Refractive-error changes in kitten eyes produced by chronic on-channel blockade.
The dependence of the emmetropization process on retinal ON-channel activity was examined in developing kittens by making regular intravitreal injections of D,L-2-amino-4-phosphonobutyric acid (APB). In comparison to sham-injected control eyes, the APB-treated eyes had shorter axial lengths and were more hyperopic. Since chronic atropinization did not alter the development of the APB-induced hyperopia, these anomalous refractive errors are not the result of altered accommodative function. The axial hyperopia observed in the APB-treated eyes indicates that the mechanisms responsible for normal axial elongation are dependent to some extent on ON-channel activity and that, even in the presence of a clear retinal image, OFF-channel activity, by itself, is not sufficient to regulate the normal emmetropization process.
Smith
E L
EL
College of Optometry, University of Houston, TX 77204-6052.
Fox
D A
DA
Duncan
G C
GC
D000613:Aminobutyrates / Q000633:toxicity*; D000818:Animals; D000831:Animals, Newborn; D001285:Atropine / Q000633:toxicity; D002415:Cats; D005074:Evoked Potentials, Visual / Q000502:physiology; D012030:Refractive Errors / Q000139:chemically induced* / Q000473:pathology; D012160:Retina / Q000473:pathology; D013997:Time Factors; D014793:Visual Cortex / Q000502:physiology
D000613:Aminobutyrates; D001285:Atropine; C012729:2-amino-4-phosphonobutyric acid