VR-SFT: Reproducing Swinging Flashlight Test in Virtual Reality to Detect Relative Afferent Pupillary Defect

TL;DR

This paper introduces VR-SFT, a virtual reality-based method to objectively perform the swinging flashlight test for detecting relative afferent pupillary defects, aiming to improve reliability over traditional subjective assessments.

Contribution

The paper presents a novel VR-based approach to reproduce the swinging flashlight test, reducing variability and increasing objectivity in diagnosing pupillary defects.

Findings

VR-SFT provides consistent measurements across different observers.

The method reduces variability caused by pupil size and lighting conditions.

VR-SFT shows comparable results to traditional clinical tests.

Abstract

The relative afferent asymmetry between two eyes can be diagnosed using swinging flashlight test, also known as the alternating light test. This remains one of the most used clinical tests to this day. Despite the swinging flashlight test's straightforward approach, a number of factors can add variability into the clinical methodology and reduce the measurement's validity and reliability. This includes small and poorly responsive pupils, dark iris, anisocoria, uneven illumination in both eyes. Due to these limitations, the true condition of relative afferent asymmetry may create confusion and various observers may quantify the relative afferent pupillary defect differently. Consequently, the results of the swinging flashlight test are subjective and ambiguous. In order to eliminate the limitations of traditional swinging flashlight test and introduce objectivity, we propose a novel approach to the swinging flashlight exam, VR-SFT, by making use of virtual reality (VR). We suggest that the clinical records of the subjects and the results of VR-SFT are comparable. In this paper, we describe how we exploit the features of immersive VR experience to create a reliable and objective swinging flashlight test.