Visual cortical thickness increases with prolonged artificial vision restoration.

Abstract

The Argus II retinal prosthesis restores visual perception to late blind individuals. It has been shown that structural changes occur in the brain due to late-onset blindness, including cortical thinning in visual cortical regions. Following vision restoration, it is not yet known whether visual regions are reinvigorated and regain a normal cortical thickness or retain the diminished thickness from blindness. We evaluated the cortical thicknesses of 10 Argus II participants, 10 blind participants, and 13 sighted participants. The Argus II patients on average had a thicker left cuneus cortex and lateral occipital cortex relative to the blind patients. The duration of the Argus II use significantly partially correlated with thicker visual cortical regions in the left hemisphere. Furthermore, in the 2 case studies (scanned before and after implantation), the patient with longer device use (44.5 months) had an increase in the cortical thickness of visual regions, whereas the shorter-using patient did not (6.5 months). Overall, the Argus II participants' cortical thickness was on average significantly rejuvenated in 2 higher visual regions, and participants using the implant for a longer duration had thicker visual regions. This research raises the possibility of structural plasticity reversing visual cortical atrophy in vision restoration participants.