From the American Academy of Ophthalmology

Researchers compared the amount of IOP asymmetry in a large group of ethnically diverse patients with and without glaucoma to determine the probability of having primary open-angle glaucoma at each level of IOP asymmetry. Patients with an IOP difference of ≥6mm Hg should be considered at great risk for having glaucoma, while those with symmetric pressures are not likely to have the disease. As a diagnostic consideration, the value of asymmetry should be weighted heavily in patients who show consistent IOP asymmetry on repeat clinic visits. Journal of Glaucoma, March 2012