EFFECTS OF SOFT-X-RAY IRRADIATION ON OCULAR DEVELOPMENT IN SPRAGUE-DAWLEY RATS

Pregnant rats were irradiated with soft x-rays at a dose of 1.6, 3.2, 6.3 or 12.6 Gy on Day 9 of gestation, and the eyes of F1 offspring were examined using indirect ophthalmoscopy and biomicroscopy during Postnatal Week 5. Ophthalmoscopic examination revealed iris and choroidal coloboma, microphthalmia and anophthalmia in the 3.2, 6.3 and 12.6 Gy groups. In addition to those anomalies, lens luxation and associated anterior displacement of the vitreous face, and retinal vascular anomalies were observed in the 12.6 Gy group. Histological examination revealed agenesis of retinal vessels. Ophthalmoscopic examination using biomicroscopy and indirect ophthalmoscopy detected choroidal coloboma, lens and vitreous luxation and defect in retinal vessels which could not be detected by external observation, demonstrating the usefulness of this technique in the postnatal stage of teratology studies.