Purpose: This study was performed to determine the prevalence of acquired pits of the optic nerve (APON) in glaucoma and the characteristics of associated visual field loss.
Subjects and methods: Stereoscopic optic disc photos from 235 patients with a low-tension variety of primary open-angle glaucoma (LTG) and 251 primary open-angle glaucoma patients with intraocular pressures higher than 21 mmHg (HTG) were examined for the presence of typical APON as defined by a standard photograph (Fig 1). Associated visual field loss was evaluated with automated perimetry and patterns of field loss were identified.
Results: Out of a total of 486 patients, 63 APON were found in 51 eyes of 44 glaucoma patients. APONs were more prevalent in women. Acquired pits were more frequently (p<0.001) located inferiorly (70%) than superiorly (30%). There was a significantly higher prevalence (p<0.001) of APON in LTG patients (12.7%) than in HTG patients (5.6%). Dense visual field defects within five degrees of fixation occurred in 96% of patients with APON.
Conclusion: Acquired pits of the optic nerve are more often located at the inferior optic disc than at the superior disc and are nearly always associated with visual field loss close to fixation. In a glaucoma referral center setting, APON are more prevalent in lower pressure glaucoma than in higher pressure glaucoma.