Twenty-six eyes from 26 patients with chiasmal compression, confirmed by neuroimaging, were recruited in the study from three sites (17 from Auckland City Hospital, Auckland, New Zealand; 8 from Cullen Eye Institute, Houston, TX; and 1 from Wills Eye Hospital, Philadelphia, PA). For each subject, the eye with the more reliable VF indices (fewest false positives, false negatives, and fixation losses) was included in the study (n = 26). All patients had magnetic resonance imaging (MRI) of the brain that confirmed a lesion compressing the optic chiasm with the following diagnoses: 20 pituitary adenomas, 2 craniopharyngioma, 2 suprasellar meningioma, 1 chiasmal pilocytic astrocytoma, and 1 hypothalamic astrocytoma. The research adhered to the tenets of the Declaration of Helsinki. The institutional review committees had approved the research and informed consent had been obtained.
All patients underwent a complete ophthalmic examination, including visual acuity, refraction, slit lamp biomicroscopy, gonioscopy, intraocular pressure (IOP) measurement with Goldmann tonometry, and dilated stereoscopic fundus examination. Patients were not excluded on the basis of their visual acuity, but all patients were required to be able to perform reliable VF testing. All patients had a spherical refractive error within the range of ± 5 D and IOP measurement of less than 21 mm Hg. Patients were excluded if they any had anterior segment, retinal, posterior segment, or optic nerve disease other than compressive optic neuropathy. Specifically, patients with known glaucoma, family history of glaucoma, or cup-to-disc ratio asymmetry of greater than 0.2, focal notching, or optic nerve hemorrhage were excluded. Patients were also excluded from the study if they had a history of diabetes or any other systemic illness that may affect the retina and optic nerve. All subjects were a minimum of 3 months after surgery, radiotherapy, or chemotherapy.