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 strenuous work and also may lack lean muscle. Horses with a very high body condition score carry too much weight, which interferes with stamina and biomechanics. Some studies addressed the relationship of body condition score and endurance performance in endurance races. In a study of the 1990 Purina Race of Champions (a 241-km / 150-mile, 2-day endurance race), it was found that the top-7 finishers of the race (i.e. highly competitive horses) had significantly lower body condition scores and marginally less rump fat than horses eliminated for metabolic criteria (i.e. less competitive horses). By contrast, two studies on the Tevis