Why puberty occurs earlier in blind people?

A hormone secreted from pineal gland(epiphysis) named as MELATONIN is responsible for this. Melatonin maintains normal rhythms of diurnal sleep-wake cycles,body temperature as well as MENSTRUAL CYCLE and PUBERTY.

MELATONIN DELAYS PUBERTY:- light reduces melatonin formation. As per L. Zacharias and R. J. Wurtman: light, acting on the neuroendocrine axis of the blind human (even one who is totally without light perception) in the absence of retinal responses to light, produces an imbalance which results in earlier menarche.People blind from birth attain puberty earlier than normal,apparently because there is no inhibitory effect of melatonin on function of gonads