The von Graefe test has been the standard dissociated phoria test for many years. The tangent scale dissociated phoria test commonly known as the modified Thorington test is gaining in popularity. This study compared distance and near phorias obtained with the von Graefe and modified Thorington procedures in 68 young adult subjects (mean age = 24.5 years). This study also compared the +/-1.00 gradient and calculated AC/A ratios obtained using von Graefe phorometry vs. modified Thorington testing. Distance phorias averaged very close to zero on both tests (0.1 Δ eso on the modified Thorington and 0.2 Δ exo on the von Graefe). Near phorias averaged 2.1Δ exo on the modified Thorington test and 3.7Δ exo on the von Graefe test. The von Graefe test showed more variability on both distance and near phorias and on AC/A ratios. The von Graefe test showed more relatively high phorias and more relatively high and low AC/A ratios than the modified Thorington test.