Spontaneous intraocular pressure reduction ire normal-tension glaucoma andassociated clinical factors

Purpose: To investigate the intraocular pressure (IOP) reduction in certain normal-tension glaucoma (NTG) patients and clinical factors associated wit h this reduction. Methods: Fifty-four NTG patients who met the following enrollment criteria were selected: IOP <21 mm Hg during a 24-hour pressure curve and throughout the subsequent 12 months; examined every 1 to 4 months for at least 3 year s with no ocular hypotensive therapy. For each patient, the eye with the hi gher mean IOP during the 24-hour pressure curve was selected fur this study . Results: Six patients had an IOP reduction which was defined as a significa nt decrease (P < .05) of IOP over time, determined by the Spearman rank con -elation coefficient method. These 6 eyes were rated positive for subsequen t IOP reduction. The IOP reduction was correlated to clinical factors by me ans of a logistic multiple regression analysis (LOGIST procedure using PC-S AS), which demonstrated that the larger difference between the maximum IOP and the minimum IOP during the initial 24-hour pressure curve and the absen ce of disc hemorrhage showed significant correlation with IOP reduction (P = .026 and P = .013, respectively). The odds ratios were 2.05 per 1 mm Hg i ncrease of difference between the maximum IOP and the minimum IOP during th e initial 24-hour pressure curve and 1.13 for the absence of disc hemorrhag e. Conclusions: The current study demonstrated that a significant reduction of IOP over time is not uncommon in NTG patients. One ninth of the NTG patien ts in this study showed a significant IOP reduction during a 3-year follow- up period. Jpn J Ophthalmol 2000;44:263-267 (C) 2000 Japanese Ophthalmologi cal Society.