Nocturnal Variability of Intraocular Pressure Monitored With Contact Lens Sensor Is Associated With Visual Field Loss in Glaucoma

The impact of intraocular pressure fluctuations on the progression of glaucoma and associated factors

Background

In recent years, remarkable advancements in the comprehension of glaucoma pathophysiology have highlighted the necessity of looking beyond the conventional focus on mean intraocular pressure (IOP) levels. IOP fluctuations have been identified as a potential factor that could exert a substantial impact on the progression of glaucoma.

Main text

IOP exhibits dynamic variations throughout a 24-h cycle. Glaucoma patients exhibit substantially more pronounced IOP fluctuations compared to healthy individuals, even when the mean IOP remains within the normal range. This implies that IOP fluctuations may play a role in glaucoma progression through mechanisms independent of elevated mean IOP. In this review, an exhaustive examination of studies spanning the past decade was conducted to analyze the relationship between IOP fluctuations and disease progression in primary open-angle glaucoma (POAG), ocular hypertension (OHT), normal tension glaucoma (NTG), and primary angle-closure glaucoma (PACG). While a few studies present conflicting results, the majority of research supports the notion that elevated IOP fluctuations significantly contribute to disease progression in POAG patients. This association has also been confirmed in PACG patients. However, in NTG or OHT patients, other risk factors may outweigh IOP fluctuations in disease progression or glaucoma conversion. Additionally, we summarized common factors affecting IOP fluctuations to provide a basis for the identification of patients prone to significant daily IOP variations. Finally, the efficacy of various IOP-lowering interventions in modulating IOP fluctuations is concisely summarized, offering insights for the formulation of comprehensive treatment strategies that incorporate IOP fluctuation management.

Conclusions

IOP fluctuations play a significant role in disease progression in POAG and PACG. Individuals with certain systemic or ocular characteristics are more predisposed to pronounced and recurrent IOP fluctuations. Consequently, a comprehensive assessment of IOP fluctuation that transcends mean IOP values, as well as the integration of IOP fluctuations management into glaucoma treatment strategies are of paramount importance.

Negative Pressure Application by the Ocular Pressure Adjusting Pump to Lower Intraocular Pressure in Normal-Tension Glaucoma: HERCULES Study

PURPOSE

To evaluate the safety and intraocular pressure (IOP)-lowering efficacy of the ocular pressure adjusting pump in subjects with normal-tension glaucoma (NTG).

DESIGN

Prospective, multicenter, masked, randomized, fellow-eye controlled trial.

SUBJECTS, PARTICIPANTS, AND/OR CONTROLS

Subjects with NTG with an IOP ≥12 mm Hg and ≤21 mm Hg were enrolled. One eye of each subject was randomized to receive negative pressure application; the fellow eye served as a control.

METHODS

Subjects wore the device overnight for 1 year and the applied negative pressure was programmed by subtracting a reference IOP of 6 mm Hg from the baseline IOP.

MAIN OUTCOME MEASURES

The primary effectiveness endpoint was the proportion of eyes achieving an IOP reduction ≥20% at Week 52 during the day. The secondary endpoint was the proportion of eyes achieving a nocturnal IOP reduction ≥20% at Week 52. Exploratory endpoints included mean IOP reduction in clinic and in the sleep lab.

RESULTS

A total of 186 eyes were randomized across 11 sites. 120 eyes successfully completed all visits across 52 weeks without protocol deviations. At Week 52, 88.3% (n = 53) of study eyes vs 1.7% (n = 1) of control eyes met the primary endpoint. For the secondary endpoint, 96.7% (n = 58) of study eyes vs 5.0% (n = 3) met the endpoint. For exploratory IOP analysis, the mean nocturnal IOP reduction at Week 52 was 8.0 mm Hg (39.1%) from a baseline of 20.4 ± 2.5 mm Hg to 12.4 ± 2.7 mm Hg. There were no serious adverse events. The most commonly reported adverse events were lid (11.8% study, 1.1% control) and periorbital edema (12.9%, 1.1%).

CONCLUSIONS

The ocular pressure adjusting pump safely and effectively lowers both daytime and nocturnal IOP in patients with NTG.

