Final answer:
A hard blow to the back of the head is likely to affect the occipital lobe, resulting in potential visual impairments.
Step-by-step explanation:
If someone receives a hard blow directly to the back of the head, it is likely to result in damage to the occipital lobe. The occipital lobe is located at the back of the brain and is primarily responsible for vision, including seeing, recognizing, and identifying the visual world. Damage to this area can impair visual processing and could lead to vision defects or problems with visual perception.