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Jonas JB, Jonas RA, Jonas SB, Panda-Jonas S. Bruch's membrane and Brücke's muscle in the pars plana region. Acta Ophthalmol 2024; 102:e53-e59. [PMID: 38185862 DOI: 10.1111/aos.15678] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/13/2023] [Indexed: 01/09/2024]
Abstract
PURPOSE To examine Bruch's membrane (BM) in association with the longitudinal part of the ciliary muscle (LPCM) in the pars plana region. METHODS Using light microscopy, we histomorphometrically assessed BM and the LPCM in the pars plana region. RESULTS The histomorphometric study included 51 eyes (51 patients; mean age: 60.8 ± 15.0 years; axial length: 26.0 ± 3.3 mm; range: 21.0-36.0 mm). The LPCM (total length: 4.60 ± 1.10 mm) ended 1.15 ± 0.56 mm anterior to the ora serrata. Within the pars plana region, the LPCM (length: 2.58 ± 0.98 mm) had direct contact with BM for 1.95 ± 0.99 mm (71.1 ± 18.4% of the BM undersurface), while a capillary layer was interposed between the BM and the LPCM for 0.70 ± 0.40 mm (29.0 ± 18.4%). In the pars plana region free of LPCM close to the ora serrata, the percentage of BM covered by the capillary layer was higher than in the pars plana region containing the LPCM (63.0 ± 42.1% vs. 29.0 ± 18.4%; p < 0.001). At the LPCM end, BM was in direct contact with a collagenous tissue from the LPCM and was focally thickened as compared to BM with an underlying capillary layer (9.5 ± 5.3 μm vs. 4.3 ± 1.2 μm; p < 0.001). CONCLUSIONS The direct contact of BM with the LPCM in the pars plana in association with focal BM thickening at the LPCM end suggests an insertion of LPCM on the BM. Taking into account the biomechanical strength of BM, it may imply a functional unit of the LPCM with BM in the process of accommodation with a secondary movement of the posterior BM and tertiary thickening of the subfoveal choroidal space.
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Affiliation(s)
- Jost B Jonas
- Department of Ophthalmology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
- Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Rahul A Jonas
- Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Shefali B Jonas
- Privatpraxis Prof Jonas und Dr Panda-Jonas, Heidelberg, Germany
| | - Songhomitra Panda-Jonas
- Department of Ophthalmology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
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Johnstone M, Xin C, Martin E, Wang R. Trabecular Meshwork Movement Controls Distal Valves and Chambers: New Glaucoma Medical and Surgical Targets. J Clin Med 2023; 12:6599. [PMID: 37892736 PMCID: PMC10607137 DOI: 10.3390/jcm12206599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/09/2023] [Accepted: 08/30/2023] [Indexed: 10/29/2023] Open
Abstract
Herein, we provide evidence that human regulation of aqueous outflow is by a pump-conduit system similar to that of the lymphatics. Direct observation documents pulsatile aqueous flow into Schlemm's canal and from the canal into collector channels, intrascleral channels, aqueous veins, and episcleral veins. Pulsatile flow in vessels requires a driving force, a chamber with mobile walls and valves. We demonstrate that the trabecular meshwork acts as a deformable, mobile wall of a chamber: Schlemm's canal. A tight linkage between the driving force of intraocular pressure and meshwork deformation causes tissue responses in milliseconds. The link provides a sensory-motor baroreceptor-like function, providing maintenance of a homeostatic setpoint. The ocular pulse causes meshwork motion oscillations around the setpoint. We document valves entering and exiting the canal using real-time direct observation with a microscope and multiple additional modalities. Our laboratory-based high-resolution SD-OCT platform quantifies valve lumen opening and closing within milliseconds synchronously with meshwork motion; meshwork tissue stiffens, and movement slows in glaucoma tissue. Our novel PhS-OCT system measures nanometer-level motion synchronous with the ocular pulse in human subjects. Movement decreases in glaucoma patients. Our model is robust because it anchors laboratory studies to direct observation of physical reality in humans with glaucoma.
