Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. It only takes a minute to sign up.
Sign up to join this community
I have myopia and I read that the rays of light intersect before the retina.
When I can not see clearly I can push somehow my eye muscles and can see a bit clearly. The object gets clear but moves some distance ahead (getting smaller).
My question is: What is in fact happening to the eyeball? Do the eye muscles contract it and make it more round than ellipsoid thus bringing the retina forward so the light intersects on it?
In fact I have the feeling that the eye ball gets longer (ellipsoid).
Do you mean squinting? Any sort of tension on the eyes would result in changing of the shape of the eye. A change in shape will bend light differently. The perceived effects you're describing are most likely from you changing the shape of your eyeball to take in more light.
In terms of squinting, eye strain like that won't lead to blindness or worse vision. There's more danger with UV from the sunlight (cataracts) or getting wrinkles from squinting too much in the long-run.
