Indeed. It's all very interesting stuff, but very difficult to know what is going on sometimes. The telemetry from the spine is complex, but nothing compared to the brains ability to gather information from the eyes.
People with poor eyesight are able to do things that a linear logic of visual performance would prohibit. The brain works round all sorts of difficulties. It is how it does it that causes other problems sometimes.
I am personally convinced that the brain can use the extra-ocular muscles to facilitate focusing, but I haven't really made much effort to find any published work on this phenomenon.