24-Hour Contact Lens Sensor Monitoring of Intraocular Pressure-Related Profiles in Normal-Tension Glaucoma and Rates of Disease Progression

Abstract

Purpose: To determine the relationship between the rate of glaucomatous visual field loss and the amplitude of a 24-h intraocular pressure (IOP)-related profile measured using a contact lens sensor (CLS). Methods: This observational study included 22 patients with glaucoma and an IOP of consistently ≤21 mm Hg during office hours. All subjects underwent Goldmann tonometry, standard automated perimetry (SAP), dilated fundus examination, and had a CLS recording. A cosine function was used to obtain peak (acrophase), trough (bathyphase), and amplitude measurements. Prior rates of change in SAP mean deviation were calculated and compared to CLS parameters. Results: The patients had a mean (± SD) age of 66.6 ± 8.2 years (range 54-89 years). Mean follow-up was 6.6 ± 5.0 years with 8.3 ± 3.2 reliable SAP tests. The mean rate of change in SAP was -0.86 ± 1.0 dB per year (range -0.11 to -2.12 dB). Regression analysis suggested faster rates of prior visual field loss in eyes with higher-amplitude CLS curves, but this did not reach statistical significance (R² = 0.174, p = 0.053). The CLS accurately identified waking and sleeping periods.59.1% of eyes had a nocturnal acrophase (peaking between 23:00 and 07:00). There was no significant difference in rates of visual field change between patients with nocturnal or diurnal acrophase (-0.71 ± 1.17 and -1.07 ± 0.84 dB/year, respectively, p = 0.437). Conclusion: CLS recordings in patients with normal-tension glaucoma (defined by office hours IOP) indicated that 60% of patients had peak IOP during nocturnal hours, which may not be captured using conventional methods of IOP measurement. Novel parameters obtained using the CLS may provide information for predicting the risk of visual field changes for patients with glaucoma.

<p>Overnight Safety Evaluation of a Multi-Pressure Dial in Eyes with Glaucoma: Prospective, Open-Label, Randomized Study</p>

“…These results are compelling given the known risk of nocturnal, irregular IOP elevations and indicate the device could be worn nightly, similar to a continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea; notably, the design of the MPD would not preclude concomitant wear of a CPAP. 20 , 21 …”

Mean amplitude of intraocular pressure excursions: a new assessment parameter for 24-h pressure fluctuations in glaucoma patients

“…Also, the current clinically relevant definition of IOP fluctuation is confusing, non-uniform, and may not accurately reflect its role in glaucoma [9]. To study circadian IOP fluctuations, some researchers have investigated the use of contact lens sensors (CLSs), which measure IOP-related patterns continuously over 24 h [15,16]. However, CLSs are not available for most patients when compared with traditional 24-h IOP monitoring.…”

Outcome, influence factor and development of CLS measurement in continuous IOP monitoring: A narrative review

“…Later, Hoban et al implemented a retrospective study in a small population with normal-tension glaucoma. Based on the data directly provided by the manufacturer's software, this study only analyzed three variables, namely IOP amplitude, peak time, and trough time, and discovered that there was a tendency that a high IOP amplitude might lead to a faster visual field change rate, although there was no statistical difference [39].…”