Retinal and tectal potentials to alternating gratings were recorded in pigeons raised monocularly deprived. Deprived eyes showed consistent myopia and anterior-posterior axis elongation. In addition, vitreal opacities were observed in 70% of the deprived eyes. In pigeons with vitreal opacities, a reduction of retinal and tectal response amplitude was consistently found in the high spatial frequency range. Pigeons with clear media of the deprived eyes showed normal retinal and tectal responses.