Leader Dogs for the Blind - Retinitis Pigmentosa 

This particular video is showing what a person with Retinitis Pigmentosa (RP) might experience.
RP is a rare degenerative disease that affects the retina’s ability to respond to light. This inherited disease causes a gradual decline in vision because photoreceptor cells (rods and cones) die. As RP progresses, the field of vision narrows causing “tunnel vision” until only central vision remains.