The Benefit of Nocturnal IOP Reduction in Glaucoma, Including Normal Tension Glaucoma

Nocturnal intraocular pressure (IOP) profiling has shown that the peak IOP usually occurs at night, particularly in patients with glaucoma. Multiple studies have demonstrated that these nocturnal IOP elevations drive glaucomatous progression, often despite stable daytime IOP. Existing vascular dysregulation and decreased nighttime blood pressure compound the damage via low ocular perfusion pressure while elevated nocturnal IOP disrupts axonal transport. These findings are consistent with studies that indicate lowering nocturnal IOP is important for slowing glaucoma progression. Many of the current treatment options lower nighttime IOP significantly less than daytime IOP. Non-invasive IOP-lowering treatments that effectively lower nocturnal IOP remain an unmet need in the treatment of glaucoma.

The relationship between intraocular pressure and glaucoma: An evolving concept

Intraocular pressure (IOP) is the most important modifiable risk factor for glaucoma and fluctuates considerably within patients over short and long time periods. Our field's understanding of IOP has evolved considerably in recent years, driven by tonometric technologies with increasing accuracy, reproducibility, and temporal resolution that have refined our knowledge regarding the relationship between IOP and glaucoma risk and pathogenesis. The goal of this article is to review the published literature pertinent to the following points: 1) the factors that determine IOP in physiologic and pathologic states; 2) technologies for measuring IOP; 3) scientific and clinical rationale for measuring diverse IOP metrics in patients with glaucoma; 4) the impact and shortcomings of current standard-of-care IOP monitoring approaches; 5) recommendations for approaches to IOP monitoring that could improve patient outcomes; and 6) research questions that must be answered to improve our understanding of how IOP contributes to disease progression. Retrospective and prospective data, including that from landmark clinical trials, document greater IOP fluctuations in glaucomatous than healthy eyes, tendencies for maximal daily IOP to occur outside of office hours, and, in addition to mean and maximal IOP, an association between IOP fluctuation and glaucoma progression that is independent of mean in-office IOP. Ambulatory IOP monitoring, measuring IOP outside of office hours and at different times of day and night, provides clinicians with discrete data that could improve patient outcomes. Eye care clinicians treating glaucoma based on isolated in-office IOP measurements may make treatment decisions without fully capturing the entire IOP profile of an individual. Data linking home blood pressure monitors and home glucose sensors to dramatically improved outcomes for patients with systemic hypertension and diabetes and will be reviewed as they pertain to the question of whether ambulatory tonometry is positioned to do the same for glaucoma management. Prospective randomized controlled studies are warranted to determine whether remote tonometry-based glaucoma management might reduce vision loss and improve patient outcomes.

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

Glaucoma, marked by its intricate association with intraocular pressure (IOP), stands as a predominant cause of non-reversible vision loss. In this review, the physiological relevance of IOP is detailed, alongside its potential pathological consequences. The review further delves into innovative engineering solutions for IOP monitoring, highlighting the latest advancements in wearable and implantable sensors and their potential in enhancing glaucoma management. These technological innovations are interwoven with clinical practice, underscoring their real-world applications, patient-centered strategies, and the prospects for future development in IOP control. By synthesizing theoretical concepts, technological innovations, and practical clinical insights, this review contributes a cohesive and comprehensive perspective on the IOP biosensor's role in glaucoma, serving as a reference for ophthalmological researchers, clinicians, and professionals.

Morning Blood Pressure Surge and Glaucomatous Visual Field Progression in Normal-Tension Glaucoma Patients With Systemic Hypertension

PURPOSE

To investigate the impact of a morning blood pressure surge (MBPS) at baseline on subsequent visual field (VF) progression in hypertensive, normal-tension glaucoma (NTG) patients receiving oral anti-hypertensive treatment.

DESIGN

Retrospective cohort study.

METHODS

A total of 127 eyes from 127 newly diagnosed NTG patients treated for systemic hypertension and followed up for at least 2 years were analyzed. All patients underwent baseline 24-hour ambulatory blood pressure monitoring (ABPM) and at least 5 serial VF examinations during the follow-up period. VF progression was defined according to the Early Manifest Glaucoma Trial criteria. The associations of VF progression with 24-hour ABPM-based blood pressure (BP) parameters (including MBPS) and other clinical variables were analyzed using Cox regression analyses. Kaplan-Meier survival analysis was used to compare VF survival estimates in patients with and without MBPS.

