Tonometry in glaucomatous globes.

The Mackay-Marg, pneumatonograph, and EMT-20 tonometers were evaluated in the eyes of glaucomatous beagles. Tonometric scale readings were compared to the manometric recordings from the anterior chamber. Tonometry was performed with manometric system closed and open to the reservoir column. The Mackay-Marg tonometer evaluated in the closed and open manometric systems was highly reliable (goodness of fit [r2] = 0.852 and 0.816, respectively) with intraocular pressures up to 50 mm Hg and somewhat lower (r2 = 0.818 and 0.740, respectively) with intraocular pressures up to 100 mm Hg. The pneumatonograph also exhibited high reliability (r2 = 0.892 [closed] and 0.806 [open]) at pressures up to 50 mm Hg and (r2 = 0.796 [closed] and 0.75 [open]) at pressures up to 100 mm Hg. The EMT-20 tonometer was the least satisfactory for the glaucomatous globe, with r2 ranging from 0.235 to 0.654.