Oval corneal opacities in beagles. III. Histochemical demonstration of stromal lipids without hyperlipidemia.

We found oral stromal avascular corneal opacities in 128 eyes of 75 beagles from 497 studied. There were three morphologic types that progressed in severity with time; nebular, racetrack, and white arc. Histochemical study of the earliest morphologic type (nebular) revealed neutral fats, cholesterol, phospholipids, and sometimes fatty acids both intracellularly and extracellularly. We found no elevation of serum cholesterol or triglycerides except in dogs with the most advanced morphologic type (white arc) and no alteration in thyrometabolic function. We think that oval stromal opacities in beagle corneas are a primary disorder of corneal lipid metabolism closely resembling the central crystalline dystrophy of Schnyder and may be an animal model for this human disease.