3 ms·

Yeah typo. The theory is that eyes change shape over time (I think starting out longsighted) and at some point a hormone is released to stop this changing. It i

Yeah typo. The theory is that eyes change shape over time (I think starting out longsighted) and at some point a hormone is released to stop this changing. It is released when (a) the eyes are typically around the middle of their focal range (ie looking at middle-distance things is done with relaxed eyes) and (b) there is a lot of light. Without the second condition the shape of the eyes will continue to change and then you get myopia.

derefr 4y ago
See also: metabolic bone disease in lizards. Also caused by a lack of light — in their case, near-UV light. (My understanding is that the thing changing the shape of the eye over time is the development of the orbital socket bones — so nearsightedness and MBD could have more in common than it seems.)