The effect of unilateral disruption of the centrifugal visual system on normal eye development in chicks raised under constant light conditions.

The centrifugal visual system (CVS) comprises a visually driven isthmic feedback projection to the retina. While its function has remained elusive, we have previously shown that, under otherwise normal conditions, unilateral disconnection of centrifugal neurons in the chick affected eye development, inducing a reduced rate of axial elongation that resulted in a unilateral hyperopia in the eye contralateral to the lesion. Here, we further investigate the role of centrifugal neurons in ocular development in chicks reared in an abnormal visual environment, namely constant light.

Disruption of the centrifugal visual system inhibits early eye growth in chicks.

Purpose: Emmetropization, the process by which neonatal refractive errors are reduced toward zero, is partially dependent on brain-retina connectivity. Here, we investigated the role of the centrifugal visual system, a visually driven retinal feedback projection, as one potential influence on this complex mechanism.

Methods: Lesions of the isthmo-optic nucleus/tract or sham surgeries were performed in fifty-four 4- to 5-day-old chicks to disrupt centrifugal efferents to the contralateral retina.