Altered Reality: The Role of Immersive Technologies in Visual Disabilities Rehabilitators Training.

In 2014 the number of people affected by visual impairments (VIs) was estimated to be 285 million, of whom 39 million were totally blind and 19 million were children below the age of 15. Compared to hearing and touch, vision provides the most precise spatial information about the distal environment. Consequently, individuals with VIs might present a delayed or impaired development of spatial capabilities. Many people who are registered as blind nevertheless retain some residual vision and are said to have “low vision”. Examples of conditions resulting in low vision are cataracts, diabetic retinopathy, age-related maculopathy, glaucoma, and hemianopsia. The exact form of VIs varies according to the medical condition it results from; usually, low vision individuals (LVIs) experience an extreme loss of perception of high frequencies resulting in gross blurring and distortion of the visual scene over a significant area of their visual field (VF). Due to this wide variety of symptoms, it is obviously hard for visual disabilities rehabilitators (VDRs) to imagine how LVIs perceive the environment. This inevitably causes “gaps” in the rehabilitator training path. In fact, the World Health Organization (WHO) reported the need to train qualified rehabilitators to fill the gaps in low-vision rehabilitation training. Moreover, the European project oMERO which aimed at creating a specific curriculum for low-vision rehabilitation, emphasized training ophthalmologists through immersive technologies capable of inducing a sense of immersion and presence. This PhD’s project was raised with the specific purpose of filling these gaps. Perceiving and navigating the world as LVIs has the potential to be a useful tool for ophthalmologists and VDRs to increase empathy with the assisted population and to improve the existing therapeutic techniques. Additionally, by analyzing ocular movements acquired during experimental sessions with healthy-sighted individuals in a condition of simulated low vision, researchers can collect quantitative data to extend their understanding of behavioural changes in LVIs. Investigating the possibility of immersive technologies to improve visual rehabilitation training is the focus of my research. Specifically, the goals of my PhD consisted of: i) design an immersive system capable of realistically simulating conditions of low vision in terms of appearance and behaviour for VDRs’ training; ii) perform quantitative evaluations to assess the immersive system’s capabilities to reproduce the "altered" eye movement by creating LVIs digital twins. In order to achieve my objectives, the first part of my research consists of designing and developing a fully wearable immersive system able to simulate in real-time into the real world several low vision conditions. The immersive system was assembled by using commercial device tools: a video see-through (VST) head-mounted display (HMD) with an integrated eye tracker; a pair of external cameras attached to HMD to provide gazecontingent altered/augmented reality content by a pass-through modality; a computer to host the software of simulations. By exploiting computer graphics techniques, the software can realistically simulate several low-vision conditions, such as age-related macular degeneration, glaucoma, and hemianopsia, and simultaneously acquire eye and head movements for data analysis. Considering the peculiarity of the system not to augment, but to alter the reality to recreate LVIs’s perspective, I coined the term alTered Reality (TR). Each simulation was validated in terms of appearance and behavior by ophthalmologists and VDRs of the Chiossone Foundation for Blind and Visually Impaired People in Genoa, who took part in every phase of the design process as project partners. Secondly, I focused on the construction of a data analysis system capable of detecting from eye tracker data the nature of eye movements, especially saccades and fixations. The analysis of eye movements was essential to conduct quantitative analysis with the system. Finally, a quantitative assessment of the system was required for scientific validation. My goal was to investigate TR’s capability to induce the alterations in the oculomotor system detected in related studies on LVIs in healthy individuals. To achieve this goal, I conducted an experimental session in which healthy individuals had to complete daily life tasks such as reading a text, pouring water from one bottle to another, and performing interactions with specific objects; each task had to be completed in three different simulated visual conditions: binocular maculopathy, homonymous hemianopsia, and tubular vision. Specifically, I analyzed task performance, eyes, and head movements in each task for each visual condition. The main findings of this study pointed out that TR can effectively induce behaviours in healthy individuals that resemble those observed in LVIs. Indeed, participants with simulated binocular maculopathy exhibited unstable fixations and a high number of wide saccades. Those with simulated homonymous hemianopsia displayed a trend of keeping their head fixed while performing wide saccades to scan the environment in the direction of the impaired hemifield. Tubular vision simulation resulted in a significant decrease in saccade amplitudes. My research project provides evidence that immersive technologies can be implemented in visual rehabilitation facilities in an attempt to meet the need for qualified rehabilitation professionals to apply new user-centred and transdisciplinary approaches, as well as an investigation tool for better insight into low vision conditions in research institutes.