# Pointing at static targets in a virtual reality environment: performance of visually impaired vs. normally-sighted persons

Vasiliki Myrodia, Aurélie Calabrèse, Ambre Denis-Noel, Frédéric Matonti,
Pierre Kornprobst, Eric Castet

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## To cite this version:

Vasiliki Myrodia, Aurélie Calabrèse, Ambre Denis-Noel, Frédéric Matonti, Pierre Kornprobst, et al. Pointing at static targets in a virtual reality environment: performance of visually impaired vs. normally-sighted persons. VSS 2023 - Vision Sciences Society, May 2023, St. Pete Beach, Florida, United States. hal-04147438

HAL Id: hal-04147438

https://inria.hal.science/hal-04147438

Submitted on 30 Jun 2023

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## Introduction

The pointing task mobilizes visuo-attentional and oculomotor functions. Our hypothesis is that it could be a good rehabilitation tool. We have developed this pointing task as an exploratory experiment in which we try to know if the patients manage to do it.

## Question

How can a visually impaired person with central vision impairment perform a pointing task with the head in a virtual environment?

## Method

### Virtual Reality & Microperimetry

Subjects must point at the target using a reticle that moves with the head. This study is developed with PTVR, an open-source VR toolbox (https://ptvr.inria.fr/).

<figure><img src="image_3.png" /><figcaption>Figure 1. Trial procedure</figcaption></figure>

### Reticle

<figure><img src="image_4.png" /><figcaption>Figure 2. Reticle in central position and all target positions</figcaption></figure>

The reticle has 2 conditions centered or eccentric of 10° from the center. An eccentric reticle has 8 possible positions on the 8 half-meridians.

### Participants

$$N = 36$$

- 20 visually impaired (mean age = 79)
- 16 normally sighted persons (mean age = 64)

## Discussion

The virtual reality was well received by the visually impaired subjects. Results show a significant difference in performance between patients and normally-sighted persons. An effect of the activation radius on the reaction time is observed as well.

## Results

### Virtual Reality

<figure><img src="image_5.png" /><figcaption>Figure 3. The effect of the activation radius on the reaction time</figcaption></figure>

<figure><img src="image_6.png" /><figcaption>Figure 4. Reaction time & accuracy averaged across patients</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>Figure 5. Average reaction time for a patient</figcaption></figure>

### Microperimetry

<figure><img src="image_8.png" /><figcaption>Figure 6. Six cases of patients, each image shows the color fundus image, the fixations and the stimulus pattern</figcaption></figure>

### Perspectives

- Analyze the performance of patients as the function of their scotoma characteristics.

- Monocular vision experiment.