Ocular Rigidity, Outflow Facility, Ocular Pulse Amplitude, and Pulsatile Ocular Blood Flow in Open-Angle Glaucoma: A Manometric Study

Dastiridou, Anna; Tsironi, Evangelia E.; Tsilimbaris, Miltiadis K.; Ginis, Harilaos; Karyotakis, Nikos; Cholevas, Pierros; Androudi, Sofia; Pallikaris, Ioannis G.

doi:10.1167/iovs.13-12303

Cited by 36 publications

(46 citation statements)

References 46 publications

(61 reference statements)

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“…In the article in question, 1 the calculated values of the sensitivity of outflow resistance to IOP (Q and a 1 ) differ markedly from previously published results.…”

contrasting

confidence: 76%

“…Therefore, it would be of interest to show an x-y scatter plot of the values of C at the two pressure levels plotted against each other for each eye in both groups. The results, 1 however, indicate that the outflow pathway is extremely sensitive to high IOPs under cycloplegia, presumably as result of partial collapse of Schlemm's canal. 5 …”

mentioning

confidence: 66%

“…I read with great interest the recent paper of Dastiridou et al 1 In their paper, the dependence of outflow facility (C) on IOP (P) was reported for healthy and glaucomatous, anaesthetized, cycloplegic human eyes.…”

mentioning

confidence: 99%

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Dependence of Outflow Facility on Intraocular Pressure?

Jensen

2014

Invest. Ophthalmol. Vis. Sci.

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“…In the article in question, 1 the calculated values of the sensitivity of outflow resistance to IOP (Q and a 1 ) differ markedly from previously published results.…”

contrasting

confidence: 76%

mentioning

confidence: 66%

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Dependence of Outflow Facility on Intraocular Pressure?

Jensen

2014

Invest. Ophthalmol. Vis. Sci.

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“…Other than the method of the OR coefficient of Friedenwald [54], other authors have proposed equations that include anterior chamber manometry, AL changes, measurement of pulse amplitude and fundus vessel pulsations, ultrasound elastography, and evaluation of corneal hysteresis [52]. However, there are some drawbacks for most of these methodologies, such as poor accuracy or reproducibility, technical complexity, and, above all, invasive measurement techniques [52,55,56]. Recently, Wang et al [49] used a noninvasive technique to estimate OR in vivo.…”

Section: Opa and Glaucomamentioning

confidence: 99%

Review on Dynamic Contour Tonometry and Ocular Pulse Amplitude

et al. 2015

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Intraocular pressure (IOP) measurement is the cornerstone of the management of glaucoma patients. The gold standard for assessing IOP is Goldmann applanation tonometry (GAT). Recently, the dynamic contour tonometer (DCT) has become available. While both devices provide reliable IOP measurements, the results are not interchangeable. DCT has the advantage of measuring an additional parameter: ocular pulse amplitude (OPA). OPA is defined as the difference between systolic and diastolic IOP and represents the pulsatile wave front produced by the varying amount of blood in the eye during the cardiac cycle. It has been shown to vary with ocular structural parameters, such as axial length, corneal thickness, and ocular rigidity, as well as with systemic variables like heart rate, blood pressure, and left ventricular ejection fraction. Although the existence of some of these associations is still controversial, the clinical relevance of OPA has been consistently suggested, especially in glaucoma. Further research on this intriguing parameter could not only provide insight into glaucoma pathophysiology but also help integrate this variable into clinical practice.

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“…Increased ocular rigidity affects other tissues as well, including ocular blood flow through the sclera and optic nerve. It has been correlated to the pathogenesis of macular degeneration (5) and other age-related eye diseases (6) . Ocular rigidity may not only impact the loss of visual accommodation but also have more extensive clinical significance.…”

mentioning

confidence: 99%

Restoration of accommodation: new perspectives

Swartz

Rocha

Jackson

et al. 2014

Arquivos Brasileiros De Oftalmologia

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Presbyopia is the loss of accommodative ability that occurs with age. Current accommodative theory postulates that the lens is primarily responsible for the refractive change that allows us to read. Our understanding of this process has grown substantially with the advent of new technologies, including ultrasound biomicroscopy (UBM), endoscopy, optical coherence tomography (OCT), ray-tracing and wavefront analysis. Goldberg's Postulate incorporates all elements of the zonular apparatus into the phenomenon of accommodation (1) . The ciliary body contracts during accommodation. Biometry has shown that the lens thickness increases and the anterior chamber depth decreases (2) . It has also demonstrated the lens capsule steepens, as the posterior-lens surface moves backwards (2) . In addition, there is a decrease in the distance from scleral spur to the ora serrata. UBM identified an attachment zone of the posterior zonules adjacent to the ora, and contraction of these zonules is thought to be the etiology of the decrease in distance found with accommodation. This complex action of the zonules is suspected to be reciprocal. As the same time the anterior zonules relax, reducing their tension on the lens such that the lens changes shape anteriorly, the posterior zonules contract, moving the posterior capsule backward. This vitreal-zonular complex stiffens with age, losing its elasticity (1)(2)(3) . The age-related changes in these structures and their biomechanical interactions with the ciliary-lens complex may contribute to presbyopia (3). It has been newly discovered that there are also changes in extralenticular structures which may have an impact on the loss of accommodation which were previously deemed to be of very little importance, namely the sclera and choroid (2) . All ocular tissues are made of collagen and are impacted like all other connective tissues by age. Ocular rigidity has been correlated with age (4) and the sclera undergoes scleral sclerosis as well as metabolic physiological stress. With the loss of elasticity, the more rigid sclera elicits compression and loading stresses upon underlying structures, specifically those related to accommodative function. Increased ocular rigidity affects other tissues as well, including ocular blood flow through the sclera and optic nerve. It has been correlated to the pathogenesis of macular degeneration (5) and other age-related eye diseases (6) . Ocular rigidity may not only impact the loss of visual accommodation but also have more extensive clinical significance.The impact of age on the lenticular-based model of loss of accommodation is well documented. The amount of accommodation lost with age related to extralenticular apparatus (primarily the zonules, choroid, and sclera) was only recently investigated (7) . It is also now known that the sclera becomes less deformable during accommodation in the nasal area with age (2) . New models suggest up to 2 diopters that might be contributed by ex tralenticular structures (7) . To date, there has been at least up to ...

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Ocular Rigidity, Outflow Facility, Ocular Pulse Amplitude, and Pulsatile Ocular Blood Flow in Open-Angle Glaucoma: A Manometric Study

Cited by 36 publications

References 46 publications

Dependence of Outflow Facility on Intraocular Pressure?

Dependence of Outflow Facility on Intraocular Pressure?

Review on Dynamic Contour Tonometry and Ocular Pulse Amplitude

Restoration of accommodation: new perspectives

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