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. 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.

Pharmaceutical Approaches to Normal Tension Glaucoma

“…Supporting this theory, NTG patients have shown a larger circadian IOP fluctuation as compared to normal subjects [ 33 ]. Studies have demonstrated that, although within the statistically normal range, the IOP mean value, range and amplitude and frequency of nocturnal IOP spikes in the supine position are significant risk factors for glaucoma progression in NTG patients [ 34 , 35 ].…”

Advancements in Wearable and Implantable Intraocular Pressure Biosensors for Ophthalmology: A Comprehensive Review

“…Accuracy data for IOP biosensors are summarized in Figure 10. On the supply side, recent innovations in both CLS [114,[145][146][147][148][149][150][151] and hydrogel contact lens technology [96,152,153] have enabled advanced biosensors to engage in accurate, safe, and clinically actionable 24 h monitoring of IOP in both normal and glaucomatous eyes. With respect to the fungibility of CLS data with GAT measurements, Szurman and colleagues [133] measured a mean difference in IOP of −0.2 mmHg between patients using an implantable CLS and those subject to GAT measurement, which the authors categorized as "excellent" and in excess of the instrumental agreement between non-biosensorbased IOP measurement modalities such as GAT as compared to rebound tonometry.…”

“…Given that elevated IOP is simultaneously the main driver of glaucoma and the central therapeutic target in clinical practice, wearable and implantable IOP biosensors are patently useful in glaucoma management [160]. The vast majority of studies using IOP biosensors are conducted upon patients with primary open-angle glaucoma (POAG) [124,143,148,151,[161][162][163][164] and normal tension glaucoma (NTG) [143,148,151,162].…”