ERG OF FORM DEPRIVATION MYOPIA AND DRUG-INDUCED AMETROPIA IN CHICKS

Chick eyes occluded for various periods or treated with various concen trations of kainic acid (KA) or 2-amino-4-phosphonobutylate (APB) duri ng development showed characteristic changes of electroretinography an d of refraction. In occluded eyes, oscillatory potential amplitudes (O P-A) were reduced, even with high-intensity stimulation, in proportion to duration of occlusion, but b wave amplitude was unchanged, implyin g functional changes in inner layers of the deprived retina. OP-A redu ction after only 1 week of occlusion and reversibility of this change might reflect retinal changes preceding axial elongation. KA was confi rmed to induce myopia with axial elongation and APB to induce hyperopi a with axial shortening. KA and APB both suppressed OP-A. KA reduced O N and OFF responses, but low-dose APB suppressed only ON responses. St udy results suggest that myopia could be induced by changes of inner r etina mediating OP attenuation and degradation of ON and OFF responses . This manuscript reports unpublished work that is not currently under consideration for publication elsewhere.