Optimisation of a VR-based OKAN Test with Eye Tracking for PPPD Diagnosis

We developed a VR-based OKAN test with integrated eye tracking to replace the traditional physical optokinetic drum. It is designed to improve PPPD diagnosis by increasing patient compliance, guiding operators through a clear workflow, and simplifying data analysis for experts.

Demonstration video of the OKAN-VR_V2.0 system showing the test workflow, patient view in VR, and automated report generation.

Initial situation

PPPD is a rare but complex vestibular disorder that is difficult to diagnose objectively. Current clinical practice relies mainly on patient self-reports, as standardised measurement tools are limited. The OKAN test — measuring eye movements after a rotating visual stimulus — shows promise as an objective method. The first VR prototype (OKAN-VR_V1.0) replicated this procedure virtually, but had shortcomings in patient compliance, operator usability, and the efficiency of data processing.

Problem statement / Project goal

The goal was to create OKAN-VR_V2.0, a VR-based medical test system that:
– Encourages patients to complete the test correctly, improving result quality.
– Guides operators through each step to reduce procedural errors.
– Automatically processes and visualises test data so experts can analyse results faster and more accurately.

Solution developed and its benefits

Our application is a VR-based medical testing system that replaces the traditional physical optokinetic drum and is designed to support the diagnosis of PPPD. During the test, the patient wears a VR headset that displays a rotating scene, triggering optokinetic nystagmus (OKN). At a defined point, the scene fades to darkness, allowing the measurement of the optokinetic after-nystagmus (OKAN). Integrated eye tracking records these movements in real time. The operator uses an intuitive interface with a clear, guided workflow, can monitor exactly what the patient sees, and can intervene immediately if the patient makes a mistake — minimising invalid tests. Once the test is completed, the system automatically processes the data and generates a report. This report provides both a concise summary for quick assessment and detailed data views for in-depth analysis by medical experts.

• Redesigned operator interface to improve guidance and usability.
• Live patient monitoring to detect and correct mistakes during the test.
• Additional VR scenes optimised for comfort and measurement quality.
• Automated report creation to simplify and speed up data analysis.
• Reports providing both a quick summary and detailed data views.

Benefits: Higher rate of valid tests compared to the original prototype. Faster and simpler analysis for experts. Reduced patient burden by avoiding unnecessary repetitions. A ready-to-use platform for further clinical research and refinement of PPPD diagnostic parameters.

Key terms

• PPPD Persistent Postural-Perceptual Dizziness
• OKAN Optokinetic After-Nystagmus
• OKN Optokinetic Nystagmus
• Eye Tracking Real-time measurement of eye movements
• VR Virtual Reality-based testing environment

Customer

MachineMD
Samuel Schenk (MachineMD)
Prof. Dr. Giovanni Bertolini (Institute of Optometry FHNW, PPPD Expert)
Dr. med. Marie Reynders (Researcher, PPPD Expert)

Team