Optic nerve head and intraocular pressure in the guinea pig eye

Ostrin, Lisa A; Wildsoet, Christine F.

doi:10.1016/j.exer.2015.12.007

Cited by 36 publications

(31 citation statements)

References 74 publications

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“…However, presence of a distinct, collagenous lamina cribrosa in guinea pigs has been reported in a previous study using histological approaches. 17 …”

Section: Discussionmentioning

confidence: 99%

“…Guinea pig retinal physiology, both in vitro single cell recordings 13, 14 and in vivo electrophysiology, 15, 16 have previously been characterized. Additionally, in vitro retinal and optic nerve head (ONH) structures in the guinea pig have been examined; 17, 18 however, in vivo methods to assess the retina, choroid and ONH have not yet been established.…”

Section: Introductionmentioning

confidence: 99%

“…36, 37 Structural changes in the lamina cribrosa have been described in glaucomatous eyes in a number of previous studies. 8, 38, 39 Unlike rats and mice, guinea pigs possess a collagenous lamina cribrosa, 17 which may be better suited to model glaucomatous change observed at the ONH in humans. Additionally, guinea pigs do not require anesthesia for intraocular pressure measurements; therefore anesthesia induced alterations in intraocular pressure can be avoided.…”

Section: Introductionmentioning

confidence: 99%

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In Vivo Imaging of the Retina, Choroid, and Optic Nerve Head in Guinea Pigs

Jnawali

Beach

Ostrin

2018

Current Eye Research

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Purpose Guinea pigs are increasingly being used as a model of myopia, and may also represent a novel model of glaucoma. Here, optical coherence tomography (OCT) imaging was performed in guinea pigs. In vivo measurements of retinal, choroidal and optic nerve head parameters were compared with histology, and repeatability and interocular variations were assessed. Methods OCT imaging and histology were performed on adult guinea pigs (n = 9). Using a custom program in Matlab, total retina, ganglion cell/nerve fiber layer (GC/NFL), outer retina and choroid thicknesses were determined. Additionally, Bruch’s membrane opening (BMO) area and diameter, and minimum rim width were calculated. Intraobserver, interocular and intersession coefficients of variation (CV) and intraclass correlation coefficients (ICC) were assessed. Results Retina, GC/NFL, outer retina and choroid thicknesses from in vivo OCT imaging were 147.7 ± 5.8 μm, 59.2 ± 4.5 μm, 72.4 ± 2.4 μm, and 64.8 ± 11.6 μm, respectively. Interocular CV ranged from 1.8 to 11% (paired t-test, p = 0.16 to 0.81), and intersession CV ranged from 1.1 to 5.6% (p = 0.12 to 0.82), with the choroid showing the greatest variability. BMO area was 0.192 ± 0.023 mm2, and diameter was 493.79 ± 31.89, with intersession CV of 3.3% and 1.7%, respectively. Hyper reflective retinal layers in OCT correlated with plexiform and RPE layers in histology. Conclusion In vivo OCT imaging and quantification of guinea pig retina and optic nerve head parameters were repeatable and similar between eyes of the same animal. In vivo visibility of retinal cell layers correlated well with histological images.

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“…However, presence of a distinct, collagenous lamina cribrosa in guinea pigs has been reported in a previous study using histological approaches. 17 …”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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In Vivo Imaging of the Retina, Choroid, and Optic Nerve Head in Guinea Pigs

Jnawali

Beach

Ostrin

2018

Current Eye Research

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“…Another advantage was our use of a non-human primate model, which is generally recognized to be the model closest to humans 25 . Many previous studies of IOP or ICP effects have been done in non-primate models, such as dog, rat, or pig 3,26–28 . This is particularly problematic for animal models that do not have a collagenous lamina cribrosa, and which may therefore not have the same biomechanical response to variations in pressure.…”

Section: Discussionmentioning

confidence: 99%

Mapping in-vivo optic nerve head strains caused by intraocular and intracranial pressures

et al. 2017

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Although it is well documented that abnormal levels of either intraocular (IOP) or intracranial pressure (ICP) can lead to potentially blinding conditions, such as glaucoma and papilledema, little is known about how the pressures actually affect the eye. Even less is known about potential interplay between their effects, namely how the level of one pressure might alter the effects of the other. Our goal was to measure in-vivo the pressure-induced stretch and compression of the lamina cribrosa due to acute changes of IOP and ICP. The lamina cribrosa is a structure within the optic nerve head, in the back of the eye. It is important because it is in the lamina cribrosa that the pressure-induced deformations are believed to initiate damage to neural tissues leading to blindness. An eye of a rhesus macaque monkey was imaged in-vivo with optical coherence tomography while IOP and ICP were controlled through cannulas in the anterior chamber and lateral ventricle, respectively. The image volumes were analyzed with a newly developed digital image correlation technique. The effects of both pressures were highly localized, nonlinear and non-monotonic, with strong interactions. Pressure variations from the baseline normal levels caused substantial stretch and compression of the neural tissues in the posterior pole, sometimes exceeding 20%. Chronic exposure to such high levels of biomechanical insult would likely lead to neural tissue damage and loss of vision. Our results demonstrate the power of digital image correlation technique based on non-invasive imaging technologies to help understand how pressures induce biomechanical insults and lead to vision problems.

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“…Colonies of cats and dogs with hereditary glaucoma are available (Grozdanic et al, 2010; Kuchtey et al, 2011; Narfstrom et al, 2013). The ONH of the guinea pig has laminar beams that are radially oriented, emanating from a central fibrovascular stalk (Morrison et al, 1995; Ostrin and Wildsoet, 2016). The guinea pig retina is avascular (De Schaepdrijver et al, 1989), which is a substantial difference to the human.…”

Section: Animal Models Of Glaucomamentioning

confidence: 99%

Biomechanical aspects of axonal damage in glaucoma: A brief review

Tamm

Ethier

Dowling

et al. 2017

Experimental Eye Research

100

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The biomechanical environment within the optic nerve head (ONH) is complex and is likely directly involved in the loss of retinal ganglion cells (RGCs) in glaucoma. Unfortunately, our understanding of this process is poor. Here we describe factors that influence ONH biomechanics, including ONH connective tissue microarchitecture and anatomy; intraocular pressure (IOP); and cerebrospinal fluid pressure (CSFp). We note that connective tissue factors can vary significantly from one individual to the next, as well as regionally within an eye, and that the understanding of ONH biomechanics is hindered by anatomical differences between small-animal models of glaucoma (rats and mice) and humans. Other challenges of using animal models of glaucoma to study the role of biomechanics include the complexity of assessing the degree of glaucomatous progression; and inadequate tools for monitoring and consistently elevating IOP in animal models. We conclude with a consideration of important open research questions/challenges in this area, including: (i) Creating a systems biology description of the ONH; (ii) addressing the role of astrocyte connective tissue remodeling and reactivity in glaucoma; (iii) providing a better characterization of ONH astrocytes and non-astrocytic constituent cells; (iv) better understanding the role of ONH astrocyte phagocytosis, proliferation and death; (v) collecting gene expression and phenotype data on a larger, more coordinated scale; and (vi) developing an implantable IOP sensor.

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Optic nerve head and intraocular pressure in the guinea pig eye

Cited by 36 publications

References 74 publications

In Vivo Imaging of the Retina, Choroid, and Optic Nerve Head in Guinea Pigs

In Vivo Imaging of the Retina, Choroid, and Optic Nerve Head in Guinea Pigs

Mapping in-vivo optic nerve head strains caused by intraocular and intracranial pressures

Biomechanical aspects of axonal damage in glaucoma: A brief review

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