Large diurnal fluctuations in intraocular pressure are an independent risk factor in patients with glaucoma

Agreement of Serial iCare HOME2 and Goldmann Applanation Tonometry

PURPOSE

To assess agreement of iCare HOME2 and Goldmann applanation tonometry over a wide range of IOP.

DESIGN

A prospective, observational cohort study.

SUBJECTS

Twenty-six adult patients undergoing intravitreal injection, which temporarily raises IOP, were recruited from the Palo Alto Medical Foundation Retina Clinic between October 2022 and February 2023.

METHODS

Subjects had serial iCare HOME2 (IOPI) and Goldmann applanation (IOPG) IOP measurements before and at 0 and 5-10 minutes after injection. Baseline IOPs and pachymetry were taken in both eyes.

MAIN OUTCOME MEASURES

Correlation between IOPI and IOPG was tested by within-subjects Intraclass Correlation Coefficient (ICC) for repeated measures. Agreement between IOPI and IOPG was evaluated by a Bland-Altman plot with correction for multiple measurements. The difference between IOPI and IOPG was evaluated between eyes at baseline (Pearson's r) and within the injected eye over different timepoint (ICC for absolute agreement). Linear regression was used to evaluate the effect of age, sex, glaucoma, and corneal thickness.

RESULTS

The mean IOPI and IOPG were 25.3 (range: 9 - 55) and 23.5 (range: 8 - 56) mmHg, respectively. Correlation between IOPI and IOPG was 0.99 (p<0.001). The mean difference (IOPG - IOPI) was 2.2 mmHg (95% limits of agreement: -3.4 to 7.8 mmHg). The bias in measurements was correlated between eyes (r: 0.68, p<0.001) and in the injected eye across all timepoints (ICC: 0.86, 95% CI: 0.75 to 0.93), but did not show a relationship with age, sex, glaucoma or corneal thickness.

CONCLUSION

IOPI and IOPG showed excellent correlation, however there was a stable bias toward IOPG being higher than IOPI over a large range of IOP.

Association of Long-Term Intraocular Pressure Variability and Rate of Ganglion Complex Thinning in Patients With Glaucoma

PURPOSE

To evaluate the association of mean intraocular pressure (IOP) and IOP variability (IOP fluctuation [SD of IOP] and the IOP range) with the rate of ganglion cell complex (GCC) layer thinning over time in patients with glaucoma.

DESIGN

Prospective cohort study.

METHODS

Participants with at least 4 visits and 2 years of follow-up of optical coherence tomography tests were included. A linear mixed-effect model was used to investigate the association of IOP parameters with the rates of GCC thinning. Subgroup analyses were conducted for eyes with early (MD ≥ -6 dB), and moderate to advanced stage (MD < -6 dB) at baseline.

RESULTS

The cohort consisted of 369 eyes of 249 glaucoma patients (282 early glaucoma and 87 moderate to advanced glaucoma) with mean (standard deviation [SD]) age of 68.2 (10.7) years over 5.1 years of follow-up. The mean rate of GCC change was -0.59 (95% confidence interval [CI], -0.67 to -0.52) µm per year. In multivariable models, faster annual rate of GCC thinning was associated with a higher IOP fluctuation (-0.17 [95% CI, -0.23 to -0.11] µm per 1-mmHg higher, P < .001) or higher IOP range (-0.07 [95% CI, -0.09 to -0.05] µm per 1-mmHg higher, P < .001) after adjustment for mean IOP and other confounding factors. Similar results were found for early and moderate to advanced stages of glaucoma.

CONCLUSIONS

IOP variability showed an independent association with macular change in patients with glaucoma regardless of severity at baseline, even after adjustment for mean IOP, supporting its potential value as a therapeutic target for clinical decision-making.

A Randomized, Controlled Comparison of NCX 470, a Nitric Oxide-Donating Bimatoprost, and Latanoprost in Subjects with Open-Angle Glaucoma or Ocular Hypertension: The MONT BLANC Study

PURPOSE

To compare intraocular pressure (IOP)-lowering efficacy and safety of NCX 470, a nitric oxide (NO)-donating bimatoprost, to latanoprost in subjects with open-angle glaucoma (OAG) or ocular hypertension (OHT).

DESIGN

Prospective, phase 3, randomized, adaptive dose-selection, double-masked, parallel-group trial.

METHODS

691 subjects with OAG or OHT and unmedicated IOP ≥26 mmHg at 8AM, ≥24 mmHg at 10AM, and ≥22 mmHg at 4PM in the study eye were randomized to NCX 470 0.065%, NCX 470 0.1%, or latanoprost 0.005%. An interim analysis was performed to select the final dose of NCX 470. We evaluated noninferiority of NCX 470 versus latanoprost, based on IOP reduction from baseline at 8AM and 4PM at 2 weeks, 6 weeks, and 3 months.

RESULTS

661 subjects were analyzed; IOP was significantly reduced at all on-treatment time points, with reductions ranging from 8.0 to 9.7 mmHg (P < .0001 at each time point) in the NCX 470 0.1% group. Mean IOP reductions were greater with NCX 470 0.1% than latanoprost 0.005% at all 6 time points and significantly greater (P < .05) at 4 of the 6 time points. The most common adverse event was conjunctival/ocular hyperemia.

CONCLUSION

The NO-donating prostaglandin analogue NCX 470 0.1% was well-tolerated and lowered IOP more than latanoprost in subjects with OAG or OHT at all 6 time points. With a dual mechanism of action that enhances both uveoscleral and trabecular outflow, NCX 470 could become an important first-line therapy for IOP reduction in glaucoma.

Appropriate patient population for future visual system axon regeneration therapies

A number of blinding diseases caused by damage to the optic nerve result in progressive vision loss or loss of visual acuity. Secondary glaucoma results from traumatic injuries, pseudoexfoliation or pigmentary dispersion syndrome. Progressive peripheral vision loss is common to all secondary glaucoma irrespective of the initial event. Axon regeneration is a potential therapeutic avenue to restore lost vision in these patients. In contrast to the usual approach of having the worst possible patient population for initial therapies, axon regeneration may require consideration of appropriate patient population even for initial treatment trials. The current state of axon regeneration therapies, their potential future and suitable patient population when ready is discussed in this perspective. The selection of patients are important for adoption of axon regeneration specifically in the areas of central nervous system regenerative medicine. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology Neurological Diseases > Biomedical Engineering Metabolic Diseases > Molecular and Cellular Physiology.

In vivo assessment of the ocular biomechanical properties in patients with idiopathic normal pressure hydrocephalus

PURPOSE

Idiopathic normal pressure hydrocephalus (iNPH) is associated with an increased prevalence of open-angle glaucoma, attributed to variations of the pressure gradient between intraocular and intracranial compartments at the level of the lamina cribrosa (LC). As ocular biomechanics influence the behavior of the LC, and a lower corneal hysteresis (CH) has been associated to a higher risk of glaucomatous optic nerve damage, in this study we compared ocular biomechanics of iNPH patients with healthy subjects.

METHODS

 Twenty-four eyes of 24 non-shunted iNPH patients were prospectively recruited. Ocular biomechanical properties were investigated using the ocular response analyzer (Reichert Instruments) for the calculation of the CH, corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc). Results were compared with those of 25 eyes of 25 healthy subjects.

RESULTS

 In iNPH eyes, the median CH value and interquartile range (IQR) were 9.7 mmHg (7.8-10) and 10.6 mmHg (9.3-11.3) in healthy controls (p = 0.015). No significant differences were found in IOPcc [18.1 mmHg (14.72-19.92) vs. 16.4 mmHg (13.05-19.6)], IOPg [15.4 mmHg (12.82-19.7) vs. 15.3 mmHg (12.55-17.35)], and CRF [9.65 mmHg (8.07-11.65) vs. 10.3 mmHg (9.3-11.5)] between iNPH patients and controls.

CONCLUSIONS

 In iNPH patients, the CH was significantly lower compared to healthy subjects. This result suggests that ocular biomechanical properties may potentially contribute to the risk of development of glaucomatous optic nerve damage in iNPH patients.

Posture-related fluctuations of intraocular pressure in healthy children with suspicion of glaucoma

PURPOSE

Currently, there are no specific data on the circadian course of intraocular pressure (IOP) in children, especially for IOP measurements in the supine position. The study aimed to characterize the diurnal and nocturnal IOP fluctuations in supine and sitting positions in patients less than 18 years of age.

METHODS

Seventy-nine eyes of 79 patients under 18 years of age with suspicious optic nerve heads or ocular hypertension could be included in this study. All included patients showed an inconspicuous retinal nerve fiber layer thickness and Bruch's membrane minimum rim width by coherence tomography. IOP measurements during the 24-h IOP profile were retrospectively evaluated. Measurements were taken at 10:00, 16:00, 20:00, and 23:00 h in the sitting position and at 6:00 h in the morning in the supine position using iCare rebound tonometry on 2 consecutive days.

RESULTS

Thirty-four of 79 children (43.0%) had peak nocturnal IOP values > 25 mmHg. The mean daily IOP was 18.8 ± 5.6 mmHg, and the mean daily fluctuation was 6.1 ± 4.0 mmHg. At 6 am, supine measurements were elevated to 25.1 ± 8.0 mmHg. Extensive fluctuations with values > 40 mmHg in the nocturnal supine measurement occurred in a relevant share of patients (n = 5).

CONCLUSION

There appear to be relevant diurnal and nocturnal IOP fluctuations in healthy children (< 18 years). Nocturnal IOP measurements in supine patients with risk factors for glaucoma may provide important additional information to identify critical patients for further follow-up.

Efficacy and Safety of the Travoprost Intraocular Implant in Reducing Topical IOP-Lowering Medication Burden in Patients with Open-Angle Glaucoma or Ocular Hypertension

PURPOSE

A randomized, double-masked, multicenter, phase 2 trial to evaluate the long-term safety and efficacy of travoprost intraocular implant, an extended-release drug delivery system designed to provide uninterrupted sustained intraocular pressure (IOP)-lowering therapy, thereby reducing patient treatment burden and improving adherence with IOP-lowering medication.

