Intraocular Pressure Elevation In Eyes Research Articles

Corneal Biomechanical Changes Caused by Acute Elevation of IOP in Eyes with and without Glaucoma.

Although corneal biomechanical parameters are well linked with glaucoma, their clinical utility has not yet been fully elucidated. This study was designed to provide unique evidence about the dynamic nature of corneal biomechanical parameters and their potential prognostic ability for glaucoma. This study aimed to evaluate the effect of acute intraocular pressure (IOP) elevation on corneal hysteresis (CH) and corneal resistance factor (CRF) and the associations of these biomechanical parameters with glaucomatous disease. Subjects participating in a prospective, longitudinal glaucoma research study had CH and CRF measured before and during ophthalmodynamometry during visits in the years 2011 to 2012. All participants were diagnosed with primary open-angle glaucoma, ocular hypertension, glaucoma suspect, or normal eyes and had a minimum of 3 years of study participation with at least five reliable visual field (VF) tests. Changes in CH, CRF, and IOP induced by ophthalmodynamometry were compared between diagnostic groups and evaluated for relationships with existing and future glaucomatous VF loss. In 248 eyes of 248 subjects followed up for 7.7 ± 2.3 years, ophthalmodynamometry induced a mean IOP increase from 15.1 to 29.9 mmHg, causing a mean 34 ± 28% increase in CRF and 21 ± 25% decrease in CH. Magnitude of CH change did not differ between diagnostic groups or between eyes that did (n = 20) and did not (n = 95) develop new VF loss during the study period, nor was it related to rate of future VF progression. Ophthalmodynamometry-induced IOP elevation resulted in significant acute changes in CH and CRF in this study; this suggests accounting for IOP may be important in clinical interpretation of these parameters. However, because the degree of CH change was not related to glaucoma or its progression, acute changes in CH and CRF do not seem to have a prognostic value for glaucoma.

Modeling a potential SANS countermeasure by experimental manipulation of the translaminar pressure difference in mice

The spaceflight-associated neuro-ocular syndrome (SANS), which may present after prolonged exposure to microgravity, is thought to occur due to elevated intracranial pressure (ICP). Intracranial pressure interacts with intraocular pressure (IOP) to define the translaminar pressure difference (TLPD; IOP−ICP). We combined inducible models of ICP and IOP elevation in mice to interrogate the relationships among ICP, IOP, and TLPD, and to determine if IOP elevation could mitigate the phenotypes typically caused by elevated ICP and thereby serve as a countermeasure for SANS. Ten C57BL6J mice of both genders underwent experimental elevation of ICP via infusion of artificial cerebrospinal fluid into the subarachnoid space. One eye also underwent experimental elevation of IOP using the bead injection model. Intraocular pressure and ICP were monitored for 2 weeks. Optokinetic-based contrast sensitivity was measured at baseline and after 2 weeks, and post-mortem studies of optic nerve and retina anatomy were performed. Photopic contrast sensitivity was reduced more in IOP elevated than control eyes. Scotopic contrast sensitivity was reduced similarly in IOP elevated and control eyes. However, the pattern of scotopic vision loss was not uniform in IOP elevated eyes; there was minimal loss in eyes that most closely approximated the normal TLPD. Optic nerve axon loss, increased optic nerve disorganization, and retinal ganglion cell loss all occurred similarly between IOP elevated and control eyes. Elevation of IOP in eyes with elevated ICP may counterbalance some effects on vision loss but exacerbate others, suggesting complex relationships among IOP, ICP, and TLPD.

Long-term probability of intraocular pressure elevation with the intravitreal dexamethasone implant in the real-world.

