ERG of form deprivation myopia and drug induced ametropia in chicks.

Chick eyes occluded for various periods or treated with various concentrations of kainic acid (KA) or 2-amino-4-phosphonobutylate (APB) during development showed characteristic changes of electroretinography and of refraction. In occluded eyes, oscillatory potential amplitudes (OP-A) were reduced, even with high-intensity stimulation, in proportion to duration of occlusion, but b wave amplitude was unchanged, implying functional changes in inner layers of the deprived retina. OP-A reduction after only 1 week of occlusion and reversibility of this change might reflect retinal changes preceding axial elongation. KA was confirmed to induce myopia with axial elongation and APB to induce hyperopia with axial shortening. KA and APB both suppressed OP-A. KA reduced ON and OFF responses, but low-dose APB suppressed only ON responses. Study results suggest that myopia could be induced by changes of inner retina mediating OP attenuation and degradation of ON and OFF responses. This manuscript reports unpublished work that is not currently under consideration for publication elsewhere.