METHODS

Patients with open-angle glaucoma or ocular hypertension were administered a fast-eluting implant (FE implant, n = 51) and received twice-daily (BID) placebo eye drops, a slow-eluting (SE implant, n = 54) and received BID placebo eye drops, or underwent a sham surgical procedure and received BID timolol 0.5% (n = 49). IOP was measured at baseline, day 1-2, day 10, week 4, week 6, month 3, and every 3 months thereafter through 36 months. Efficacy was evaluated by mean change from 8:00 AM unmedicated baseline IOP through month 36, and the percentage of patients receiving the same or fewer topical IOP-lowering medications as at screening (pre-study). Safety was evaluated by adverse events and ophthalmic parameters.

RESULTS

Clinically and statistically relevant IOP-lowering treatment effects were observed through month 36 after a single administration of the travoprost implant compared with BID timolol with mean IOP reductions ranging from 7.6 to 8.8 mmHg for the FE implant group, from 7.3 to 8.0 mmHg for the SE implant group, and from 7.3 to 7.9 for the timolol group at the 8:00 AM timepoint (P < 0.0001 for all treatment groups at all visits). At months 12, 24, and 36, a greater percentage of FE and SE implant patients versus timolol patients were well controlled on the same or fewer topical IOP-lowering medications compared with screening with 63 and 69% for the FE and SE implants groups, respectively, versus 45% for the timolol group at month 36. The safety profile of the implant was favorable; there were no dislodgements, no explantations, no adverse events of conjunctival hyperemia or periorbital fat atrophy, no discontinuations due to study eye adverse events, nor any serious adverse events in the study eye. Comparable changes from baseline in corneal endothelial cell counts were observed in the three treatment groups over the 36 months.

CONCLUSION

The travoprost intraocular implant demonstrated robust IOP-lowering and substantially reduced topical IOP-lowering medication burden for up to 36 months following a single administration, while maintaining a favorable safety profile. The travoprost intraocular implant promises to be a meaningful addition to the interventional glaucoma armamentarium by addressing the key shortcomings of topical IOP-lowering medications, including low adherence and topical side effects while controlling IOP for up to 36 months.

TRIAL REGISTRY

ClinicalTrials.gov identifier NCT02754596 registered 28 April 2016.

Effect of Different Postures on Intraocular Pressure in Open-Angle Glaucoma

INTRODUCTION

This study aims to investigate the pattern of intraocular pressure (IOP) changes in different postures among patients with open-angle glaucoma (OAG).

METHODS

A observational study was conducted on a total of 74 patients with OAG (148 eyes). IOP measurements were taken in a variety of positions, including supine, left lateral decubitus, right lateral decubitus, head tilted downwards position with immediate head-up (transient head tilted downwards), seated, seated with head tilted downwards, standing, and walking. Each position was held for 5 min before measurement. In all positions, the patient maintains both eyes looking forward and remains alert. In the head tilted downwards position, the angle of head tilt with respect to the sagittal plane was 30°.

RESULTS

The overall trend of IOP changes showed a significant decrease with an increase in the position height (r = 0.037, p < 0.001). The IOP was significantly higher in the supine, left lateral decubitus, right lateral decubitus, and head tilted downwards positions than in the seated position (p < 0.001). Compared with the seated position with eyes at primary gaze, IOP decreased significantly when standing (p = 0.008) or walking (p < 0.001). The IOP in the left lateral decubitus and right lateral decubitus was significantly higher than in the supine position (p = 0.008, p = 0.001, respectively). The IOP decreased significantly during walking compared with standing (p < 0.001).

CONCLUSIONS

The magnitude of IOP strongly correlates with the body position during IOP measurement. The head tilted downwards, supine, left lateral decubitus, and right lateral decubitus positions result in a higher IOP than IOP at the seated position. Patients with OAG can potentially reduce IOP fluctuations by adjusting their daily postures.

Secondary glaucoma: Toward interventions based on molecular underpinnings

Glaucoma is a heterogeneous group of progressive diseases that leads to irreversible blindness. Secondary glaucoma refers to glaucoma caused by a known underlying condition. Pseudoexfoliation and pigment dispersion syndromes are common causes of secondary glaucoma. Their respective deposits may obstruct the trabecular meshwork, leading to aqueous humor outflow resistance, ocular hypertension, and optic neuropathy. There are no disease-specific interventions available for either. Pseudoexfoliation syndrome is characterized by fibrillar deposits (pseudoexfoliative material) on anterior segment structures. Over a decade of multiomics analyses taken together with the current knowledge on pseudoexfoliative glaucoma warrant a re-think of mechanistic possibilities. We propose that the presence of nucleation centers (e.g., vitamin D binding protein), crosslinking enzymes (e.g., transglutaminase 2), aberrant extracellular matrix, flawed endocytosis, and abnormal aqueous-blood barrier contribute to the formation of proteolytically resistant pseudoexfoliative material. Pigment dispersion syndrome is characterized by abnormal iridolenticular contact that disrupts iris pigment epithelium and liberates melanin granules. Iris melanogenesis is aberrant in this condition. Cytotoxic melanogenesis intermediates leak out of melanosomes and cause iris melanocyte and pigment epithelium cell death. Targeting melanogenesis can likely decrease the risk of pigmentary glaucoma. Skin and melanoma research provides insights into potential therapeutics. We propose that specific prostanoid agonists and fenofibrates may reduce melanogenesis by inhibiting cholesterol internalization and de novo synthesis. Additionally, melatonin is a potent melanogenesis suppressor, antioxidant, and hypotensive agent, rendering it a valuable agent for pigmentary glaucoma. In pseudoexfoliative glaucoma, where environmental insults drive pseudoexfoliative material formation, melatonin's antioxidant and hypotensive properties may offer adjunct therapeutic benefits. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology.

Alternatives to Topical Glaucoma Medication for Glaucoma Management

Topical glaucoma medications have favorable safety and efficacy, but their use is limited by factors such as side effects, nonadherence, costs, ocular surface disease, intraocular pressure fluctuations, diminished quality of life, and the inherent difficulty of penetrating the corneal surface. Although traditionally these limitations have been accepted as an inevitable part of glaucoma treatment, a rapidly-evolving arena of minimally invasive surgical and laser interventions has initiated the beginnings of a reevaluation of the glaucoma treatment paradigm. This reevaluation encompasses an overall shift away from the reactive, topical-medication-first default and a shift toward earlier intervention with laser or surgical therapies such as selective laser trabeculoplasty, sustained-release drug delivery, and micro-invasive glaucoma surgery. Aside from favorable safety, these interventions may have clinically important attributes such as consistent IOP control, cost-effectiveness, independence from patient adherence, prevention of disease progression, and improved quality of life.

Twenty-Four-Hour Intraocular Pressure Pattern In Glaucoma Suspects in an African Population

PRCIS

Twenty-four-hour intraocular pressure measurement (Phasing) among glaucoma suspects showed higher intraocular pressure (IOP), greater fluctuation, and more varying peak times occurring mostly outside clinic hours, between 12 midnight and 8 am in 68.9% of them.

PURPOSE

To characterise 24-hour variation in IOP, in glaucoma suspects and normal individuals in an African population.

MATERIALS AND METHODS

A cross-sectional analytical study was carried out between March and October 2019 at the University of Ilorin Teaching Hospital. A total of 204 study participants, comprising 102 primary open angle glaucoma (POAG) suspects and 102 age and sex-matched controls with healthy eyes were recruited. Participants had a comprehensive ophthalmic examination. Measurements of IOP were taken every 2 hours during a 24-hour period using an iCare tonometer.

RESULTS

The mean age was 43.64±14.02 SD and 43.02±13.55 SD ( P =1.000) for POAG suspects and controls, respectively. The mean peak IOP was significantly higher in POAG suspects (21.87± 4.65 mm Hg) compared with controls (17.17± 2.32 mm Hg) ( P <0.001). Whereas, the mean trough IOP reading was not significantly different between the 2 groups. In both groups of participants, the peak and trough IOP in the majority were recorded outside of clinic hours. The majority (68.9%) of POAG suspects had a peak IOP between midnight and 8 am, whereas the control group peaked mostly at 4 pm (16.7%) and 4 am (41.7%). Twenty-four-hour IOP variation was 6 mm Hg or less in 73.6% of control eyes, while in the POAG suspects, 83.3% of eyes had variation greater than 6 mm Hg.

CONCLUSIONS

Compared with age and sex-matched healthy controls, glaucoma suspects of African descent showed significantly higher mean IOP and IOP variation, with most peak IOP detected outside of clinic hours.

The Inflammasome-Dependent Dysfunction and Death of Retinal Ganglion Cells after Repetitive Intraocular Pressure Spikes

The dysfunction and selective loss of retinal ganglion cells (RGCs) is a known cause of vision loss in glaucoma and other neuropathies, where ocular hypertension (OHT) is the major risk factor. We investigated the impact of transient non-ischemic OHT spikes (spOHT) on RGC function and viability in vivo to identify cellular pathways linking low-grade repetitive mechanical stress to RGC pathology. We found that repetitive spOHT had an unexpectedly high impact on intraocular homeostasis and RGC viability, while exposure to steady OHT (stOHT) of a similar intensity and duration failed to induce pathology. The repetitive spOHT induced the rapid activation of the inflammasome, marked by the upregulation of NLRP1, NLRP3, AIM2, caspases -1, -3/7, -8, and Gasdermin D (GSDMD), and the release of interleukin-1β (IL-1β) and other cytokines into the vitreous. Similar effects were also detected after 5 weeks of exposure to chronic OHT in an induced glaucoma model. The onset of these immune responses in both spOHT and glaucoma models preceded a 50% deficit in pattern electroretinogram (PERG) amplitude and a significant loss of RGCs 7 days post-injury. The inactivation of inflammasome complexes in Nlrp1-/-, Casp1-/-, and GsdmD-/- knockout animals significantly suppressed the spOHT-induced inflammatory response and protected RGCs. Our results demonstrate that mechanical stress produced by acute repetitive spOHT or chronic OHT is mechanistically linked to inflammasome activation, which leads to RGC dysfunction and death.

