Forty consecutive patients with chiasmal compression syndromes were prospectively recruited from the Neuro-ophthalmology and Neurosurgery Departments of the University of Auckland, New Zealand, and the Wills Eye Institute, Philadelphia, Pennsylvania. 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. Exclusion criteria comprised unreliable VF testing (>33% false positives, or false negatives, or fixation losses), any anterior segment, retinal, posterior segment, or optic nerve disease other than compressive optic neuropathy, including known glaucoma, cup-to-disc ratio asymmetry of greater than 0.2, focal notching, or optic nerve hemorrhage. In each patient, the presence of a chiasmal lesion was confirmed by magnetic resonance imaging (MRI). Patients were excluded from the study if they had undergone any previous radiotherapy or medical treatment. In the preoperative assessment, all patients underwent testing of VA, refraction, slit lamp biomicroscopy, applanation intraocular pressure measurement, stereoscopic fundus evaluation, VF testing with a perimeter (Humphrey Visual Field Analyzer 2 [HFA2], 24-2 program, SITA Standard; Carl Zeiss Meditec, Dublin, CA), and OCT Fast RNFL scan. After surgery, repeated measurements of VA, color vision testing with Ishihara plates, intraocular pressure measurement, slit lamp biomicroscopy, fundus examination, OCT RNFL measurement, and VF testing were undertaken. Preoperative assessments were performed up to 2 months before surgery, and postoperative visits occurred up to 6 weeks after surgery.
Five patients did not meet the entrance criteria to the study, four due to inability to undergo VF testing, either before or after surgery, and one because of not meeting the study’s time frames for the preoperative assessment. Of the remaining 70 eyes (of 35 patients), 7 were excluded from this analysis due to unreliable VFs at either the pre- or postoperative assessment.