1321 Defocus induced ametropia in chicks - role of magnification and orbital changes

Mcrhods 1) Convex (+15 D) and concave (-15 D) lenses were mounted over one eye of day old chicks (n=25). Refractive states and ocular diameters were measured by retinoscopy and ultrasound. The eyes were enucleated, weighed and measured after the birds were sacrificed on the 7th day. The remaining heads were cleaned and placed in 2% NaOH to rem& all soft tissues.Orbital dimensions were measured to 0.01 mm with vernier calipers. 2) Day oli -hicks (n=13) were treated unilaterally for seven days Gith afocal gbggles designed to produce 10% retinal image magnification, an amount comparable to the magnification produced by +lOD lenses used to induce 10D of hyperopia. Eye diameters and refractive states were measured during the experiment while the eyes were weighed and measured after the chicks were sacrificed on the 7th day.