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.

Twenty-Four-Hour Intraocular Pressure in Chronic Primary Angle-Closure Disease

PRCIS

Primary angle closure and primary angle closure glaucoma may exhibit normal intraocular pressure. Twenty-four-hour intraocular pressure fluctuation is highest in primary angle closure glaucoma. The degree of peripheral anterior synechiae was associated with a 24-hour intraocular pressure pattern in primary angle-closure disease without laser iridotomy.

PURPOSE

The purpose of this study was to study 24-hour intraocular pressure (IOP) patterns in eyes with chronic primary angle-closure disease and evaluate associations between peripheral anterior synechiae (PAS) and 24-hour IOP pattern.

PATIENTS AND METHODS

In this prospective cohort study, 59 eyes of 35 Asian patients with chronic primary angle-closure disease underwent complete ocular examinations at Ramathibodi Hospital, Mahidol University. Twenty-four-hour IOP records were obtained using Goldmann applanation tonometry at 2-hour intervals. Peak, mean, and trough 24-hour IOP values and 24-hour IOP fluctuation (difference between peak and trough values) were compared among groups. None of the participants received any treatment before complete data collection.

RESULTS

Even univariable analysis demonstrated a significant difference in peak, mean, and trough IOP and 24-hour IOP fluctuation between the 3 groups; the magnitude of trough IOP was not higher than 21 mmHg in all groups. In multivariable analysis, PAC and PACG eyes showed significantly higher peak IOP ( P =0.020 and 0.006, respectively) and 24-hour IOP fluctuation ( P =0.048 and 0.001, respectively) compared with PACS eyes. In comparison between combined PACS and PAC eyes versus PACG eyes, PACG eyes revealed significantly higher 24-hour IOP fluctuation. The degree of PAS was associated with peak and mean IOP values and with 24-hour IOP fluctuation in PAC and PACG eyes.

CONCLUSIONS

Twenty-four-hour IOP fluctuation was highest in PACG eyes. Although PAC and PACG eyes showed higher peak IOP and 24-hour IOP fluctuation values, compared with PACS eyes, trough IOP in PAC and PACG eyes were mostly below 21 mmHg. In addition, the degree of PAS was associated with a 24-hour IOP pattern in either PAC or PACG eyes.

Factors associated with choroidal microvascular dropout change

BACKGROUND/AIMS

To investigate the factors associated with choroidal microvasculature drop-out (MvD) enlargement detected by optical coherence tomography angiography (OCT-A) in glaucomatous eyes.

METHODS

Ninety-one eyes of 68 primary open-angle glaucoma patients were enrolled. Only eyes with a minimum of four good quality OCT-A and OCT scans of the optic nerve head acquired at least and with a minimum of 2 years follow-up were included. Area and angular circumference of MvD were analysed on en face images. Univariable and multivariable mixed effects models were constructed to identify the factors contributing to MvD area and angular circumference change over time.

RESULTS

Peripapillary MvD was detected in 53 (58.2%) eyes at baseline and in an additional 17 (18.6%) eyes during follow-up, whereas MvD was not detected in 21 (23.0 %) eyes during the entire follow-up period. In multivariable analysis, worse baseline visual field (VF) mean deviation (MD) (ß=0.27, 95% CI 0.10 to 0.44, p=0.002), greater intraocular pressure (IOP) fluctuations (ß=0.86, 95% CI 0.24 to 1.48, p=0.007), higher peak IOP (ß=0.17, 95% CI -0.01 to 0.35, p=0.067) and greater number of IOP lowering medications (ß=1.36, 95% CI 0.67 to 2.05, p<0.001) were associated with faster MvD area enlargement. Worse baseline VF MD and greater IOP fluctuation were also associated with significantly faster MvD circumferential enlargement in multivariable models.

CONCLUSION

Greater IOP fluctuation, higher peak IOP, worse baseline VF MD and greater number of glaucoma medications were significantly associated with MvD enlargement in glaucomatous eyes. The identification of factors associated with MvD enlargement may improve our understanding of the role of choroidal vasculature in glaucoma.

Clinical utility, feasibility of home tonometry using iCare HOME by glaucoma patients

Purpose

To determine agreement between diurnal variation testing (DVT) of intraocular pressure (IOP) with Goldmann applanation tonometer (GAT) and iCare HOME (IH) by an optometrist (OP) and home monitoring by participants (PT).

Methods

Patients (18-80 years) with glaucoma and suspects were enrolled. IH IOP and GAT were taken by an OP at 2 h intervals from 8 AM to 4 PM on Day 1 and PT between 6 AM and 9 PM, for the next 2 days. IOP, date, and time were viewed via iCare LINK software.

Results: In total,

72.9.

(

51/70) PT trained were able to take reliable readings. One hundred two eyes (51 patients, age 53 ± 16 yrs) were analyzed. Correlation between optometrist (OP) and participants (PT) was strong and positive {IH OP-IH PT- r = 0.90, p-0.0001;IH PT-GAT- r = 0.79, p-0.0001}. Agreement by Bland Altman plots was limited {IH OP-IH PT mean 0.1 mmHg (95% LOA -5.3 to 5.5), IH PT-GAT 2.2 mmHg (-5.7 to 10.1)}. Intraclass correlation coefficient for IH OP-IH PT was 1.18 (95% CI 1.37-1.09). Intradevice {0.95 (95% CI 0.94-0.97)} and interrater repeatability {0.91 (0.79-0.96)} were good. 37% of eyes had a synchronous peak on GAT and IH during the day DVT.

Conclusion

Home tonometry by iCare HOME is easy, feasible, but due to limited agreement cannot substitute GAT DVT.

Exploring the current use of animal models in glaucoma drug discovery: where are we in 2023?

INTRODUCTION

Animal models are widely used in glaucoma-related research. Since the elevated intraocular pressure (IOP) is a major risk factor underlying the disease pathogenesis, animal models with high IOP are commonly used. However, models are also used to represent the clinical context of glaucomatous changes developing despite a normal IOP.

AREAS COVERED

Herein, the authors discuss the various factors that contribute to the quality of studies using animal models based on the evaluation of studies published in 2022. The factors affecting the quality of studies using animal models, such as the animal species, age, and sex, are discussed, along with various methods and outcomes of studies involving different animal models of glaucoma.

EXPERT OPINION

Translating animal research data to clinical applications remains challenging. Our observations in this review clearly indicate that many studies lack scientific robustness not only in their experiment conduct but also in data analysis, interpretation, and presentation. In this context, ensuring the internal validity of animal studies is the first step in quality assurance. External validity, however, is more challenging, and steps should be taken to satisfy external validity at least to some extent.

Detection of Nocturnal Elevation in Intraocular Pressure Using a Home Tonometer in a Patient With Iridocorneal Endothelial Syndrome

We report on a patient with iridocorneal endothelial (ICE) syndrome in whom intraocular pressure (IOP) elevation during the night was detected using a home tonometer. A 44-year-old woman was diagnosed with ICE syndrome in the left eye. Angle-closure attack-like symptoms, including blurred vision and headache, appeared and spontaneously resolved irregularly at bedtime. Daytime examination indicated normal IOP and no obvious signs of glaucoma such as visual field defects or fundus abnormalities. However, nocturnal IOP measurements using a home tonometer revealed temporary high IOP at the time of symptom onset. A home tonometer may be a useful tool to detect transient IOP elevation at night, even if the IOP is normal during daytime examinations.

Sustained release ocular drug delivery systems for glaucoma therapy

INTRODUCTION

Glaucoma is a group of progressive optic neuropathies resulting in irreversible blindness. It is associated with an elevation of intraocular pressure (>21 mm Hg) and optic nerve damage. Reduction of the intraocular pressure (IOP) through the administration of ocular hypotensive eye drops is one of the most common therapeutic strategies. Patient adherence to conventional eye drops remains a major obstacle in preventing glaucoma progression. Additional problems emerge from inadequate patient education as well as local and systemic side effects associated with adminstering ocular hypotensive drugs.

AREAS COVERED

Sustained-release drug delivery systems for glaucoma treatment are classified into extraocular systems including wearable ocular surface devices or multi-use (immediate-release) eye formulations (such as aqueous solutions, gels; ocular inserts, contact lenses, periocular rings, or punctual plugs) and intraocular drug delivery systems (such as intraocular implants, and microspheres for supraciliary drug delivery).

EXPERT OPINION

Sustained release platforms for the delivery of ocular hypotensive drugs (small molecules and biologics) may improve patient adherence and prevent vision loss. Such innovations will only be widely adopted when efficacy and safety has been established through large-scale trials. Sustained release drug delivery can improve glaucoma treatment adherence and reverse/prevent vision deterioration. It is expected that these approaches will improve clinical management and prognosis of glaucoma.

Remote Contrast Sensitivity Testing Seems to Correlate With the Degree of Glaucomatous Macular Damage

PRCIS

Remote contrast sensitivity (CS) testing through a free downloadable home test correlates with glaucomatous macular damage measured by 10-2 visual field (VF) testing.

PURPOSE

To assess the feasibility and validity of home CS monitoring as a measure of glaucomatous damage using a free downloadable smartphone application.

METHODS

Twenty-six participants were asked to remotely use the Berkeley Contrast Squares (BCS) application, a free downloadable tool that records the user's CS for varying degrees of visual acuity. An instructional video detailing how to download and use the application was sent to the participants. Subjects were asked to send logarithmic CS results with a minimum 8-week test-retest window, and test-retest reliability was measured. Results were validated against office-based CS testing that was collected within the previous 6 months. Validity analysis was also carried out to determine whether CS as measured by BCS is a good predictor of 10-2 and 24-2 VF mean deviation (MD).

