Final answer:
Maximal accommodation in vision occurs under the control of the parasympathetic nervous system, which is responsible for focusing the eyes on nearby objects by changing the shape of the lens within the eye.
Step-by-step explanation:
We have maximal accommodation in our vision when the parasympathetic nervous system (PSNS) is in control. Accommodation in vision refers to a change in the ability of the eye to focus on objects at different distances, which occurs when the ciliary muscles adjust the shape of the lens. The accommodation-convergence reflex coordinates somatic control of the medial rectus muscles with the PSNS control of the ciliary bodies to maintain focus as the eyes converge on a near object.
This process is part of a range of autonomic responses that are vital for maintaining homeostasis within the body. The PSNS is responsible for decreasing pupil size – via the pupillary light response – to reduce the intensity of light reaching the retina, thereby optimizing vision in bright light conditions. Conversely, in low light conditions, the sympathetic nervous system (SNS) dilates the pupil, allowing more light to enter for better vision. This is essential for activities that require heightened alertness or for a fight-or-flight response
Thus, for maximal accommodation of the eye for near vision, activation of the PSNS is necessary.