# Diagnostic performance of pupil perimetry in detecting hemianopia under standard and virtual reality viewing conditions

## TL;DR

This study compares two pupil perimetry methods for detecting visual field loss in patients with neurological damage, finding them reliable and accurate under standard and virtual reality conditions.

## Contribution

The study reports the highest diagnostic accuracy of pupil perimetry in homonymous hemianopia and confirms its reliability in standard and virtual reality settings.

## Key findings

- gcFPP and VRgcFPP both show high diagnostic accuracy in separating intact and damaged visual field regions.
- Both methods demonstrate high test–retest reliability in measuring visual field defects.
- gcFPP provides cleaner imaging of visual field regions compared to VRgcFPP.

## Abstract

To determine the diagnostic performance and reliability of two pupil perimetry (PP) methods in homonymous hemianopia.

This cross-sectional monocenter cohort study performed gaze-contingent flicker PP (gcFPP) and a virtual reality version of gcFPP (VRgcFPP) twice on separate occasions in all patients suffering from homonymous hemianopia due to neurological impairment. The main outcomes were (1) test accuracy and (2) test–retest reliability: (1) was measured through area under the receiver operating characteristics curve (AUC) calculation of (VR)gcFPP results with comparators being SAP and healthy controls, respectively; (2) was evaluated by comparing tests 1 and 2 of both methods within patients.

Both gcFPP and VRgcFPP were performed in 15 patients (12 males, MAge = 57, SDAge = 15) and 17 controls (6 males, MAge = 53, SDAge = 12). Mean test accuracy was good in separating damaged from intact visual field regions (gcFPP: Mauc = 0.83, SDauc = 0.09; VRgcFPP: Mauc = 0.69, SDauc = 0.13) and in separating patients from controls (gcFPP: Mauc = 0.92, SDauc = 0.13; VRgcFPP: Mauc = 0.96, SDauc = 0.15). A high test–retest reliability was found for the proportion intact versus damaged visual field (gcFPP: r = 0.95, P < .001, VRgcFPP: r = 1.00, P < .001).

Overall, these results can be summarized as follows: (1) the comparison of pupil response amplitudes between intact versus damaged regions per patient indicate that gcFPP allows for cleaner imaging of intact versus damaged visual field regions than VRgcFPP, (2) the comparisons of average differences in intact versus damaged amplitudes between patients and controls demonstrate high diagnostic performance of both gcFPP and VRgcFPP, and (3) the test–retest reliabilities confirm that both gcFPP and VRgcFPP reliably and consistently measure defects in homonymous hemianopia.

What is known
Standard automated perimetry is the current gold standard for visual field examination, but not always suited for the evaluation of the VF in neurologically impaired patients.Pupil perimetry consists of the measurement of pupillary responses to light stimuli as a measure of visual sensitivity.

Standard automated perimetry is the current gold standard for visual field examination, but not always suited for the evaluation of the VF in neurologically impaired patients.

Pupil perimetry consists of the measurement of pupillary responses to light stimuli as a measure of visual sensitivity.

What is new
This study reports the highest diagnostic accuracy of pupil perimetry so far in patients with homonymous hemianopia.Gaze-contingent flicker pupil perimetry reliably and consistently measures defects in homonymous hemianopia under standard and virtual reality viewing conditions.

This study reports the highest diagnostic accuracy of pupil perimetry so far in patients with homonymous hemianopia.

Gaze-contingent flicker pupil perimetry reliably and consistently measures defects in homonymous hemianopia under standard and virtual reality viewing conditions.

The online version contains supplementary material available at 10.1007/s00417-024-06641-4.