RESULTS

There was a high BCS test-retest reliability with an intraclass correlation coefficient score of 0.91 and a significant correlation between repeat test results and baseline test scores (Pearson, 0.86, P < 0.0001). There was significant agreement between unilateral CS scores as measured by BCS and office-based CS testing ( b = 0.94, P < 0.0001, 95% CI: 0.61 to 1.27). Unilateral CS as measured by BCS was significantly associated with 10-2 VF MD ( r2 = 0.27, P = 0.006, 95% CI: 3.7 to 20.6), but not with 24-2 VF MD ( P = 0.151).

CONCLUSION

This study suggests that a free, rapid home CS test correlates with glaucomatous macular damage as measured by 10-2 VF.

Outcomes of Selective Laser Trabeculoplasty After Prior Incisional Surgery for Open Angle Glaucoma

PRCIS

This retrospective case series of patients with open angle glaucoma and prior trabeculectomy or tube shunt surgery found that selective laser trabeculoplasty (SLT) resulted in significant intraocular pressure (IOP) reductions in the intermediate follow-up period in select cases.

PURPOSE

The purpose of this study was to assess the IOP-lowering effect and tolerability of SLT after prior trabeculectomy or tube shunt surgery.

MATERIALS AND METHODS

Open angle glaucoma patients at Wills Eye Hospital who previously underwent incisional glaucoma surgery and subsequently received SLT between 2013 and 2018 were included, along with an age-matched control group. Baseline characteristics, procedural data, and post-SLT data were recorded at 1, 3, 6, 12 months, and most recent visit. The primary success of SLT treatment was defined as IOP reduction of 20% or greater without the use of additional glaucoma medications compared to pre-SLT IOP. Secondary success was defined as IOP reduction ≥20% with the use of additional glaucoma medications compared to pre-SLT IOP.

RESULTS

There were 45 eyes in the study group and 45 eyes in the control group. In the study group, IOP decreased from a baseline of 19.5±4.7 mm Hg on 2.2±1.2 medications to 16.7±5.2 mm Hg ( P =0.002) on 2.2±1.1 glaucoma medications ( P =0.57). In the control group, IOP decreased from 19.5±4.2 mm Hg on 2.4±1.0 medications to 16.4±5.2 mm Hg ( P =0.003) on 2.1±1.3 medications ( P =0.36). There was no difference in IOP reduction or change in number of glaucoma medications after SLT at any postoperative visit between the 2 groups ( P ≥0.12 for all). Primary success rates at 12 months were 24.4% for the control group and 26.7% for the prior incisional glaucoma surgery group with no significant difference between the groups ( P =0.92). There were no persistent complications after SLT treatment in either group.

CONCLUSION

SLT may effectively lower IOP in patients with open angle glaucoma who have had previous incisional glaucoma surgery and should be considered in select cases.

Corneal Hysteresis for the Diagnosis of Glaucoma and Assessment of Progression Risk: A Report by the American Academy of Ophthalmology

PURPOSE

To review the current published literature on the utility of corneal hysteresis (CH) to assist the clinician in the diagnosis of glaucoma or in the assessment of risk for disease progression in existing glaucoma patients.

METHODS

Searches of the peer-reviewed literature in the PubMed database were performed through July 2022. The abstracts of 423 identified articles were examined to exclude reviews and non-English articles. After inclusion and exclusion criteria were applied, 19 articles were selected, and the panel methodologist rated them for level of evidence. Eight articles were rated level I, and 5 articles were rated level II. The 6 articles rated level III were excluded.

RESULTS

Corneal hysteresis is lower in patients with primary open-angle glaucoma, primary angle-closure glaucoma, pseudoexfoliative glaucoma, and pseudoexfoliation syndrome compared with normal subjects. Interpretation of low CH in patients with high intraocular pressure (IOP) or on topical hypotensive medications is complicated by the influence of these parameters on CH measurements. However, CH is also lower in treatment-naïve, normal-tension glaucoma patients compared with normal subjects who have a similar IOP. In addition, lower CH is associated with an increased risk of progression of glaucoma based on visual fields or structural markers in open-angle glaucoma patients, including those with apparently well-controlled IOP.

CONCLUSIONS

Corneal hysteresis is lower in glaucoma patients compared with normal subjects, and lower CH is associated with an increased risk of disease progression. However, a causal relationship remains to be demonstrated. Nevertheless, measurement of CH complements current structural and functional assessments in determining disease risk in glaucoma suspects and patients.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

FP and EP2 prostanoid receptor agonist drugs and aqueous humor outflow devices for treating ocular hypertension and glaucoma

Prostaglandin (PG) receptors represent important druggable targets due to the many diverse actions of PGs in the body. From an ocular perspective, the discovery, development, and health agency approvals of prostaglandin F (FP) receptor agonists (FPAs) have revolutionized the medical treatment of ocular hypertension (OHT) and glaucoma. FPAs, such as latanoprost, travoprost, bimatoprost, and tafluprost, powerfully lower and control intraocular pressure (IOP), and became first-line therapeutics to treat this leading cause of blindness in the late 1990s to early 2000s. More recently, a latanoprost-nitric oxide (NO) donor conjugate, latanoprostene bunod, and a novel FP/EP3 receptor dual agonist, sepetaprost (ONO-9054 or DE-126), have also demonstrated robust IOP-reducing activity. Moreover, a selective non-PG prostanoid EP2 receptor agonist, omidenepag isopropyl (OMDI), was discovered, characterized, and has been approved in the United States, Japan and several other Asian countries for treating OHT/glaucoma. FPAs primarily enhance uveoscleral (UVSC) outflow of aqueous humor (AQH) to reduce IOP, but cause darkening of the iris and periorbital skin, uneven thickening and elongation of eyelashes, and deepening of the upper eyelid sulcus during chronic treatment. In contrast, OMDI lowers and controls IOP by activation of both the UVSC and trabecular meshwork outflow pathways, and it has a lower propensity to induce the aforementioned FPA-induced ocular side effects. Another means to address OHT is to physically promote the drainage of the AQH from the anterior chamber of the eye of patients with OHT/glaucoma. This has successfully been achieved by the recent approval and introduction of miniature devices into the anterior chamber by minimally invasive glaucoma surgeries. This review covers the three major aspects mentioned above to highlight the etiology of OHT/glaucoma, and the pharmacotherapeutics and devices that can be used to combat this blinding ocular disease.

Abnormal Systemic and Ocular Responses to the Valsalva Manoeuvre in Primary Open-Angle Glaucoma: A Case for Autonomic Failure?

OBJECTIVE

This study aimed to examine the association of primary open-angle glaucoma (POAG) with autonomic dysfunction by assessing the differences in systemic and ocular responses to an autonomic provocation test, the Valsalva manoeuvre (VM), between POAG patients and normal subjects.

METHODS

Forty POAG and forty control subjects were subjected to the VM. Systemic and ocular parameters were measured at baseline, phase 2, and phase 4 of the VM (VM2 and VM4), where VM2 and VM4 are sympathetic and parasympathetic nervous activation states, respectively. Heart rate variability was used to assess the autonomic nervous activity, among which the high-frequency component (HF) and the low-frequency (LF)/HF ratio were used as indices of parasympathetic and sympathetic activation, respectively.

RESULTS

POAG patients demonstrated higher sympathetic activation (LF/HF ratio median: 2.17 vs. 1.53, P=0.000) than controls at baseline and exhibited attenuated sympathetic and parasympathetic responses (a smaller change in LF/HF and HF values) during the VM than controls. During VM, the intraocular pressure (IOP), mean blood pressure (MAP), mean ocular perfusion pressure (MOPP), and the Schlemm's canal area (SCAR) increased from baseline to VM2 and then decreased from VM2 to VM4 in both the POAG and control groups (all P<0.05). However, when we compared the changes above, the fluctuations in IOP, MAP, and MOPP were more pronounced in POAG than in controls (all P<0.05), while the changes in amplitudes of SCAR were smaller in POAG (P<0.05). Furthermore, from VM2 to VM4, the choroid thickness (ChT) in the POAG group was significantly decreased, while it was unchanged in normal subjects (P=0.258). A regression analysis showed a significant correlation of the baseline LF/HF with IOP change values (ΔIOP) from baseline to VM2 in POAG (R²=0.147, P=0.014).

CONCLUSION

Patients with POAG showed more pronounced fluctuations in IOP, MAP, MOPP and ChT during the VM than controls. These reactions could be associated with autonomic dysfunction in POAG.

The Effect of Combined Phacoemulsification and Endo-Cyclophotocoagulation on Intraocular Pressure Fluctuation Assessed by the Water Drinking Test in Patients with Primary Open Angle Glaucoma

INTRODUCTION

The aim of this study was to assess the effect of phacoemulsification and endo-cyclophotocoagulation (phaco-ECP) on intraocular pressure (IOP) fluctuation as assessed by the water drinking test (WDT) in primary open angle glaucoma (POAG).

METHODS

This was a prospective observational study carried out at a tertiary referral centre. POAG patients on topical antiglaucoma medications and planned for phaco-ECP were recruited. WDT was performed before surgery and 6 weeks postoperatively by drinking 10 mL/kg of water in 5 min followed by serial IOP by Goldmann applanation tonometry measurements at 15, 30, 45, and 60 min. Mean IOP, IOP fluctuation (difference between highest and lowest IOP), IOP reduction, and factors affecting IOP fluctuation were analysed.

