Effects of virtual reality usage on kappa angle, accommodation, pupil, depth perception, and examination of the relationship of these parameters with discomfort perception

Year 2024, , 59 - 62, 28.01.2024

Volkan Dericioğlu , Betul Kubat

https://doi.org/10.5472/marumj.1378508

Abstract

Objective: This study aims to examine the effects of virtual reality (VR) usage on the eyes and investigate the parameters responsible
for the subsequent discomfort sensation.
Materials and Methods: This prospective study enrolled 20 healthy volunteers who were engaged in a 10-minute VR game session.
Refractive errors, kappa angles, phoria presence, accommodative responses, and scotopic, mesopic, and photopic pupillometry values
were recorded before and after using VR. A Virtual Reality Sickness Questionnaire (VRSQ) was applied to assess discomfort, and the
relation with evaluated parameters was investigated.
Results: Twenty volunteers (mean age 29.80±0.57 years) included 11 females (55%) and 9 males (45%). The mean spherical equivalent
refractive error was – 1.94±0.28 diopters and 5 (25%) volunteers had phoria. Average kappa angles were 0.23±0.02 mm (x-axis) and
0.11±0.01 mm (y-axis). Post-VR, the median [(interquartile range (IQR)] stereopsis decreased from 30 (30-60) to 60 (60-60) arc
seconds (P<0.001). Pupil sizes increased significantly across all lighting conditions (P<0.001). Accommodation did not significantly
change post-VR (P>0.05). VRSQ scores correlated positively with phoria and kappa-x angle (r=0.458, P=0.003 and r=0.330, P=0.038)
while negatively with stereopsis and kappa-y angle (r=-0.375, P=0.017 and r=-0.326, P=0.04).
Conclusion: Virtual reality use reduces depth perception and induces significant mydriasis across lighting conditions. Post-VR
discomfort feeling may be related to phoria, kappa angle, and stereopsis.

Keywords

Virtual reality, Accommodation, Kappa, Stereopsis, Pupillometry

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