24-Hour IOP Telemetry in the Nonhuman Primate: Implant System Performance and Initial Characterization of IOP at Multiple Timescales

Downs, J. Crawford; Burgoyne, Claude F.; Seigfreid, William P.; Reynaud, Juan; Strouthidis, Nicholas G.; Sallee, Verney L.

doi:10.1167/iovs.11-7955

Cited by 122 publications

(135 citation statements)

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“…We have found this to be true across a range of frequencies, which are present in the dynamic forces the eye experiences regularly during physiologic disturbances, such as ocular pulse, blinking, ocular movements, posture change, and eye rubbing. Recent studies on humans 34 and rhesus monkeys 35 reported data upon long-term monitoring of IOP showing frequent and quick IOP fluctuations. Based on our estimate using spectral analysis of the reported dynamic IOP curves obtained from rhesus monkeys, 35 the in vivo IOP could contain most of the frequencies tested in our study.…”

Section: Discussionmentioning

confidence: 99%

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Biomechanical Properties and Correlation With Collagen Solubility Profile in the Posterior Sclera of Canine Eyes With anADAMTS10Mutation

Palko

Iwabe

Pan

et al. 2013

Invest. Ophthalmol. Vis. Sci.

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Citation: Palko JR, Iwabe S, Pan X, Agarwal G, Komáromy AM, Liu J. Biomechanical properties and correlation with collagen solubility profile in the posterior sclera of canine eyes with an ADAMTS10 mutation. Invest Ophthalmol Vis Sci. 2013;54:268554: -269554: . DOI:10.1167 PURPOSE. We examined the biomechanical properties and correlation with the collagen solubility profile of the posterior sclera in a canine model of primary open-angle glaucoma caused by the G661R missense mutation in the ADAMTS10 gene. METHODS.Scleral strips from ADAMTS10-mutant (affected) dogs and age-matched controls were collected. Viscoelastic properties (i.e., complex modulus and tan[d]) were measured using dynamic mechanical analysis (DMA) with a 0.15% sinusoidal strain at different frequencies superimposed upon different preloads. A tensile ramp was performed following DMA. The collagen solubility profile was examined using a colorimetric hydroxyproline assay to determine the amount of soluble and insoluble collagen. The viscoelastic properties were compared between groups using linear mixed models for repeated measures at different preloads and frequencies. The correlation between the biomechanical properties and collagen content were evaluated using Pearson correlations. RESULTS.Complex modulus and tan(d) were significantly lower in the affected group (P < 0.001), and the differences were consistent at different preloads and frequencies. The B value from the tensile ramp test also was significantly lower in the affected group (P ¼ 0.02). The insoluble collagen was significantly lower in the affected group (P < 0.05) and correlated positively with the complex modulus (R ¼ 0.88, P < 0.005).CONCLUSIONS. An inherently weaker and biochemically distinct posterior sclera was observed in dogs with the G661R missense mutation in ADAMTS10 before clinical indications of optic nerve damage. It remains to be shown whether and how the altered scleral biomechanics may affect the rate of glaucoma progression following intraocular pressure elevation.

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Section: Discussionmentioning

confidence: 99%

“…Recent studies on humans 34 and rhesus monkeys 35 reported data upon long-term monitoring of IOP showing frequent and quick IOP fluctuations. Based on our estimate using spectral analysis of the reported dynamic IOP curves obtained from rhesus monkeys, 35 the in vivo IOP could contain most of the frequencies tested in our study.…”

Section: Discussionmentioning

confidence: 99%

Biomechanical Properties and Correlation With Collagen Solubility Profile in the Posterior Sclera of Canine Eyes With anADAMTS10Mutation

Palko

Iwabe

Pan

et al. 2013

Invest. Ophthalmol. Vis. Sci.

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“…Where possible, we chose to maintain the old EG eyes at higher IOPs than the young EG eyes, so as to achieve a bias toward more rather than less deformation in the old EG eyes. Our IOP data suggest we achieved this bias, although measurements were made only weekly, whereas continuous telemetric IOP characterization 48 would have been necessary to most accurately quantify IOP insult.…”

Section: Figurementioning

confidence: 94%

Age-Related Differences in Longitudinal Structural Change by Spectral-Domain Optical Coherence Tomography in Early Experimental Glaucoma

Yang

Gardiner

et al. 2014

Invest. Ophthalmol. Vis. Sci.