RESULTS

Twenty eyes from 17 patients were included. Baseline IOP was similar before (14.7 ± 2.7 mm Hg) and after (14.8 ± 3.4 mm Hg, p = 0.90) surgery. There was no difference in mean IOP (17.6 ± 3.4 mm Hg vs. 19.3 ± 4.7 mm Hg pre- and postoperative, respectively, p = 0.26) or peak IOP (19.37 ± 3.74 mm Hg vs. 21.23 ± 5.29 mm Hg, p = 0.25), albeit a significant reduction in IOP-lowering medications (2.2 ± 1.15 vs. 0.35 ± 0.93, p < 0.001) postoperatively. IOP fluctuation was significantly greater (6.4 ± 3.2 mm Hg vs. 4.6 ± 2.1 mm Hg, p = 0.015) with more eyes having significant IOP fluctuation of ≥6 mm Hg (11 eyes [55%] vs. 4 eyes [20%], p < 0.001) postoperatively. Factors that were significantly associated with increased postoperative IOP fluctuations were higher preoperative IOP fluctuation (β = 0.69, 95% CI 0.379-1.582, p = 0.004) and more number of postoperative antiglaucoma medications (β = 0.627, 95% CI 0.614-3.322, p = 0.008).

CONCLUSION

Reducing aqueous production with phaco-ECP does not eliminate IOP fluctuation in POAG patients. The increase in postoperative IOP fluctuation suggests increased outflow resistance after phaco-ECP.

Impact of self-tonometry on glaucoma treatment decision

PURPOSE

The aim of this study was to examine the impact of self-tonometry on clinicians' decision in glaucoma treatment.

MATERIALS AND METHODS

Medical records of 133 patients who had performed self-tonometry using iCare^® Home between January and December 2019 were retrospectively reviewed. Inclusion criteria were as follows: age over 18 years, all types of glaucoma, as well as ocular hypertension and glaucoma suspect, compliance with tonometer manufacturer's recommendations and monitoring over at least 2 days. The data consisted of age, gender, diagnosis, visual field index, rate of progression and type of treatment pre- and post-intraocular pressure (IOP) phasing. The following IOP measurements were used to calculate the mean and maximum IOP, and range over each day and consecutive days: Goldmann applanation tonometry (GAT) measurements from referral and training visits and iCare^® Home measurements made by the trainers and the patients themselves. A total of 90 patients were included.

RESULTS

Clinicians were satisfied with the actual treatment in 54.4% of the cases. There was a statistically significant difference between the clinicians' decision to maintain same treatment or to escalate therapy for all the mean and maximum IOPs measured on each single day and over a 2- or 3-day period (p < 0.002).

CONCLUSION

Our results suggest that the presence of high IOP values obtained with self-tonometry supports an intensification of glaucoma treatment. Self-tonometry provides clinicians with an important complement for clinical decision-making, and under- or over-treatment may be avoided for the benefit of patients.

Basal ganglia lesions may be a risk factor for characteristic features of a glaucomatous optic disc: population-based cohort study in Japan

Background

We conducted a study to investigate the relationship between optic nerve vertical cup-to-disc ratio (VCDR), body and ocular parameters, and brain lesions in middle-aged and above Japanese subjects, because although various risk factors for glaucoma have been previously characterised, it is theorised that there are unidentified neurological components.

Methods

In this population-based, age/gender-stratified, cross-sectional study that involved 2239 Japanese subjects (1127 men and 1112 women) aged 40 years and older (mean age: 59.3±11.7 years) living in the central geographical region of Japan who participated in the National Institute of Longevity Sciences–Longitudinal Study of Aging between 2002 and 2004, 4327 eyes and 2239 obtained MRIs of the head were evaluated. Multivariate mixed model and trend analyses were also performed.

Results

No significant relationship between VCDR and brain lesions, other than basal ganglia lesions, was found. VCDR significantly increased with the high grade of basal ganglia infarct lesions (p=0.0193) and high intraocular pressure (p<0.0001) after adjustment for influential factors using a multivariate mixed model. A significant positive linear trend was observed between the predicted VCDR and the degrees of the basal ganglia lesions (p value trend=0.0096).

Conclusion

Our findings suggest that in subjects with higher grades of basal ganglia lesions, strict attention should be paid to elevated VCDR; however, further studies are needed to support/confirm our results.

Influence of the body positions adopted for resistance training on intraocular pressure: a comparison between the supine and seated positions

OBJECTIVES

A variety of factors are known to mediate on the intraocular pressure (IOP) response to resistance training. However, the influence of the body position adopted during resistance training on IOP remain unknown. The objective of this study was to determine the IOP response to the bench press exercise at three levels of intensity when performed in supine and seated positions.

METHODS

Twenty-three physically active healthy young adults (10 men and 13 women) performed 6 sets of 10 repetitions against the 10-RM (repetition maximum) load during the bench press exercise against three levels of intensity (high intensity: 10-RM load; medium intensity: 50% of the 10-RM load; and control: no external load) and while adopting two different body positions (supine and seated). A rebound tonometer was employed to measure IOP in baseline conditions (after 60 s in the corresponding body position), after each of the 10 repetitions, and after 10 s of recovery.

RESULTS

The body position adopted during the execution of the bench press exercise significantly affected the changes in IOP (p < 0.001, η_p² = 0.83), with the seated position providing lower increases in IOP levels compared to the supine position. There was an association between IOP and exercise intensity, with greater IOP values in the more physically demanding conditions (p < 0.001, η_p² = 0.80).

CONCLUSIONS

The use of seated positions, instead of supine positions, for the execution of resistance training should be prioritized for maintaining more stable IOP levels. This set of findings incorporates novel insights into the mediating factors on the IOP response to resistance training. In future studies, the inclusion of glaucoma patients would allow to assess the generalizability of these findings.

Caveolin-1 in vascular health and glaucoma: A critical vascular regulator and potential therapeutic target

Caveolin-1 (Cav-1) is an integral scaffolding membrane protein found in most cell types. Cav-1 has been found to contribute significantly to ocular function, with mutations of Cav-1 being associated with a genetic risk of glaucoma development. Raised intraocular pressure (IOP) is a major modifiable risk factor for glaucoma. Cav-1 may be involved in both IOP-dependent and independent mechanisms involving vascular dysregulation. Systemic vascular diseases including hypertension, diabetes and hyperlipidaemia, have been shown to be associated with glaucoma development. Cav-1 is closely interlinked with endothelial nitric oxide synthase pathways that mediate vascular function and prevent cardiovascular diseases. Endothelial nitric oxide synthase and endothelin-1 are key vasoactive molecules expressed in retinal blood vessels that function to autoregulate ocular blood flow (OBF). Disruptions in the homeostasis of OBF have led to a growing concept of impaired neurovascular coupling in glaucoma. The imbalance between perfusion and neuronal stimulation arising from Cav-1 depletion may result in relative ischemia of the optic nerve head and glaucomatous injury. OBF is also governed by circadian variation in IOP and systemic blood pressure (BP). Cav-1 has been shown to influence central BP variability and other circadian rhythms such as the diurnal phagolysosomal digestion of photoreceptor fragments and toxic substrates to maintain ocular health. Overall, the vast implications of Cav-1 on various ocular mechanisms leading to glaucoma suggest a potential for new therapeutics to enhance Cav-1 expression, which has seen success in other neurodegenerative diseases.

Detailed intraocular pressure curve by telemetric tonometry with an implanted pressure sensor before and after PreserFlo® MicroShunt implantation: a case report

Continuous control of intraocular pressure (IOP) is crucial to preventing long-term damage to the optic nerve in glaucoma. Recently, a novel telemetric IOP sensor (EYEMATE-IO™, Implandata Ophthalmic Products GmbH, Hannover, Germany) has been developed that continuously records IOP. The patient can read the IOP measurements wirelessly using a hand-held reading device. We present the case of a 70-year-old patient with primary open-angle glaucoma who had been implanted with an EYEMATE-IO™ and recently underwent minimally invasive bleb-filtering surgery with the PreserFlo^® MicroShunt (Santen, Osaka, Japan). This case demonstrates both the benefits of continuous pressure measurement with EYEMATE-IO™ and the ability of the PreserFlo^® MicroShunt to significantly reduce IOP fluctuations.

Relationship between Diurnal Variation in Intraocular Pressure and Central Corneal Power

SIGNIFICANCE

Relationship between intraocular pressure (IOP) change and central corneal curvature is complicated by measurement techniques and corneal biomechanical parameters. Findings from this study indicate that it is worthwhile to observe the association between diurnal change in IOP and corneal power.

PURPOSE

This study aimed to investigate the relationship between the diurnal change in IOP and central corneal power among eyes with and without myopia.

METHODS

Sixty healthy eyes of 24 emmetropes and 36 myopes were recruited for this cross-sectional study. Both anterior and posterior central corneal powers of the steep (Ks), flat (Kf), mean meridian (Km), best-fit spheres, and central corneal thickness were recorded followed by the IOP (Goldmann-correlated IOP [IOPg] and corneal-compensated IOP) and corneal biomechanics (corneal hysteresis and corneal resistance factor). Measurements were obtained every 3 hours from 9.30 am to 6.30 pm . Linear-mixed model was used to determine the relationship between the change in IOP and the associated change in corneal measurements (adjusted for age, sex, refractive error, central corneal thickness, and biomechanics) among the myopic and nonmyopic eyes.

RESULTS

Group mean, amplitude of change, and the diurnal change in IOPg were (mean ± standard deviation) 15.14 ± 2.50, 3.33 ± 1.44, and 1.81 ± 1.25 mmHg, respectively. Overall, an IOP increase was associated with a decrease in the adjusted anterior corneal powers. Myopic eyes were associated with a decrease of 0.04 D (95% confidence interval [CI], 0.07 to 0.01 D; P = .02) in Ks and 0.03 D (95% CI, 0.06 to 0.001 D; P = .047) in Kf per mmHg increase in IOP, whereas for emmetropes, per mmHg increase in IOP only flattened the Kf by 0.03 D (95% CI, 0.06 to 0.004 D; P = .02).

CONCLUSIONS

Change in anterior corneal power was inversely related to the change in IOPg, with myopic and nonmyopic eyes reporting a significant but differential impact of IOP. Clinicians must keep in mind the impact of large IOP fluctuation on the anterior corneal power.