PurposeTo evaluate the long-term cumulative probability of intraocular pressure (IOP) elevation with the intravitreal dexamethasone implant (IDI) when used to treat different indications: diabetic macular edema, uveitis, retinal vein occlusion.Methods705 IDI injections (429 eyes) were assessed and Kaplan-Meier graphs were generated to assess: the probability of different levels of IOP elevation (IOP≥21, ≥25 or ≥35 mmHg), IOP change ≥10 mmHg, initiation of IOP-lowering treatment, glaucoma surgery, IOP change with repeat injections and IOP elevation in eyes with glaucoma and ocular hypertension (OHT).ResultsThe cumulative probability of IOP ≥21, ≥25 and ≥35 mmHg was 50%-60%, 25%-30% and 6%-7% at 12–24 months, respectively. The probability of initiating IOP-lowering medication was 31%-54% at 12–24 months. Glaucoma and OHT eyes had a higher probability of mild IOP elevation (≥21 mmHg, 65.1%, 75% and 57.8%, p = 0.01), yet a similar moderate (≥25 mmHg, 22.3%, 28% and 30.2%, p = 0.91) and severe elevation of IOP (≥35 mmHg, 3.7%, 7.1% and 4%, p = 0.71) as normal eyes. Glaucoma surgery was required in only 0.9% cases (4/429). At baseline, 8.8% of the treated eyes had glaucoma, 6.7% OHT and 16.9% were already on IOP-lowering medication.ConclusionsIn the long-term (24 months), IOP elevation is common, generally mild (30% IOP, ≥25 mmHg) and well-tolerated, resolving with topical treatment (54%) and rarely requiring surgery (0.9%).

In vivo assessment of changes in corneal hysteresis and lamina cribrosa position during acute intraocular pressure elevation in eyes with markedly asymmetrical glaucoma.

PurposeTo investigate the biomechanical response of the cornea, lamina cribrosa (LC), and prelaminar tissue (PT) to an acute intraocular pressure (IOP) increase in patients with markedly asymmetrical glaucoma and in healthy controls.Patients and methodsA total of 24 eyes of 12 patients with markedly asymmetrical primary open-angle glaucoma (POAG) and 12 eyes of 12 healthy patients were examined with spectral-domain optical coherence tomography (SD-OCT) and ocular response analyzer (ORA) at baseline and during acute IOP elevation by means of an ophthalmodynamometer. The displacement of the LC and PT and the change in corneal hysteresis (CH) and corneal resistance factor (CRF) were evaluated.ResultsFollowing a mean IOP increase of 12.3±2.4 mmHg, eyes with severe glaucoma demonstrated an overall mean anterior displacement of the LC (−6.58±26.09 µm) as opposed to the posterior laminar displacement in eyes with mild glaucoma (29.08±19.28 µm) and in healthy eyes (30.3±10.9; p≤0.001 and p=0.001, respectively). The PT displaced posteriorly during IOP elevation in all eyes. The CH decreased in eyes with severe glaucoma during IOP elevation (from 9.30±3.65 to 6.92±3.04 mmHg; p=0.012), whereas the CRF increased markedly in eyes with mild glaucoma (from 8.61±2.30 to 12.38±3.64; p=0.002) and in eyes with severe glaucoma (from 9.02±1.48 to 15.20±2.06; p=0.002). The increase in CRF correlated with the anterior displacement of the LC in eyes with severe glaucoma.ConclusionEyes with severe glaucoma exhibited a mean overall anterior displacement of the anterior laminar surface, while eyes with mild glaucoma and healthy eyes showed a posterior displacement of the LC during IOP elevation. The CH decreased significantly from baseline only in eyes with severe glaucoma, but the CRF increased significantly in all glaucomatous eyes. The CRF increase correlated with the anterior displacement of the LC in eyes with severe glaucoma.

Sustained intraocular pressure elevation in eyes treated with intravitreal injections of anti-vascular endothelial growth factor for diabetic macular edema in a real-life setting.

