Twenty-Four-Hour Intraocular Pressure Indicators Distinguish Normal Tension Glaucoma From Healthy Eyes Measured With a Contact Lens Sensor.

Abstract

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. 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. 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. The mean IOP values were 12.3±2.7mmHg in the nonglaucoma eyes and 12.5±3.1mmHg 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. 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.