[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.

Elevated IOP following a bladder filling protocol: A case report

Purpose

We describe a patient with elevated intraocular pressure (IOP) secondary to an oral water bolus and examine the utility of the water-drinking test.

Observations

A 66-year-old male with a history of hypertension presented with headache, bilateral retro-orbital ache, and blurry vision. Symptoms began shortly after his radiation treatment for prostate cancer, for which he consumed a water bolus to fill his bladder 30 minutes prior to treatment initiation. On exam, he had bilateral elevated IOP that responded to topical IOP-lowering medications. Gonioscopy demonstrated open angles and fundus exam showed non-glaucomatous optic nerves with pronounced retinal venous tortuosity. The water-drinking test showed a peak intraocular pressure of 20 mmHg in the right eye (5 mmHg increase from baseline) and 23 mmHg in the left eye (8 mmHg increase from baseline), suggesting impairment of the outflow system in the left compared to the right eye. He was started on topical IOP-lowering therapy and followed in our clinic as a glaucoma suspect.

Conclusions

Consumption of a water bolus can be associated with IOP elevation and may be a risk factor in patients with otherwise normal IOPs at risk for glaucoma. The water-drinking test was historically used as provocative testing for open-angle glaucoma and may have an updated role in evaluating at-risk patients without ocular hypertension.

Association of Intraocular Pressure With Retinal Nerve Fiber Layer Thinning in Patients With Glaucoma

Importance

Higher intraocular pressure variability may be associated with faster structural changes in patients with glaucoma.

Objectives

To investigate the association of mean intraocular pressure and intraocular pressure variability (defined as the SD of intraocular pressure and the intraocular pressure range) with the rate of retinal nerve fiber layer thinning over time in patients with glaucoma.

Design, Setting, and Participants

In this retrospective analysis of a longitudinal cohort, patients were enrolled from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation study. A total of 815 eyes (564 with perimetric glaucoma and 251 with preperimetric glaucoma) from 508 patients with imaging follow-up for a mean of 6.3 years from December 2008 to October 2020 were studied. Data were analyzed from November 2021 to March 2022.

Main Outcomes and Measures

In this longitudinal study, eyes with at least 4 visits and 2 years of follow-up optical coherence tomography and intraocular pressure measurement were included. A linear mixed-effect model was used to investigate the association of intraocular pressure parameters with the rates of retinal nerve fiber layer thinning. Dominance analysis was performed to determine the relative importance of the intraocular pressure parameters.

Results

Of 508 included patients, 280 (55.1%) were female, 195 (38.4%) were African American, 24 (4.7%) were Asian, 281 (55.3%) were White, and 8 (1.6%) were another race or ethnicity; the mean (SD) age was 65.5 (11.0) years. The mean rate of retinal nerve fiber layer change was -0.67 (95% CI, -0.73 to -0.60) μm per year. In multivariable models adjusted for mean intraocular pressure and other confounding factors, faster annual rate of retinal nerve fiber layer thinning was associated with a higher SD of intraocular pressure (-0.20[ 95% CI, -0.26 to -0.15] μm per 1-mm Hg higher; P < .001) or higher intraocular pressure range (-0.05 [95% CI, -0.06 to -0.03] μm per 1-mm Hg higher; P < .001).

Conclusions and Relevance

In this study, intraocular pressure variability was independently associated with structural change in patients with glaucoma, even after adjustment for mean intraocular pressure, supporting its potential value in clinical management.

Sustained release glaucoma therapies: Novel modalities for overcoming key treatment barriers associated with topical medications

Glaucoma is a progressive optic neuropathy and a leading cause of irreversible blindness. The disease has conventionally been characterized by an elevated intraocular pressure (IOP); however, recent research has built the consensus that glaucoma is not only dependent on IOP but rather represents a multifactorial optic neuropathy. Although many risk factors have been identified ranging from demographics to co-morbidities to ocular structural predispositions, IOP is currently the only modifiable risk factor, most often treated by topical IOP-lowering medications. However, topical hypotensive regimens are prone to non-adherence and are largely inefficient, leading to disease progression in spite of treatment. As a result, several companies are developing sustained release (SR) drug delivery systems as alternatives to topical delivery to potentially overcome these barriers. Currently, Bimatoprost SR (Durysta^TM) from Allergan plc is the only FDA-approved SR therapy for POAG. Other SR therapies under investigation include: bimatoprost ocular ring (Allergan) (ClinicalTrials.gov identifier: NCT01915940), iDose^® (Glaukos Corporation) (NCT03519386), ENV515 (Envisia Therapeutics) (NCT02371746), OTX-TP (Ocular Therapeutix) (NCT02914509), OTX-TIC (Ocular Therapeutix) (NCT04060144), and latanoprost free acid SR (PolyActiva) (NCT04060758). Additionally, a wide variety of technologies for SR therapeutics are under investigation including ocular surface drug delivery systems such as contact lenses and nanotechnology. While challenges remain for SR drug delivery technology in POAG management, this technology may shift treatment paradigms and dramatically improve outcomes.

Efficacy of selective laser trabeculoplasty on lowering intraocular pressure fluctuations and nocturnal peak intraocular pressure in treated primary open-angle glaucoma patients

Purpose

To investigate the efficacy of adjunctive selective laser trabeculoplasty (SLT) in reducing 24-h intraocular pressure (IOP) fluctuations and nocturnal IOP peaks.

Methods

In this prospective interventional case series, 157 medically treated eyes of 157 patients with primary open-angle glaucoma (POAG) who were assigned SLT to further reduce IOP were consecutively included. Each patient had a complete glaucoma work-up and 24-h IOP monitoring (6 measurements, including one in the supine position) taken before and on average 6 months after SLT. The main outcome measures were the reduction of 24-h IOP fluctuations and nocturnal peak IOP. Secondary outcome measures were success rates, factors influencing the reduction of high 24-h IOP fluctuations and nocturnal peak IOP, complications, and severe adverse events.

Results

Medicated mean 24-h IOP (mmHg) was statistically significantly reduced from 15.1 ± 2.6 to 13.8 ± 2.4 (P < 0.001) and IOP fluctuations from 6.5 ± 2.7 to 5.4 ± 2.6 (P < 0.001) 6 months after SLT. Ninety-four eyes (59.9%) initially had high IOP fluctuations (more than 5 mmHg). These were reduced from 8.1 ± 2.3 to 5.6 ± 2.7 at 6 months (P < 0.001). Fifty-two eyes (55.3%) had fluctuations below 5 mmHg post-SLT which was defined as success. Fifty-one patients (32.5%) had nocturnal IOP peaks. In these cases, nocturnal IOP was reduced by 19.2% from 20.1 ± 3.4 to 16.2 ± 3.3 mmHg at 6 months (P = 0.001).

Conclusions

The current study demonstrates that adjunctive SLT not only reduces mean 24-h IOP in treated POAG patients, but also has an additional benefit in reducing IOP fluctuations and nocturnal peak IOP.

Trial registration

Clinical trial registration: NCT02959242.

Progression of functional and structural glaucomatous damage in relation to diurnal and nocturnal dips in mean arterial pressure

Background

Systemic hypoperfusion plays a pivotal role in the pathogenesis of primary open-angle glaucoma (POAG). Extreme dips in mean arterial pressure (MAP) due to high 24-h variability are associated with POAG, however, whether this is driven by diurnal or nocturnal dips remains undocumented. We aimed this study to investigate the association of POAG damage with variability and dips in the diurnal and nocturnal MAP.

Methods

We conducted a retrospective longitudinal study that included 110 POAG patients who underwent 24-h ambulatory blood pressure monitoring. Our outcomes included (i) functional [visual field defects expressed as mean deviation (MD)] and (ii) structural (optic disc cupping obtained from cup-to-disc ratio) glaucoma damage. MAP variability independent of the mean (VIMmap) was computed for diurnal and nocturnal MAP. Dips were the five diurnal and three nocturnal lowest drops in MAP. We also calculated the night-to-day ratio. We applied mixed models to evaluate the progression of visual field defects and optic disc cupping in relation to diurnal and nocturnal MAP measures.

Results

The mean age was 64.0 y (53% women). The median follow-up was 9 years. In adjusted mixed models, functional progression of glaucoma damage was associated with VIMmap (−2.57 dB change in MD per every 3 mmHg increase in VIMmap; P &lt; 0.001) and diurnal MAP dips (changes in the MD ranged from −2.56 to −3.19 dB; P &lt; 0.001). Every 5 mmHg decrease in the nocturnal MAP level was associated with −1.14 dB changes in MD [95% confidence interval (CI), −1.90 to −0.40] and 0.01 larger optic disc cupping (95% CI, 0.01–0.02). Lower night-to-day ratio was also related to both outcomes (P ≤ 0.012). Functional glaucoma damage worsened if nocturnal hypotension was combined with high variability or extreme dips in the diurnal MAP (P ≤ 0.022).

Conclusion

Progression of glaucoma damage in POAG associates with high variability and extreme dips in the diurnal MAP. Structural glaucoma damage seems more vulnerable to nocturnal hypotension. Ambulatory blood pressure monitoring allows the assessment of sporadic diurnal and persistent nocturnal hypotension episodes. These phenotypes might offer an opportunity to improve the risk-stratification of open-angle glaucoma (OAG).

Diurnal Variation of Corneal Hysteresis in Patients With Untreated Primary Open Angle Glaucoma and Normal Individuals

PRCIS

Corneal hysteresis in both patients with untreated open angle glaucoma and normal individuals demonstrated significant diurnal variation independent of confounding factors and was higher in the nighttime than in the daytime.

PURPOSE

To investigate diurnal variations in corneal hysteresis (CH) in patients with untreated primary open angle glaucoma (POAG) and normal individuals by using an ocular response analyzer.

