CORRELATION OF ASYMMETRY OF VISUAL-FIELD LOSS WITH OPTIC DISC TOPOGRAPHY IN NORMAL-TENSION GLAUCOMA

Objective: To compare the differences in optic disc configuration with different stages of visual field loss in normal-tension glaucoma. Des ign: Interocular pairwise comparisons. Setting: Glaucoma clinic of a t eaching hospital. Patients: Thirteen patients with normal-tension glau coma and asymmetric visual field loss of at least 2.5 dB in the mean d efect of the visual field indexes.Interventions: Areas under the optic disc profiles mapped from values for radial sections of the optic dis c measured at intervals of 30-degrees and expressed as percentages of the area of a rectangle were obtained from stereophotographs with a co mputerized image analysis system. Visual fields were tested with autom ated perimetry (OCTOPUS), using program G1. Main Outcome Measure: Corr elation analyses between the interocular differences in the areas unde r the optic disc profile and the interocular differences in the visual field indexes. Results: The correlation coefficients between the inte rocular differences in mean defect and those of the area under the opt ic disc profile in the superior to temporal sections ranged from -.71 to -.61 (.007<P<.028). The interocular differences in loss variance co rrelated with the differences in the area under the optic disc profile in the superior section (r=-.61, P=.0252). Conclusion: The difference s in visual field loss between the two eyes in normal-tension glaucoma appear mainly to reflect morphometric changes in the superior half of the optic disc.