Visual Rehabilitation in Children With Homonymous Hemianopia: a Pilot Study on Virtual-reality Stimulation

A brain tumor and its treatment can affect the visual system at different levels, from the optic nerves (through compression or infiltration). Children with brain tumors can present visual impairments like decreased visual acuity and contrast sensitivity, loss of color vision, and visual field loss such as hemianopias. Patients with hemianopia present difficulties in detecting stimuli in the defective visual field and show defective scanning and exploration. Moreover, they show a rotation and compression of the auditory space leading to imprecise localization of sound across both hemispaces. Patients with hemianopia naturally develop oculomotor strategies to compensate for visual field loss, but visual rehabilitation procedures must still be developed to optimize/improve visual perception in the blind field. Several studies demonstrated that these patients could improve visual perception in the damaged hemifield after a stimulation procedure where auditory and visual stimuli were temporally and spatially correlated. Such audiovisual stimulation programs induce a functional and anatomical reorganization of the visual connectivity in subcortical and cortical structures over time.

The current strategies rely on a significant workload, over 30 hours of audiovisual stimulation using static, spatially, and temporally coherent stimuli displayed on large screens/panels in a clinical setting. These strategies require frequent visits to the clinic impeding the patients' adherence and compliance and increasing the burden of disease. We seek to develop an audiovisual stimulation procedure using immersive virtual reality (IVR) using a head-mounted display (HMD). This is an emerging and very promising visual rehabilitation approach using high-technology devices. It is developed to provide sensory stimulation with better ecological validity due to virtual reality, greater flexibility due to home-based programs, and improved efficiency due to patient-tailored protocols. IVR is a versatile technology, allowing its potential use for the rehabilitation of a variety of low-vision conditions. There are currently limited practical results on whether this technology is suitable for low-vision patients to use at home and if it can be deployed on a large scale. A few case reports/series studies suggested the potential effectiveness of IVR on visual perception in teenagers, adults, and the elderly but more information as to the potential of use and effectiveness of this technology in children and young teenagers is necessary

Inclusion criteria

• Homonymous hemianopsia
• Male and female.
• > 8 years old
• Interpupillary distance >=56 mm
• BCVA > 20/200
• Ability to follow visual and auditory stimuli and training instructions.
• Home Wi-Fi access.

Exclusion criteria

• Ocular diseases
• Both eyes with media opacity that impairs microperimetry testing.
• Inability to perform during testing and training.
• Consumption of psychoactive drugs.
• 3 consecutive VRISE scores < 25 at inclusion.
• History of vertigo or dizziness
• Prior vision rehabilitation interventions.