MATERIALS AND METHODS

This prospective study included 72 eyes of 53 patients with untreated POAG and 53 eyes of 47 normal individuals. Intraocular pressure (IOP) and CH were measured using Goldmann applanation tonometry (GAT) and ocular response analyzer, respectively, every 3 hours from 9:00 to 24:00. Mixed-effects models were used to determine factors associated with CH values and CH amplitude (maximum values minus minimum values) and to examine the diurnal variations in GAT IOP and CH in each group. Significant differences between time points were defined as significant variations.

RESULTS

The diurnal average GAT IOP and CH in patients with POAG were significantly higher and lower than those in normal individuals ( P =0.001, 0.002). In the multivariate analysis, the larger central corneal thickness was associated with larger CH values in POAG and normal eyes (both P <0.001). A larger amplitude of GAT IOP was significantly associated with a larger CH amplitude in POAG and normal eyes ( P =0.010, 0.013). CH, in both groups, showed similar significant diurnal variation and was higher in the nighttime than in the daytime, even after adjusting for confounding factors, while IOP showed an antiphase pattern.

CONCLUSION

CH in both untreated POAG patients and normal participants demonstrated similar diurnal variations, that is, higher at night, independent of confounding factors. These findings suggest that viscoelastic properties of the cornea may fluctuate diurnally independent of IOP.

Association of Ultra-Short-Term Intraocular Pressure Fluctuation With Disease Progression in Primary Angle Closure Glaucoma: The CUPAL Study

PRCIS

This study demonstrated significant differences in ultra-short-term IOP fluctuations, measured by a contact lens sensor between progressive and stable PACG eyes, during the first one hour after falling asleep.

PURPOSE

To identify the most sensitive period for detecting significant ultra-short-term intraocular pressure (IOP) fluctuation associated with disease progression in primary angle closure glaucoma (PACG).

MATERIALS AND METHODS

PACG eyes, which had been followed up for over 2 years under the CUHK PACG Longitudinal (CUPAL) Study, were recruited. Eyes with or without functional or structural glaucomatous progression were classified into 'progressive' or 'stable' groups on the basis of serial visual field and retinal nerve fiber layer (RNFL) thickness documentations, respectively. Ultra-short-term IOP fluctuations were recorded by Sensimed Triggerfish sensors (Sensimed AG, Lausanne, Switzerland) with 288 readings over 30 seconds, at 5-minute intervals, over a 24-hour period. In each of 7 activity-related 1-hour periods during the examining day, the mean value of the amplitude-frequency profiles of the signal fluctuations in twelve 30-second intervals was calculated by semivariogram/semi-variance. The 'progressive' and 'stable' groups were compared by permutation tests on functional t-statistics.

RESULTS

Among the 25 recruited PACG eyes, 16 eyes were classified as RNFL 'progressive' group (the mean rate of change in global RNFL thickness: -0.199 ±0.128 μm/mo). Higher signal fluctuations, in terms of amplitude-frequency, were found during the first 1-hour period of sleeping in the RNFL 'progressive' group compared with the RNFL 'stable' group ( P =0.028).

CONCLUSIONS

Between RNFL 'progressive' and 'stable' PACG eyes, significant differences in ultra-short-term IOP fluctuation at the 1-hour period after falling asleep were identified. The first hour of sleeping may be the most sensitive period for detecting significant ultra-short-term IOP fluctuation in PACG eyes.

Intraocular Pressure Measurements in Standing, Sitting, and Supine Position: Comparison between Tono-Pen Avia and Icare Pro Tonometers

Background: Intraocular pressure (IOP) is influenced by body position. The purpose of this study is to compare the IOP measurements obtained with two different devices, to investigate IOP changes in standing, sitting, and supine positions. Methods: In this comparative prospective case series, IOP was measured in sitting, supine, prone, and standing (standing 1) positions and again five minutes after standing (standing 2), utilizing an Icare Pro (ICP) and a Tono-Pen Avia (TPA) in the 64 eyes of 32 healthy subjects. Results: Compared to the sitting position, both devices showed an increase in the IOP both in supine and standing 2 positions (p < 0.05). The mean IOP difference between the two devices was: in the sitting position, 0.57 ± 2.10 mmHg (range: −3.80 to 6.60 mmHg) (p < 0.05), in the supine position, 0.93 ± 2.49 mmHg (range: −4.50 to 7.10 mmHg) (p < 0.05), in the standing 1 position, 0.37 ± 1.96 mmHg (range: −5.20 to 5.00 mmHg) (p = 0.102), and in the standing 2 position 0.73 ± 2.03 mmHg (range: −4.5 to 6.4 mmHg) (p < 0.001). Conclusions: The results highlight an agreement between the TPA and ICP, both confirming not only the increase in IOP in the supine position, but also showing an increase in the standing 2 position. Therefore, it is suggested to perform such measurements in patients with glaucoma, to explain its progression in an apparently normal tension or in compensated patients.

The IOP lowering effects of "planning" selective laser trabeculoplasty in open angle glaucoma

Purpose

To investigate whether the planning of selective laser trabeculoplasty (SLT) influences the intraocular pressure (IOP) in patients with open angle glaucoma (OAG).

Methods

In this retrospective case-control study conducted on patients with OAG who planned to undergo SLT treatment (SLT group) or a visual field examination (VF group), we collected the demographic data, IOP on the planning day and on the scheduled day of the SLT treatment or VF examination. ΔIOP was defined as the IOP change between the planning day and the scheduled day. We used multivariable regression analyses and linear mixed model to evaluate the association between the abovementioned factors and ΔIOP in the VF group and the treatment eye (SLT_t) and fellow eye (SLT_f) of the SLT group.

Results

One hundred and fifty-three eyes of 102 patients with OAG were included, of which 51 patients in the SLT group and 51 patients in the VF group. The ΔIOP was −1.92 ± 2.77 mmHg in the SLT_t, −0.65 ± 2.47 mmHg in the SLT_f and −0.08 ± 1.73 mmHg in the VF group (P < 0.05). Both multivariable regression analysis between the VF and SLT_t group and linear mixed model in the SLT group showed significant negative association between the ΔIOP and SLT arrangement (P < 0.05). There was no significant association between ΔIOP and age, gender, baseline IOP, IOP fluctuation, nor SE.

Conclusions

The IOP was significantly reduced in patients with OAG after “planning” of SLT treatment, even without actual performing the laser treatment in our retrospective case-control study.

Open-Angle Glaucomatous Optic Neuropathy Is Related to Dips Rather Than Increases in the Mean Arterial Pressure Over 24-H

BACKGROUND

Mean arterial pressure (MAP) drives ocular perfusion. Excessive 24-h MAP variability relates to glaucoma, however, whether this is due to dips or increases in the blood pressure (BP) is undocumented. We investigated the association of open-angle glaucoma (OAG) in relation to the 5 largest MAP dips/increases over 24-h, henceforth called dips/blips.

METHODS

In the Maracaibo Aging Study (MAS), 93 participants aged ≥40 y (women, 87.1%; mean age, 61.9 y) underwent baseline ophthalmological and 24-h ambulatory BP monitoring assessments. OAG was the presence of optic nerve damage and visual field defects. Statistical methods included logistic regression and the generalized R2 statistic. For replication, 48 OAG cases at the Leuven Glaucoma Clinic were matched with 48 controls recruited from Flemish population.

RESULTS

In the MAS, 26 participants had OAG. OAG compared to non-OAG participants experienced longer and deeper dips (116.5 vs. 102.7 minutes; to 60.3 vs. 66.6 mm Hg; -21.0 vs. -18.0 mm Hg absolute or 0.79 vs. 0.81 relative dip compared to the preceding reading). The adjusted odds ratios associated with dip measures ranged from 2.25 (95% confidence interval [CI], 1.31-4.85; P = 0.009) to 3.39 (95% CI, 1.36-8.46; P = 0.008). On top of covariables and 24-MAP level/variability, the dip measures increased the model performance (P ≤ 0.025). Blips did not associate with OAG. The case-control study replicated the MAS observations.

CONCLUSIONS

Dips rather than increases in the 24-h MAP level were associated with increased risk for OAG. An ophthalmological examination combined with 24-h BP monitoring might be precautious steps required in normotensive and hypertensive patients at risk of OAG.

Hemoglobin Video Imaging Detects Differences in Aqueous Outflow Between Eyes With and Without Glaucoma During the Water Drinking Test

PRCIS

Hemoglobin video imaging (HVI) demonstrates increased aqueous outflow (AO) in response to the water drinking test (WDT) in patients with and without glaucoma. In glaucomatous eyes, increased AO was not sustained, and characteristic flow patterns were seen.

PURPOSE

To observe how variations in intraocular pressure (IOP) correlate with the flow of aqueous in episcleral veins.

DESIGN

Prospective observational cohort study.

PARTICIPANTS

The WDT increased AO into the episcleral venous system in 30 eyes recruited from Sydney Eye Hospital. A comparison was made between glaucomatous (n=20) and nonglaucomatous eyes (n=10).

METHODS

Each patient had baseline IOP and HVI before drinking 10 mL/kg body weight of water. IOP and HVI were then repeated every 15 minutes for 1 hour. Aqueous column cross-sectional area (AqCA) of the most prominent nasal and temporal aqueous veins was used to semi-quantify conventional AO.

MAIN OUTCOME MEASURES

Change in IOP and AqCA from baseline during the WDT. Aqueous flow characteristics were also observed.

RESULTS

Peak IOP elevation above baseline was significantly higher in the glaucoma group, with an average IOP rise of 39.7% on 1.6 1.1 medications, compared with 22.9% in the control group ( P =0.04). AqCA significantly increased for glaucomatous and nonglaucomatous eyes in response to water ingestion ( P <0.05). AqCA fell by 50% in glaucomatous eyes ( P =0.003) and 33% in nonglaucomatous eyes ( P =0.08) at study completion compared with the peak measurement. IOP remained >30% elevated in 8 glaucomatous eyes (40%) after 60 minutes and no control eyes. Variations in qualitative aqueous flow patterns were observed in glaucomatous eyes but not in controls.

