The reason that retinal detachment is so critical is that it is a potentially blinding disease. The retina depends on two blood supplies to function properly and allow one to see. The first blood supply is within the retina. The second is on the back wall of the eye.
Internalisation (or internalization) in sociology and other social sciences is the process of acceptance of a set of norms and values established by people or groups which are influential to the individual through the process of socialisation.
socialize verb (GO OUT) B2 [ I ] to spend time when you are not working with friends or with other people in order to enjoy yourself: I tend not to socialize with my colleagues. I hope Adam's actually doing some work at college - he seems to spend all his time socializing!