Abnormal axial elongation induced by negative optical defocus was associated with an early upregulation of AQP4 channel expression in the NFL but not in the IPL; whereas, restriction in axial elongation induced by plus lens defocus was associated with an upregulation of Kir4.1 channels in the IPL but not in the NFL later in the induction of hyperopia. Here, AQP4 is linked to hyperopia.