CONCLUSIONS

AO volume, estimated by AqCA, increases in response to IOP elevation induced by an ingested water bolus in patients with and without glaucoma. The increase in aqueous drainage was not sustained in glaucomatous eyes and may have led to incomplete recovery of IOP. Using HVI in combination with the WDT may assist with clinical decision-making and facilitate the monitoring of responses to treatment.

Effect of Mindfulness-Based Stress Reduction on Intraocular Pressure in Patients With Ocular Hypertension: A Randomized Control Trial

PURPOSE

To evaluate the effect of mindfulness-based stress reduction (MBSR) on intraocular pressure (IOP) in patients with ocular hypertension (OHT).

DESIGN

Parallel arm, single masked, randomized controlled trial.

METHODS

Sixty patients with ocular hypertension and IOP > 21 and < 30 mmHg were recruited at a tertiary eye care centre in India. Thirty patients (group 1) underwent six weeks of one hour daily MBSR sessions, while the other 30 patients (group 2) were waitlisted and kept on follow-up. The primary outcome was change in IOP (ΔIOP) after six weeks of MBSR. Secondary outcomes were effect on serum cortisol level, diurnal variation of IOP, vessel perfusion and vessel density on optical coherence tomography angiography (OCTA), and quality of life (QOL).

RESULTS

At six weeks, a significant decrease in IOP was noted in group 1 (23.05 ± 1.17 to 19.15 ± 1.45 mmHg; P = .001) compared with group 2 (22.55 ± 0.98 mmHg to 22.37 ± 1.07 mmHg; P = .107). The ΔIOP was significantly greater in group 1 (3.93 ± 1.47) than group 2 (0.17 ± 0.58; P = .001). The diurnal fluctuation of IOP decreased in group 1 (4.87 ± 1.13 mmHg to 2.73 ± 0.98 mmHg; P = .001) as compared with group 2 (4.50 ± 0.86 mmHg to 4.30 ± 0.83 mmHg; P = .227). Significant improvement in vessel perfusion, vessel density, and flux index was noted on OCTA in group 1 compared with group 2. Group 1 showed a significant decrease (P ≤ .001) in serum cortisol level and an improved QOL (P = .001).

CONCLUSION

Mindfulness-based stress reduction was associated with a significant decrease in IOP and serum cortisol, along with an improvement in optic nerve head perfusion and QOL. Mindfulness-based stress reduction can be considered as a potential treatment option in the management of OHT.

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.

Evaluation of Spatially Targeted Scleral Stiffening on Neuroprotection in a Rat Model of Glaucoma

Purpose

Scleral stiffening may protect against glaucomatous retinal ganglion cell (RGC) loss or dysfunction associated with ocular hypertension. Here, we assess the potential neuroprotective effects of two treatments designed to stiffen either the entire posterior sclera or only the sclera adjacent to the peripapillary sclera in an experimental model of glaucoma.

Methods

Rat sclerae were stiffened in vivo using either genipin (crosslinking the entire posterior sclera) or a regionally selective photosensitizer, methylene blue (stiffening only the juxtaperipapillary region surrounding the optic nerve). Ocular hypertension was induced using magnetic microbeads delivered to the anterior chamber. Morphological and functional outcomes, including optic nerve axon count and appearance, retinal thickness measured by optical coherence tomography, optomotor response, and electroretinography traces, were assessed.

Results

Both local (juxtaperipapillary) and global (whole posterior) scleral stiffening treatments were successful at increasing scleral stiffness, but neither provided demonstrable neuroprotection in hypertensive eyes as assessed by RGC axon counts and appearance, optomotor response, or electroretinography. There was a weak indication that scleral crosslinking protected against retinal thinning as assessed by optical coherence tomography.

Conclusions

Scleral stiffening was not demonstrated to be neuroprotective in ocular hypertensive rats. We hypothesize that the absence of benefit may in part be due to RGC loss associated with the scleral stiffening agents themselves (mild in the case of genipin, and moderate in the case of methylene blue), negating any potential benefit of scleral stiffening.

Translational Relevance

The development of scleral stiffening as a neuroprotective treatment will require the identification of better tolerated stiffening protocols and further preclinical testing.

The Effect of Autonomic Nervous System Dysfunction on the Progression of Primary Open-Angle Glaucoma

Purpose

To study the effect of autonomic nervous system (ANS) dysfunction on glaucoma progression in patients with primary open angle glaucoma (POAG).

Patients and Methods

A retrospective study of 40 cases of POAG patients who underwent regular reexamination for more than 3 years was performed. All participants were subjected to heart-rate variability (HRV) assessment. Patients were divided equally into the lowest and highest HRV groups according to the standard deviation value of the qualified normal to normal intervals (SDNN), a representative indicator of HRV. The lower the HRV, the more severe the ANS dysfunction with sympathetic predominance. Visual field (VF) parameters and retinal nerve fiber layer (RNFL) thickness were used to evaluate and compare the progression of glaucoma damage between the two groups.

Results

There were 20 cases in the lowest HRV group and 20 cases in the highest HRV group. The thinning rate of RNFL in the lowest HRV group was significantly faster than that in the highest HRV group (1.44±1.58 vs 0.29±0.56 μm/year, P=0.00), accompanied by greater fluctuation of intraocular pressure (IOP) (P=0.04), lower diastolic blood pressure (P=0.01), mean blood pressure (P=0.04), and lower mean ocular perfusion pressure (P=0.04). Meanwhile, the incidence of central VF defects in the lowest HRV group was significantly higher than that in the highest HRV group (65.0% vs 30%, P=0.03). Linear regression analysis showed that there was a significant correlation between SDNN and the thickness loss rate of RNFL (P=0.01).

Conclusion

POAG patients with lower HRV, which reflects ANS dysfunction with sympathetic predominance, presented faster glaucoma progression than patients with higher HRV. The more rapid progression of POAG with lower HRV may be explained by IOP and vascular risk factors.

2-Jahres-Ergebnisse nach transskleraler MicroPulse-Lasertherapie bei Patienten mit primärem Offenwinkelglaukom

Hintergrund Untersuchung der langfristigen Effizienz und Sicherheit der transskleralen Lasertherapie (TLT) mittels MicroPulse über 24 Monate bei Patienten mit primärem Offenwinkelglaukom (POWG).

Material und Methoden In dieser prospektiven interventionellen Fallserie wurden die Daten von 44 Augen von medikamentös behandelten POWG-Patienten ausgewertet, die eine MicroPulse-TLT erhielten, um eine weitere Senkung des Augeninnendrucks (IOD) zu erreichen. Es wurden die Reduktion des 24-h-IODs, der zirkadianen IOD-Fluktuationen und der IOD-Spitzen nach 3, 12 und 24 Monaten untersucht. Zudem sollten postoperative Komplikationen, die Misserfolgsquote und Einflussfaktoren auf den Therapieerfolg analysiert werden.

Ergebnisse Der IOD ist von 16,1 ± 3,4 mmHg präoperativ auf 13,0 ± 2,9 mmHg (n = 31; p < 0,001) nach 3 Monaten, 12,3 ± 3,0 mmHg (n = 27; p < 0,001) nach 12 Monaten und 13,1 ± 2,6 mmHg (n = 23; p < 0,001) nach 24 Monaten gesunken. Nach 24 Monaten erreichten 23 Augen (52%) ihren individuellen Zieldruck. Es traten keine schwerwiegenden postoperativen Komplikationen auf. Es konnten keine Einflussfaktoren auf den Therapieerfolg identifiziert werden. Das häufigste Therapieversagen war innerhalb der ersten 3 postoperativen Monate zu beobachten und blieb danach nahezu stabil.

Schlussfolgerung Die MicroPulse-TLT zeigt eine gute IOD-Senkung bei Patienten mit primärem Offenwinkelglaukom und maximal tolerierter drucksenkender Lokaltherapie, wobei etwa 50% der Augen ihren individuellen Zieldruck erreichten.

Dual Orexin Receptor Antagonist Attenuates Increases in IOP, ICP, and Translaminar Pressure Difference After Stimulation of the Hypothalamus in Rats

PURPOSE

Intraocular pressure (IOP) remains the only modifiable risk factor for glaucoma progression. Our previous discovery that stimulation of nuclei within the hypothalamus can modulate IOP, intracranial pressure (ICP), and translaminar pressure difference (TLPD) fluctuations led us to investigate this pathway further. Our purpose was to determine the role of orexin neurons, primarily located in the dorsomedial hypothalamus (DMH) and perifornical (PeF) regions of the hypothalamus, in modulating these pressures.

METHODS

Sprague Dawley rats were pretreated systemically with a dual orexin receptor antagonist (DORA-12) at 30 mg/Kg (n = 8), 10 mg/Kg (n = 8), or vehicle control (n = 8). The IOP, ICP, heart rate (HR), and mean arterial pressure (MAP) were recorded prior to and following excitation of the DMH/PeF using microinjection of the gamma-aminobutyric acid (GABA)A receptor antagonist bicuculline methiodide (BMI).

RESULTS

Administration of the DORA at 30 mg/Kg significantly attenuated peak IOP by 5.2 ± 3.6 mm Hg (P = 0.007). During the peak response period (8-40 minutes), the area under the curve (AUC) for the 30 mg/Kg DORA cohort was significantly lower than the control cohort during the same period (P = 0.04). IOP responses for peak AUC versus DORA dose, from 0 to 30 mg/Kg, were linear (R2 = 0.18, P = 0.04). The ICP responses during the peak response period (4-16 minutes) versus DORA dose were also linear (R2 = 0.24, P = 0.014). Pretreatment with DORA significantly decreased AUC for the TLPD following stimulation of the DMH/PeF (10 mg/kg, P = 0.045 and 30 mg/kg, P = 0.015).

CONCLUSIONS

DORAs have the potential to attenuate asynchronous changes in IOP and in ICP and to lessen the extent of TLPDs that may result from central nervous system (CNS) activation.