None listed
Conditions
Brief summary
This project constitutes the pilot study of a direct-to-brain Bionic Eye. In this study, up to 3 blind participants will have four small devices placed over the area of the brain responsible for vision. This area is called the visual cortex, which is located at the back of the brain. Each device contains an array of microelectrodes (which are like tiny wires as thin as strands of hair) and electronic circuitry that is capable of delivering small electrical pulses to the brain via the microelectrodes. The devices are powered and controlled wirelessly, so no wires need to be implanted. When the visual cortex is electrically stimulated, small points of light are seen by the participant, which can be assembled into basic images after adequate training. This study aims to teach blind participants to ‘see’ using these basic images, thereby demonstrating the safety and utility of the direct-to-brain Bionic Eye.
Interventions
This is the First-In-Human trial of a visual prosthesis developed by Monash Vision Group. The device, which comprises an array of 43 microelectrode and wireless circuitry encapsulated in a hermetically sealed ceramic case, shall be implanted in the primary visual cortex of up to three blind participants based upon participant-specific MRI and CT-derived data. Up to four devices are to be implanted in each participant, in a procedure that will last approximately two hours. The implantation proced
This is the First-In-Human trial of a visual prosthesis developed by Monash Vision Group. The device, which comprises an array of 43 microelectrode and wireless circuitry encapsulated in a hermetically sealed ceramic case, shall be implanted in the primary visual cortex of up to three blind participants based upon participant-specific MRI and CT-derived data. Up to four devices are to be implanted in each participant, in a procedure that will last approximately two hours. The implantation procedure is to be performed by an experienced neurosurgeon who is familiar with the approach to the occipital lobe, where the Primary Visual Cortex is located. Once implanted, the devices will be powered and controlled wirelessly to deliver small electrical currents to the Primary Visual Cortex, which is expected to evoke visual percepts in the participant's visual field, called ‘phosphenes’. In addition to the implantation procedure, this trial involves a two year training program, during which the participants will learn to construct simple images from the phosphenes created by the device. These images will be controlled by the researchers by delivering pulse trains of variable amplitude, duration, frequency, pulse timing and duty cycle from the microelectrode arrays, within the safety limits of the device. Participants are required to attend one full day of training per week at Monash University (up to 8 hours, including breaks). The program begins with very simple tasks, which involve the participants describing the location and brightness of each phosphene that can be evoked. Psychometric curves for every phosphene will be characterised, and the spatial location will be mapped on a log-polar plot. More complex tasks, such as construction of images from contiguous phosphenes, will be attempted as the participant learns to interpret the visual data that is delivered. These tasks will be conducted in one on one sessions where the participant is seated, and the devices are controlled via a custom-designed headset worn by the participant. The headset creates a magnetic field that controls the devices wirelessly, thereby eliminating the need for any wires into the body. If participants successfully learn to recognise objects in these simple tasks, then they will be given a portable adaptation of the system to use in navigational tasks. These tasks are designed to emulate real life situations, such as independently navigating a space or locating an object in a room. The purpose of these tasks is to allow the researchers to develop the device for take home use. However, a take home system is not within the scope of this study, and participants cannot take the portable system home. Throughout the study, all results will be recorded in a descriptive manner, based upon the participant’s descriptions of what they see. Phosphene evocation thresholds will be determined for various pulse train parameters to determine the optimal settings for each participant. In addition, the proficiency with which participants complete tasks shall be recorded to determine any improvement over time.
Sponsors
Monash University
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
Untreatable bilateral complete vision impairment in the entire visual field due to any of the following (non-comprehensive): Glaucoma, Age-related Macular Degeneration (AMD), Retinitis pigmentosa (RP), Acquired retinal disease where there is no ability to place a retinal implant, Severe vitreous disease which is uncorrectable and results in blindness, Optic nerve disease and degeneration (e.g. severe optic neuritis, Devic's disease), Hereditary Optic Neuropathies, Inherited forms of optic nerve degeneration (e.g. Leber's hereditary optic neuropathy), Severe trauma to both eyes and or optic nerves, Enucleation of the eyes due to bilateral retinoblastoma, Sellar (pituitary) and parasellar tumours with optic chiasm compression, Pituitary apoplexy, or Pituitary bed haemorrhage with postoperative blindness.
Exclusion criteria
Residual vision, History of traumatic occipital cortex injury, Poor mobility with high falls/fracture risk, Psychiatric, psychological or neuropsychological disorders, History of chronic disease, including insulin-dependent diabetes mellitus, renal, liver or respiratory disease, Epilepsy, moderate to severe hypertension, arrhythmia, valvular disease, ischaemic heart disease, coagulation disorders, HIV, hepatitis B and C, or receiving or have a requirement for any of the following medication: Anticoagulant therapy (e.g. warfarin), Immunotherapy (e.g. monoclonal antibodies, corticosteroids), or Hormone replacement therapy.
Outcome results
None listed