The Relationship Between Optic Disc Area and Open-Angle Glaucoma

Purpose To determine if eyes with larger optic disc area are more likely to have open-angle glaucoma or to have glaucoma at lower intraocular pressure (IOP). Methods Data were collected from a population-based sample of adults residing in East Baltimore, consisting of demographic information, ocular examinations, automated and static/kinetic visual field tests, IOP as measured by applanation tonometry, and image analysis of the optic disc. Optic disc area was calculated using refractive error to correct magnification. Open-angle glaucoma was defined by visual field and optic disc criteria. One eye from each of 75 patients with glaucoma was compared to those of 3,518 subjects without glaucoma. Results Although optic disc area was somewhat larger among patients with glaucoma than control subjects, in a regression model adjusting for age, gender, and race, the significance of this difference had a probability of 0.06. Among patients with glaucoma, disc area was not related to IOP level measured at study examination. Conclusion Disc area is a weak risk factor for open-angle glaucoma. Disc area did not differ between patients with glaucoma who had lower IOP and those who had higher IOP among a group with glaucoma that were identified in a population survey.