RESULTS

VF progression was detected in 38 eyes (29.9%) over a 5.2-year mean follow-up. In the multivariate Cox regression model, a greater MBPS (hazard ratio [HR] = 1.033; P = .024) and lower nighttime mean arterial pressure (MAP) trough (HR = 0.965; P = .031) at baseline were significant independent predictors of subsequent VF progression. The likelihood of VF progression was significantly greater in patients with higher MBPS (P = .021) at baseline according to Kaplan-Meier survival analysis.

CONCLUSIONS

An increased MBPS at baseline is a significant independent predictor of subsequent VF progression in NTG patients with systemic hypertension. This may be another relevant BP parameter associated with VF progression in hypertensive NTG patients receiving oral anti-hypertensive treatment.

Negative Pressure Application via a Multi-Pressure Dial to Lower IOP in Patients with Suspected Glaucoma or Open Angle Glaucoma

PRCIS

The multi-pressure dial applies localized periocular negative pressure to safely and effectively lower IOP and represents the first non-invasive, non-pharmacologic device for IOP reduction.

OBJECTIVE

To evaluate the safety and effectiveness of the Multi-Pressure Dial (MPD) system, a device that applies periocular negative pressure to lower intraocular pressure (IOP).

SETTING

6 investigational sites, United States.

DESIGN

Prospective, assessor-masked, randomized controlled trial.

METHODS

Subjects with suspected glaucoma, ocular hypertension (OHTN), and open angle glaucoma (OAG) with baseline IOP ≥13 mmHg and ≤32 mmHg were enrolled. One eye of each subject was randomized to receive negative pressure application; the fellow eye served as a control. The study eye negative pressure setting was programmed for 60% of the baseline IOP. The primary effectiveness endpoint was the proportion of study eyes versus control eyes achieving an IOP reduction ≥20% at Day 90. Secondary endpoints included the proportion of eyes achieving an IOP reduction ≥25% at Day 90 as well as the proportion of eyes achieving an IOP reduction ≥20% at Days 30 and 60.

RESULTS

116 eyes of 58 subjects completed the study. At the Day 90 visit, 89.7% ( n =52) of study eyes versus 3.4% ( n =2) of control eyes achieved an IOP reduction ≥20% ( P <0.001). At Day 90, 77.6% ( n =45) of study eyes achieved a ≥25% IOP reduction compared to 1.7% ( n =1) of control eyes ( P <0.001). The most commonly reported adverse events were lid (17.2% study eye, 7.8% control eye) and periorbital edema (14.1% study eye, 10.9% control eye).

CONCLUSIONS

This trial demonstrates that the MPD safely and effectively lowers IOP in a group of patients that included glaucoma suspects, OHTN, and patients with OAG.

[The effect of body position on the results of central and paracentral rebound tonometry]

PURPOSE

This study analyzes the fluctuations of intraocular pressure (IOP) and clarifies the error of paracentral rebound tonometry associated with change in body position.

MATERIAL AND METHODS

The study included 45 healthy volunteers aged 25.4±2.1 years. First we performed rebound tonometry in the sitting position in the center of the cornea and 3-4 mm from the temporal and nasal sides (Icare-c, Icare-n, Icare-t, respectively) and bidirectional applanation tonometry (IOPcc - corneal compensated, IOPg - Goldmann tonometry). Then we measured Icare-c, Icare-n, Icare-t in the supine position, and after 5 minutes repeated Icare-c in the supine position. After this, we measured Icare-c, IOPcc and IOPg in the sitting position.

RESULTS AND DISCUSSION

Initial IOPcc and IOPg were 4.6±2.8 and 14.8±2.8 mm Hg. Initial Icare-c, Icare-t, and Icare-n measurements amounted to 15.0±1.9, 15.7±1.5 and 16.3±1.3 mm Hg; in the supine position the measurements were 16.4±2.1, 17.2±1.7 and 17.1±1.9 mm Hg. Paracentral measurements differed from Icare-c in both sitting and supine positions; only between Icare-t and Icare-n measured in the supine position there were no significant differences. The results of Icare-c, Icare-t, and Icare-n in body position change were comparable. Icare-c measured after 5 minutes in the supine position increased up to 16.6±2.4 mm Hg. Final IOPcc and IOPg did not differ from the initial measurements. Final Icare-c was lower than the initial result by 0.8±0.2 mm Hg, and lower than both supine Icare-c measurements by 2.1±0.2 and 2.6±0.2 mm Hg.