The aim of this study was to investigate the sustained intraocular pressure (IOP) elevation after repeated anti-VEGF intravitreal injections (IVI) in patients with diabetic macular edema (DME). A retrospective study included 140 eyes without prior glaucoma, treated with at least three anti-VEGF injections for DME between 2012 and 2016. IOP elevation was defined by an increase above baseline IOP by ≥6mmHg. Baseline IOP was defined as the mean of IOP values before treatment initiation. Three groups were differentiated: group 1 without IOP elevation, groups 2 and 3 with IOP elevation and IOP <21mmHg (group 2) and ≥21mmHg (group 3). Rate and several risk factors of IOP elevation were assessed and compared between the three groups. IOP elevation occurred in ten eyes (7.1%). IOP was <21mmHg in six eyes and ≥21mmHg in four eyes. Statistically significant associations were found between IOP elevation and the number of injections, and HbA1c level. Two patients required local hypotonic treatment. In a real-life setting, we confirmed in eyes with center-involved DME without prior glaucoma or IOP elevation that repeated anti-VEGF IVI may increase the risk of sustained IOP elevation in about 7% of eyes.

Predictors of Sustained Intraocular Pressure Elevation in Eyes Receiving Intravitreal Anti–Vascular Endothelial Growth Factor Therapy

To determine the intravitreal anti-vascular endothelial growth factor (VEGF) injection techniques and preferences within the retinal community and to identify potential factors associated with the development of sustained intraocular pressure (IOP) elevation in patients treated with intravitreal anti-VEGF therapy for neovascular age-related macular degeneration (AMD). Cross-sectional physician survey. Five hundred and thirty retina specialists spanning both private and academic practices were surveyed regarding current anti-VEGF intravitreal injection protocols, including the anti-VEGF drug of choice, needle gauge, injection volume, injection technique, and self-reported prevalence of sustained IOP elevation. Multivariate logistic regressions were performed to assess the potential influence of these factors on long-term IOP. Two hundred ninety-two specialists (55%) reported believing that intravitreal anti-VEGF therapy may cause sustained IOP elevation. Of these responses, the most common reported prevalence was 1%-2% (48%), followed by 3%-5% (34%). There was no relationship between the frequency of sustained IOP elevation and anti-VEGF drug of choice. Physicians who injected greater than 0.05 cc in less than 1 second were 5.56 times more likely to observe a high frequency of sustained IOP elevation (P=.006, 95% CI 1.64-18.89). Based on physician survey data, serial anti-VEGF injections using higher injection volumes with a rapid injection technique may potentially lead to sustained IOP elevation. The underlying mechanism for this complication may be injury to the trabecular meshwork resulting from rapid elevations in IOP. Further investigation of the relationship between injection techniques and sustained IOP elevation in the form of retrospective or prospective clinical studies is warranted.

CLINICAL PREDICTORS OF SUSTAINED INTRAOCULAR PRESSURE ELEVATION DUE TO INTRAVITREAL ANTI–VASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY

We assess for frequency and predictive factors related to sustained intraocular pressure (IOP) elevation in eyes with neovascular age-related macular degeneration receiving intravitreal injections of ranibizumab and/or bevacizumab. A total of 328 patients with neovascular age-related macular degeneration (449 eyes) who presented to a single physician over a 6-month period were retrospectively assessed for baseline demographic/clinical information, total number of bevacizumab and/or ranibizumab injections, and sustained IOP elevation on 2 or more consecutive visits (absolute IOP >25 mmHg, increase above baseline >10 mmHg, or IOP of >21 mmHg and increase of >5 mmHg). Cox regression survival analysis and multivariate logistic regression were performed to assess the influence of intravitreal injections on experiencing sustained IOP elevation. Overall, 32 eyes (7.1%) experienced sustained IOP elevation. Survival analysis showed a significant effect of the number of anti-vascular endothelial growth factor injections on sustained IOP elevation (hazard ratio, 1.085; 95% confidence interval: 1.06-1.11, P < 0.001). Also, there was an increased odds ratio (16.1, P = 0.008) of sustained IOP elevation in eyes receiving ≥29 injections compared with ≤12 injections. After controlling for the confounder (prior intravitreal steroid injection), total number of injections still showed a statistically significant association (P = 0.002). A greater number of intravitreal anti-vascular endothelial growth factor injections is associated with an increased risk for sustained IOP elevation in eyes with neovascular age-related macular degeneration receiving intravitreal ranbizumab and/or bevacizumab.

