Normal tension glaucoma about four times as high as the prevalence of the "classical glaucoma" with an IOP of 22 mm Hg and higher. The pillar of the current understanding of normal tension glaucoma is a reduced IOP tolerance of the retinal ganglion cells and the cells in the optic nerve head - an IOP of, for example, 17 or 19 mm Hg that would not affect a healthy eye leads to damage in the eye of an NTG patient. In many patients, normal tension glaucoma is common in individuals with a generalized reduced perfusion of organs and certain body tissues. A low
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