Scientists at Cincinnati Children's Hospital Medical Center and the University of California San Francisco (UCSF) have identified a light-response pathway that controls the number of retinal neurons, and has effects on developing vasculature in the eye.
The unexpected findings, published in Nature, were said to offer a new basic understanding of foetal eye development and ocular diseases caused by vascular disorders, in particular retinopathy of prematurity.
Professor David Copenhagen of the departments of Ophthalmology and Physiology at UCSF, said: 'Several stages of mouse eye development occur after birth. Because of this, we had always assumed that if light played a role in the development of the eye, it would also happen only after birth.'
Researchers found that activation of a light-response pathway must happen during pregnancy to activate the 'carefully choreographed programme' that produces a healthy eye.
They specifically found it was important for a sufficient number of photons to enter the mother's body by late gestation - or about 16 days into a mouse pregnancy.
Researchers also observed that photons of light activated a protein called melanopsin directly in the foetus - not the mother - to help initiate normal development of blood vessels and retinal neurons in the eye. In the experiments, mice were reared in the dark and in a normal day-night cycle beginning at late gestation to observe the comparative effects on vascular development of the eye.