Glaucoma occurs in several animal species including man. In animals glaucoma has been investigated primarily in the rabbit as a biomedical research animal, in the nonhuman primate for posterior segment studies, and in the dog as a clinical patient and potential animal model. Primary glaucoma in the different animal species suggests genetic predisposition. As the aqueous humor pathways of the different animal species possess more anatomic and physiologic similarities than differences, studies of the glaucomatous trabecular meshwork of each animal species may provide additional information about the genesis of increased outflow resistance and new forms of therapy for all species including man.

The congenital and acquired ophthalmic diseases of the foal range from microphthalmia, entropion, and corneal ulcers to cataracts, and retinal detachments. Ophthalmic examinations of foals soon after birth with slit lamp biomicroscopy, applanation tonometry, direct and indirect ophthalmoscopy are important to detect and establish a rapid diagnosis, and initiate the appropriate therapy. These congenital and acquired conditions are important to identify, treat if necessary, and eliminate those disorders that may be inherited. Many of the ophthalmic disorders affecting the conjunctiva, iris, and ciliary body are associated with serious systemic diseases that require early recognition and vigorous treatment. Variations in the normal lens and ocular fundus of foals are important to recognize and differentiate from the actual disease conditions.

The corneas of nine strains of laboratory mice were histologically examined at 10 and 26 weeks of age. No corneal lesions were detected in any of the ICR or ICR-n/+ mice. There was low incidence of corneal lesions in C57BL/6, BDF₁, and B6C3F₁ mice. Higher incidence of corneal lesions was observed in BALB/cAn, C3H/He, DBA/2, and ICR-n/n mice. The incidence of corneal lesions in both sexes of C3H/He mice and in females of BDF₁, B6C3F₁, BALB/cAn, and C57BL/6 mice was higher at 26 weeks of age than at 10 weeks of age. Corneal lesions in BDF₁, B6C3F₁, BALB/c, C57BL/6, C3H/He, and DBA/2 mice were characterized by deposition of basophilic material in Bowman's membrane, and degeneration of collagen fibers, proliferation of fibroblasts, vascularization, and infiltration of mononuclear cells in the corneal stroma. Corneal lesions of ICR - n/n mice were caracterized by infiltration of neutrophils and mononuclear cells as well as vascularization in the corneal stroma. Thickness of the corneal epithelial layer and number of the epithelial cell rows in all strains of mice decreased at 26 weeks of age compared with those at 10 weeks of age. There were marked differences in thickness of the corneal epithelial layer among different strains of mice at any given age. These results suggest that the development of corneal lesions in mice may be related to genetic factors and aging.

Many animal models have been established to explain the mechanism of human cataract development, but none are satisfactory. In 1989, a female Sprague-Dawley rat which developed a spontaneous cataract was found in the colony at Upjohn Pharmaceuticals Limited, Tsukuba Research Laboratory. The cataract was shown to be hereditary by sister-brother matings. Cataracts in rats are classified into two types according to the age of cataract formation, early-onset type and late-onset type. Rats with early-onset cataracts have lens opacification before eye opening, and often also have microphthalmos, microphakia, proptosis, and synechia. Rats with late-onset cataracts start to develop lens opacification from about 7 weeks of age. Abnormally elongated epithelial cells are observed histologically in both cataract types. From our results to date, we hypothesize that this cataract has autosomal intermediate or incomplete dominant inheritance, with early-onset in homozygotes and late-onset in heterozygotes of the gene.

A Statement of the World Veterinary Association (WVA) entitled “Policy Statement on Animal Welfare, Well-Being and Ethology” is introduced here with other policy or basic principles of some academic societies, universities and research institutes of several parts of the world. The members of the Japanese Society of Comparative Ophthalmology are primatologists, toxicologists, fish science researchers, zoo veterinarians, small and large animal practitioners, faculty members of veterinary or medical schools and others, so that the basic principles for animal welfare of the Editorial Board of the official magazine embrace a broad ophthalmologic field, practitional and basic, in mammals, birds, reptiles, fishes and so on, Furthermore, the Board of Regents of the Society supports the principles.

Therefore, we concur with the above policy statement of the WVA published in May of 1992 in Paris, France, in nearly all its articles.