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Citation: Yang H, He L, Gardiner SK, et al. Age-related differences in longitudinal structural change by spectraldomain optical coherence tomography in early experimental glaucoma. Invest Ophthalmol Vis Sci. 2014;55:6409-6420 DOI:10.1167/ iovs.14-14156 PURPOSE. To characterize age-related differences in the magnitude of spectral-domain optical coherence tomography (SD-OCT) structural change in early experimental glaucoma (EG).METHODS. Both eyes from four young (1.4-2.6 years) and four old (18.6-21.9 years) rhesus monkeys were imaged at least three times at baseline, and then every 2 weeks after laserinduced, chronic, unilateral IOP elevation until the onset of EG (confocal scanning laser tomographic surface change confirmed twice). Two to 20 weeks after EG onset, animals were euthanized and optic nerve axon counts for all eyes were performed. Masked operators delineated retinal and ONH landmarks in 40 radial B-scans from each eye and imaging session to quantify change from baseline in five SD-OCT neural and connective tissue parameters. The effects of EG, age, and EG 3 age interactions on the magnitude, rate (magnitude per postlaser time), and IOP responsiveness (magnitude per cumulative IOP insult) of postlaser parameter change were individually assessed using general estimating equation models.RESULTS. Presac SD-OCT RNFLT and minimum rim width change and postmortem axon loss was not significantly different in old compared with young EG eyes. The rate of change and IOP responsiveness of the parameters anterior lamina cribrosa surface depth relative to Bruch's membrane opening (BMO) and BMO depth relative to peripheral Bruch's membrane were significantly lower (P < 0.05) in the old compared with the young EG eyes.CONCLUSIONS. At similar postlaser times, levels of cumulative IOP insult and axonal damage, SD-OCT-detected ONH connective tissue structural change is greater in young compared with old monkey EG eyes.

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“…In addition to the CLS, other non-invasive devices are currently being developed (14,15) . In 2011, an implantable telemetric pressure transducer system to continuously monitor IOP was tested in non-human primates and shown to provide accurate measurements (16) . For the moment, however, the extensive surgery required for its implantation precludes use in humans.…”

Section: Glaucoma a Doença Que Nunca Dormementioning

confidence: 99%

Glaucoma, the disease that never sleeps

Mansouri¹

2016

Revista Brasileira De Oftalmologia

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6Rev Bras Oftalmol. 2016; 75 (1): 5-6 Mansouri K Once such devices become available for routine clinical use, it will become obvious that we lack true understanding of the relationship between IOP and glaucoma:· Does nocturnal IOP have the same impact on glaucoma as diurnal IOP? · Which IOP parameters are most relevant to glaucoma: mean, peak, short or long-term variability? · Are there specific circadian IOP patterns that are related to glaucoma development and may predict its future progression?It is likely that the use of 24-h IOP monitoring will improve understanding and management of glaucoma. Ultimately, clinically-driven 24-h IOP data may lead to chrono-therapeutic delivery of glaucoma medications instead of the current practice of standard scheduling of drop instillation. In the meantime, clinicians are encouraged to obtain as many daily (and nightly) IOP measurements, possibly augmented with provocative testing, such as water loading, as possible to gain a better understanding of a patient's IOP dynamics and to personalize his treatment.

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24-Hour IOP Telemetry in the Nonhuman Primate: Implant System Performance and Initial Characterization of IOP at Multiple Timescales

Cited by 122 publications

References 44 publications

Biomechanical Properties and Correlation With Collagen Solubility Profile in the Posterior Sclera of Canine Eyes With anADAMTS10Mutation

Biomechanical Properties and Correlation With Collagen Solubility Profile in the Posterior Sclera of Canine Eyes With anADAMTS10Mutation

Age-Related Differences in Longitudinal Structural Change by Spectral-Domain Optical Coherence Tomography in Early Experimental Glaucoma

Glaucoma, the disease that never sleeps

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