) were calculated to assess the intrasession variability of MYAH pupillometry readings measured in each study eye (Table 1).

Results : The s_r for photopic (minimum) pupil size measured using dynamic pupillometry was 0.28 mm, while the s_r for scotopic (maximum) pupil size was 0.23mm. In assessing the repeatability of static pupillometry, the s_r for mesopic pupil size (0.26) was higher than that for both photopic (0.19) and scotopic (0.18) pupil measurements. Analysis of the CoR revealed the highest repeatability in pupil size readings measured under scotopic settings compared to mesopic and photopic settings. CoR was lowest in the static scotopic setting (3.3%), followed by the dynamic scotopic setting (4.1%), static mesopic (5.6%), static photopic (6.0%), and highest in the dynamic photopic setting (10.3%).

Conclusions : This preliminary evidence supports excellent intrasession repeatability for pupillometry measurements conducted under both static and dynamic light conditions using the MYAH device. Evaluation of pupil size under scotopic light settings revealed the least variability in measurements when compared across the five modalities of data capture (dynamic photopic, dynamic scotopic, static photopic, static mesopic, static scotopic).

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Table 1. Intrasession repeatability of pupil size measured with MYAH under various light levels