Anatomical attributes of the optic nerve head in eyes with parafoveal scotoma in normal tension glaucoma.

Abstract

PurposeTo evaluate optic nerve characteristics independent of systemic factors predisposing to parafoveal scotoma in normal tension glaucoma.MethodsWe included 40 patients with bilateral normal tension glaucoma with parafoveal scotoma (visual field defect in one hemifield within 10° of fixation with at least one point at pResultsThe PF group had lower mean deviation(MD) and visual field index (VFI) and higher pattern standard deviation (PSD) than control group (p≤0.001) for similar untreated IOP, (p = 0.9). Disc haemorrhages were more frequent in the PF group, p = 0.01. The PF group had greater width of nerve fibre layer defects, p = 0.05 and greater vertical displacement of the central vessel trunk, p = 0.001. On multivariate logistic regression, parafoveal scotoma was significantly associated with increased vertical distance of the CVT, p = 0.0001.ConclusionIncreased vertical displacement of the CVT is associated with parafoveal scotoma in normal tension glaucoma. Localising the vessel trunk may help clinicians in identifying patients at risk for parafoveal involvement.