Final answer:
The inability to accommodate (cycloplegia) due to lesions in the oculomotor nerve (CN III) can lead to hyperopia (farsightedness) and blurred vision. To correct this problem, a convex lens is needed.
Step-by-step explanation:
The inability to accommodate (cycloplegia) due to lesions in the oculomotor nerve (CN III) can impact vision in several ways. The oculomotor nerve controls the muscles that change the shape of the lens in the eye. When this nerve is damaged, the muscles cannot pull hard enough on the edges of the lens to make it less convex, leading to a condition called hyperopia (farsightedness).
With the inability to accommodate, the images are focused between the lens and the retina, causing blurred vision. This can result in difficulty seeing objects up close.
To correct this problem, a convex lens is needed. A convex lens helps the converging light rays to focus properly on the retina, allowing for clearer vision.