Eye Abnormalities in Mouse Fetuses Caused by Simultaneous Irradiaition of X-Rays and Ultrasound. 2. Developmental Abnormalities of the Eye

Abstract

Eye abnormalities in mouse fetuses caused by irradiation of 150 R of x-rays alone, or simultaneous irradiation of 150 R of x-rays and ultrasound at 1.5 or 3 W/cm^2 for 5 min on day 7 of gestation were histologically studied on day 18 of gestation. Most abnormal eye findings were similar to x-ray induced ones earlier reported by many investigators, but some interesting ones were revealed in the present experiment. Abnormalities of the primary vitreous corresponding to persistent hyperplastic primary vitreous encountered clinically were detected. In these cases, excessive mesenchymal tissue was present in the vitreous cavity, some pulling the retina partially. The defective iris similar to the atypical iris coloboma or corectopia was also noticed. In the fetuses with aplasia of the optic nerve, hyaloid artery, optic disc and optic chiasma were absent, but some retinal ganglion cells presented. Aberrant optic nerve fibers were detected in one or another of the iris, the cornea, the anterior chamber, the space between two layers of the optic cup or the vitreous cavity. It was considered that the pathogenesis of this abnormality consisted in the defective formation of the fetal fissure due to abnormal invagination of the optic vesicle. In the fetuses with hypoplasia of the optic nerve, a part of the optic nerve fibers were disoriented and did not reach the optic disc, although the hypoplastic optic disc was present at the normal position.