Final answer:
The blind spot in the visual field is caused by the absence of rods and cones in the optic disc, where the optic nerve exits the eye. The brain compensates for this blind spot by filling in the missing information from the surrounding areas of the visual field.
Step-by-step explanation:
The blind spot in the visual field is due to the optic disc, where the optic nerve exits the eye. This area does not have any rods or cones, the cells responsible for detecting light. Therefore, when an object is focused on the blind spot, the brain does not receive any visual information, resulting in a blind spot in the visual field. However, we do not usually notice this blind spot as the brain fills in the missing information from the surrounding areas of the visual field.