Porcine ophthalmology.

Although there appears to have been an increase in literature about the anatomy and physiology of the pig eye because of an expansion in its use as a model for research, there has been little written about the development of veterinary medicine in the area. Pig eyes share many similarities with human eyes, having a holangiotic retinal vasculature, no tapetum, cone photoreceptors in the outer retina, and a similar scleral thickness, rendering them valuable in comparative research. It must not be forgotten, however, that pigs are intelligent sentient animals which use vision as an important sense. Thus, diseases such as congenital cataracts, which impede vision, are important from the perspective of pig welfare. In addition, ocular lesions in this species, as with many others, can be a significant sign of systemic disease.