CONCLUSION

Paracentral rebound tonometry findings exceed those of rebound tonometry in central cornea, but in body position change the alteration of measurements in the same points on the cornea are comparable. In the supine position IOP increases on average by 1.0-1.5 mm Hg compared to the sitting position.

Using 24-h intraocular pressure-related patterns to identify open-angle glaucoma in thyroid eye disease

PURPOSE

Our study aims to develop a diagnostic model using 24-h intraocular pressure (IOP) patterns to differentiate between open-angle glaucoma (OAG) and dysthyroid optic neuropathy (DON) in thyroid eye disease (TED) patients with glaucoma-like symptoms.

METHODS

TED patients with elevated IOP, abnormal optic disc, and/or visual fields were prospectively recruited. The subjects whose symptoms were relieved by DON first-line treatments were divided into the DON group, and the subjects with previous diagnosis of OAG before TED onset were divided into the OAG group. The 24-h IOP was monitored by Tono-Pen in a sitting position during awake time and in a supine position during sleep time. All subjects were divided into a training set and a testing set. The diagnostic models were generated from training set by using either IOP curve-derived parameters or principal component (PC) factors. The discrimination ability was tested in training set based on area under curve (AUC), and the calibration ability was verified in testing set by Hosmer-Lemeshow goodness-of-fit. The sensitivity and specificity were calculated by two-by-two table with the cutoff value determined by Youden's index.

RESULTS

Thirty-two cases were recruited in each group. The 24-h IOP curves revealed a nocturnal pattern in both groups, with the acrophase moving slightly forward in the DON group (21:00 pm-24:00 pm) compared to the OAG group (22:00 pm-3:00 am). Several IOP curve-derived parameters differed between the two groups, with larger amplitude during sleep time (P < 0.000) and longer duration of IOP ≥ 21 mmHg at awake time (P = 0.004) in the DON group than the OAG group. However, the diagnostic model generated from IOP parameters showed poor reliability (P = 0.001) in calibration test and was rejected. The other model built on PC factors achieved good performance of discrimination (AUC = 0.943) and calibration (P = 0.139) with a sensitivity of 87.50% and a specificity of 95.83% at cutoff value of 0.538 to identify OAG cases.

CONCLUSION

The diagnostic model facilitates discrimination between OAG and DON in TED patients based on 24-h IOP-related patterns.

TRIAL REGISTRATION

This work was registered on Chinese Clinical Trial Registry (ChiCTR1900025394).

HIOP-Reader: Automated Data Extraction for the Analysis of Manually Recorded Nycthemeral IOPs and Glaucoma Progression

Purpose

Nycthemeral (24-hour) intraocular pressure (IOP) monitoring in glaucoma has been used in Europe for more than 100 years to detect peaks missed during regular office hours. Data supporting this practice are lacking, because it is difficult to correlate manually drawn IOP curves to objective glaucoma progression. To address this, we developed an automated IOP data extraction tool, HIOP-Reader.

Methods

Machine learning image analysis software extracted IOP data from hand-drawn, nycthemeral IOP curves of 225 retrospectively identified patients with glaucoma. The relationship between demographic parameters, IOP, and mean ocular perfusion pressure (MOPP) data to spectral-domain optical coherence tomography (SDOCT) data was analyzed. Sensitivities and specificities for the historical cutoff values of 15 mm Hg and 22 mm Hg in detecting glaucoma progression were calculated.

Results

Machine data extraction was 119 times faster than manual data extraction. The IOP average was 15.2 ± 4.0 mm Hg, nycthemeral IOP variation was 6.9 ± 4.2 mm Hg, and MOPP was 59.1 ± 8.9 mm Hg. Peak IOP occurred at 10 am and trough at 9 pm. Progression occurred mainly in the temporal-superior and temporal-inferior SDOCT sectors. No correlation could be established between demographic, IOP, or MOPP variables and disease progression on OCT. The sensitivity and specificity of both cutoff points (15 and 22 mm Hg) were insufficient to be clinically useful. Outpatient IOPs were noninferior to nycthemeral IOPs.

Conclusions

IOP data obtained during a single visit make for a poor diagnostic tool, no matter whether obtained using nycthemeral measurements or during outpatient hours.

Translational Relevance

HIOP-Reader rapidly extracts manually recorded IOP data to allow critical analysis of existing databases.