There are blind spot in each eye.
Blind spot, small portion of the visual field of eacheye that corresponds to the position of the optic disk (also known as the optic nerve head) within the retina. There are no photoreceptors (i.e., rodsor cones) in the optic disk, and, therefore, there is no image detection in this area. The blind spot of the right eye is located to the right of the centre of vision and vice versa in the left eye. With both eyes open, the blind spots are not perceived because the visual fields of the two eyes overlap. When u close one eye and focus on object and move it closely,thenat some point the object bevome invisible . Thus is because the light from object falls into the optic disk
So we can t see the object and that is the blind spot