Probability of global indices in low tension glaucoma

To know the pattern of visual field (VF) defect of low tension glaucoma (LTG), its diffuse and localized VF defects were compared using the significance values (p-value) of mean deviation (MD) and corrected pattern standard deviation (CPSD), which are calculated with STATPAC in Humphrey Visual Field Analyser. Sixteen eyes of LTG were enrolled and 34 eyes of primary open angle glaucoma (POAG) were used as controls. The degree of VF defects in LTG and POAG was relatively mild with the p-value of MD equal to or greater than 1%. Neither mean MD nor mean CPSD of LTG was significantly different from each of POAG (p > 0.8 and p > 0.2, respectively). Comparing the p-values of MD and CPSD, many patients showed more significant p-value of MD in LTG and POAG (62.5% and 61.8%, respectively). However, relatively more severe defect of CPSD tended to occur more frequently in LTG than in POAG (25% and 5.9%, respectively, chi 2 = 4.964, p < 0.09). The relation between p-values of MD and CPSD was not significantly influenced by the intraocular pressure, MD or vertical cup to disc ratio in either LTG or POAG.