Glaucoma ducts, and narrowing or closure of the angle between the iris and cornea. The primary division in categorizing different types of glaucoma is open-angle and closed-angle (or angle-closure) glaucoma. In open angle glaucoma, the iris meets the cornea normally, allowing the fluid from inside the eye to drain, thus relieving the internal pressure. Where this angle is narrowed or closed, pressure increases over time, causing damage to the optic nerve, leading to blindness. Primary open-angle glaucoma (also, "primary glaucoma", "chronic glaucoma") refers to slow clogging of the drainage canals resulting in increased eye pressure which causes progressive optic nerve damage.
Henneke horse body condition scoring system before the race due to their high exercise levels, possibly also leading to a decrease in muscle mass. They explain the differences of results between the studies in part in that the participating horses of the 1990 Purina Race of Champions have had to qualify before and present a more highly-performing field of horses. Both Tevis Cup studies found that horses with a higher body condition score had, however, a significantly higher rate of not finishing the race due to lameness. Horses on pasture should enter the winter season at a body condition score of 6 or 7. On extremely