A comparative study on visual field defect in low tension glaucoma

The mode of visual field defect and the change of intraocular pressure (IOP) were analyzed between progressive low tension glaucoma (LTG) and non-progressive LTG. Maximum IOP and phasic fluctuation in IOP during the follow-up period in progressive cases were significantly higher than those in non-progressive cases (p less than 0.01). This greater range in phasic fluctuation may lead to the development of glaucomatous damage. Analysis of the pattern of visual field defect revealed significantly greater frequency of dense defects within 10 degrees of the fixation area in progressive cases. Another analysis on the mode of visual field damage between progressive LTG and POAG demonstrated higher frequency of focal progression of the damage. These results suggest that there are some different etiological factors among progressive LTG, non-progressive LTG and POAG, while focal anatomical weakness at the optic nerve head also influences the development of damage in some case of progressive LTG.