Malformations of the eye in the exencephalic tail-short mice during its development

Exencephalic tail-short (Ts/+) embryos were obtained from mating normal mice of Patch strain with Ts/+ mice from Babl/c strain. The most common eye malformations in the exencephalic embryos were exophthalmy, microphthalmy, eye ball irregularity and corneal opacity. Squint eye and unilateral anophthalmy occurred at a lower frequency. The eye abnormalities were recognized histologically by 11-days of gestation. The retina was retarded in development. Lens fibres were swollen and some of them appeared degenerated. Lens epithelium was protruded anteriorly, detached from the underlying lens and joined the corneal endothelium. The lens remained in close contact to the ectodermal layer, forming a thick lens stalk. At the 16-day stage, the corneal epithelium became irregular in thickness and the corneal stroma was discontinuous, having disarranged collagenous fibrils. In a few embryos the corneal endothelium was absent. In the squint-eyed embryo, the cornea bulged through the opened eyelids, while in an anophthalmic embryo it was thick and underdeveloped. Generally, the upper and lower eyelids of the exencephalic embryos were asymmetrical, and the lower lid appeared covered by a thick irregular peridermal layer.