Torsional eye movement, known as cycloversion and cyclovergence have a fascinating evolutionary history via our evolutionary ancestors that had eyes on the sides of their heads. Your eyes twist in this way whenever you tilt your head!
Yup. Learned about that in my 20’s. And if the two oblique muscles that do that rotation both contract at the same time, your eyeball temporarily elongates and lets you see a bit closer. At least that’s the only explanation I have for why I could accommodate a diopter closer despite having my ciliary muscles paralyzed (temporarily) on my last eye exam.
Further, I wonder if this could be learned by astigmatics to increase clarity of reading.
My current pet theory on what causes myopia is obliques-assisted accommodation during long closeup sessions. I theorize that as the ciliaries get tired, the obliques help keep focus, and their eye elongation effect when they’re both engaged leads, over thousands of hours, to longer eyes and thus myopia.
And that we “discover” this by reading sideways, specifically when lying on a couch or bed with a book that is rotated relative to the head. The obliques counter-rotate the eyes to facilitate reading, and this creates a natural opposition between the obliques, leading to a bit of temporary eye elongation. And this eases the burden on the ciliary muscles, while simultaneously helping train the brain to use the obliques during close up accommodation.
At least, that’s my current theory as to what happens. And that explains why some never get myopia, they never figured out how to assist close up accommodation with the obliques, just like many people don’t ever learn active focus.
It’s an interesting pet theory.