An analysis of the refractions of patients with primary open angle glaucoma, ocular hypertension (OH), and low-tension glaucoma showed that myopia occurred more frequently in each group than would be expected in a normal population of similar age. One in three of the myopes with OH had glaucomatous field defects on follow-up examination, whereas the defects developed in only one in 20 of the emmetropes and in one in 40 of the hypermetropes. These results suggest that myopic eyes are more susceptible to the effects of raised intraocular pressure than are nonmyopic eyes and that myopes with OH have a particularly high risk of the development of field defects.