The brain is complicated but what isn’t is understanding MCE. Several parts of the brain control stimuli including the frontal lobe, temporal lobe, and thalamus, amongst other parts. Since brain matter is being replaced (or has already) with cysts, there’s just no way she can do…anything meaningful
You have to think of Luna as constantly short circuiting. Nothing works. Nothing functions right except for the brain stem, cerebellum, part of the spinal cord, basal ganglia, inferior temporal lobes, and orbital surfaces of the frontal lobes
It’s been postulated that Luna is blind and I do not believe that to be the case. Why? The inferior temporal cortex is responsible for vision and that is spared in MCE, which can be visualized on imaging.
Now, even if she can see, she can’t respond, she can’t think, and so on. We do know she can’t close her eyes so she is probably incapable of eye gazing/tracking, but she should be capable of having vision.
Tl;dr she can most likely see but cannot do anything with the information