Why can your retina detach?
If the retina is grown on the back of the eye, as a part of the back of the eye, why does it seem to detach so easily, under different conditions?
Basically, there is a natural anatomical cleavage plane between the retina, which is a nervous tissue, and the pigmented layer, which is the back of the eye. Retinal detachment is a different situation. That's when a hole develops in the retina, and fluid goes in between that space and the retina collapses, very much like having a puncture in an inner tube, the retina collapses down. Unfortunately that's just a natural property of the way the eye's been made.