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 wer
e examined using indirect ophthalmoscopy and biomicroscopy during Post
natal 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 a
nterior displacement of the vitreous face, and retinal vascular anomal
ies were observed in the 12.6 Gy group. Histological examination revea
led agenesis of retinal vessels. Ophthalmoscopic examination using bio
microscopy and indirect ophthalmoscopy detected choroidal coloboma, le
ns 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.