Frequency and Risk Factors for Intraocular Pressure Elevation After Posterior Sub-Tenon Capsule Triamcinolone Acetonide Injection

This study investigated the effects of posterior sub-Tenon capsule (PST) injection of triamcinolone acetonide (TA) on intraocular pressure (IOP) in the human eye. The study included 115 patients who received PST injections of 40-mg TA to treat macular edema with diabetic retinopathy (n=57), branch retinal vein occlusion (n=35), central retinal vein occlusion (n=13), or other disorders (n=10). IOP measurements were performed on the day of injection, and 0.5, 1, 2, 3, 6, 9, and 12 months later. In 26 (22.6%) of the 115 eyes, an IOP of 24 mm Hg or higher was observed during the 12-month follow-up period after PST TA injection. IOP elevation significantly correlated with young age, but not with past history of diabetes mellitus or systemic hypertension, sex, or type of retinal disease with macular edema. In total, 23 eyes were treated with antiglaucoma medications to control elevated IOP (24 mm Hg or higher). External trabeculotomy was performed in 1 case where medications failed to correct elevated IOP. PST TA injection is associated with high rates of steroid-induced IOP elevation in eyes with previously normal IOP. However, IOP elevation may be less common after PST injection than after intravitreal injection. Our findings indicate that IOP must be carefully monitored after PST TA injection.

Selective Laser Trabeculoplasty (SLT) Complicated by Intraocular Pressure Elevation in Eyes With Heavily Pigmented Trabecular Meshworks

To report and assess the complication of intraocular pressure (IOP) elevations after selective laser trabeculoplasty (SLT) in patients with heavily pigmented trabecular meshworks. Noncomparative, observational case series. Retrospective analysis of the medical files of four glaucoma patients with heavily pigmented trabecular meshwork, who presented with IOP elevations after SLT. All four glaucoma patients presented with post-SLT IOP elevations. Three had features of pigmentary dispersion syndrome, and the fourth had a heavily pigmented trabecular meshwork. Two patients had previous argon laser trabeculoplasty (ALT) in the same eye in which SLT was performed, and one had a previous ocular trauma. Eventually, three of the patients required surgical trabeculectomy. This case series suggests that post-SLT IOP elevations can be a serious adverse event in some glaucomatous patients. It is recommended by the authors that patients with a deeply pigmented trabecular meshwork, taking multiple topical medications and having previous ALT treatment, should be considered at higher risk for this complication.

Prevalence and Mechanisms of Secondary Intraocular Pressure Elevation in Eyes with Intraocular Tumors

A survey of 2704 eyes with intraocular tumors in patients who were evaluated on the Oncology Service at Wills Eye Hospital showed that 126 of the tumor-containing eyes (5%) had tumor-induced elevated intraocular pressure (IOP) at the time of diagnosis of the tumor. Of the 2111 eyes with uveal melanomas, secondary IOP elevation was present in 55 (3%). Secondary IOP elevation was present in 7% of eyes with iris melanoma, 17% with ciliary body melanoma, and 2% with choroidal melanoma. The most common mechanism of elevated IOP was tumor invasion of the angle in the case of iris melanomas, pigment dispersion and tumor invasion of the angle in the case of ciliary body melanomas, and iris neovascularization in the case of choroidal melanomas. Of the 256 eyes with uveal metastases, secondary IOP elevation was found in 12 eyes (5%). Secondary IOP elevation was present in 64% of eyes with iris metastases, 67% with ciliary body metastases, and 1 % with choroidal metastases. The most common mechanism of elevated IOP was tumor invasion of the angle in the case of iris and ciliary body metastases, and angle closure in the case of choroidal metastases. There were 303 eyes with retinoblastoma, 17% of which had elevated IOP which was secondary to iris neovascularization in 70% of cases and to an angle closure without neovascularization in 27%. Several other intraocular tumors including lymphoma, leukemia, medulloepithelioma, melanocytoma, and adenoma of the iris pigment epithelium were occasionally associated with secondary elevated IOP.