Twenty-four-hour IOP measurements with a CLS showed that among IOP indicators studied, the range of IOP fluctuation was most important and significantly larger in NTG eyes compared with nonglaucoma eyes.
Purpose:We conducted the present study to determine (1) the best factor for distinguishing normal tension glaucoma (NTG) and nonglaucoma subjects based on the intraocular pressure (IOP) values measured by a CLS and (2) the optimal cutoff values of that factor.
Subjects and Methods:The eyes of 18 nonglaucoma subjects and 26 NTG patients were examined. We evaluated 5 indicators: maximum IOP value, SD, IOP fluctuation range, the cosine-fit curve amplitude, and the amplitude of dual-harmonic regression values. We determined the indicators' cutoff values to distinguish between nonglaucoma subjects and NTG patients with the area under the curve.
Results:The mean IOP values were 12.3 ± 2.7 mm Hg in the nonglaucoma eyes and 12.5 ± 3.1 mm Hg in the NTG eyes (P = 0.824). All 5 indicators were significantly higher in the NTG group. The best factor to distinguish the nonglaucoma subjects and NTG patients was the IOP fluctuation range (P < 0.0001, area under the curve = 0.844); the cutoff level value was 436.5 millivolt equivalents.Conclusions: Twenty-four-hour IOP measurements with a CLS showed that among IOP indicators studied, the range of IOP fluctuation was most important and significantly larger in NTG eyes compared with nonglaucoma eyes.