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Affiliation(s)
- Murray Johnstone
- Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA;
| | - Chen Xin
- Beijing Tongren Eye Center, Beijing Institute of Ophthalmology, Beijing 100730, China
- Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
| | - Elizabeth Martin
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Ruikang Wang
- Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA;
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
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3
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Paduca A, Lundmark PO, Bruenech JR. Does Surgical Resection of Horizontal Extraocular Muscles Disrupt Ocular Proprioceptors? Clin Ophthalmol 2023; 17:1395-1405. [PMID: 37214153 PMCID: PMC10198280 DOI: 10.2147/opth.s381247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 04/06/2023] [Indexed: 05/24/2023] Open
Abstract
Purpose It has been promoted that disturbance of ocular proprioception may play a role in the pathogenesis of concomitant strabismus and other types of oculomotor anomalies. The aim of the study was to obtain knowledge about how surgical foreshortening of the myotendinous region potentially affects the proprioceptors that resides in this area of the muscles and to test the hypothesis that avoiding disruption of ocular proprioceptors result in a more favorable long term postoperative result. Patients and Methods The distal end of the lateral and medial rectus muscles from patients with manifest concomitant strabismus with a deviation of ≥15 prism diopters (PD) were collected during strabismus surgery and processed for light microscopy by standard histochemical techniques. Histological analysis served to differentiate between the tissue samples containing pure tendon, versus samples containing the myotendinous junction. Criteria for successful outcome was defined as a residual angle of deviation less than 10 PD. The binocular status of the patient was measured pre- and post-operatively at 6-months of follow-up. Results Tissue samples from 43 patients (median age 19 years old, range 3-58 years) were collected during surgery. Twenty-six of the samples contained pure tendon, while 17 contained muscle fibres. The evolution of the post-operative result revealed a moderate reduction in the residual angle of deviation in patient-samples containing pure tendon. In contrast, the residual angle of deviation clearly increased in patient-samples containing muscle fibres. The difference between the two groups reached statistical significance after 6 months. Successful outcome was found to be more than three times more likely in cases where surgery was performed in pure tendon, compared to muscle fibres. Conclusion The current study supports the hypothesis that avoiding disruption of ocular proprioceptors, located in the distal myotendinous region, results in a more favorable postoperative result.
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Affiliation(s)
- Ala Paduca
- Ophthalmology Department, State University of Medicine and Pharmacy Nicolae Testemitanu, Chisinau, Republic of Moldova
| | - Per O Lundmark
- Department of Optometry, Radiography and Lighting Design, Faculty of Health and Social Sciences, University of South-Eastern Norway, Kongsberg, Norway
| | - J Richard Bruenech
- Department of Optometry, Radiography and Lighting Design, Faculty of Health and Social Sciences, University of South-Eastern Norway, Kongsberg, Norway
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4
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Croft MA, Peterson J, Smith C, Kiland J, Nork TM, Mcdonald JP, Katz A, Hetzel S, Lütjen-Drecoll E, Kaufman PL. Accommodative movements of the choroid in the optic nerve head region of human eyes, and their relationship to the lens. Exp Eye Res 2022; 222:109124. [PMID: 35688214 PMCID: PMC9783760 DOI: 10.1016/j.exer.2022.109124] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 04/30/2022] [Accepted: 05/18/2022] [Indexed: 12/27/2022]
Abstract
The ciliary muscle (CM) powers the accommodative response, and during accommodation the CM pulls the choroid forward in the region of the ora serrata. Our goal was to elucidate the accommodative movements of the choroid in the optic nerve region in humans and to determine whether these movements are related to changes in the lens dimensions that occur with aging, in the unaccommodated and accommodated state. Both eyes of 12 human subjects (aged 18-51 yrs) were studied. Homatropine (1 drop/5%) was used to relax the ciliary muscle (unaccommodated or "resting" eye) and pilocarpine was used to induce the maximum accommodative response (2 drops/4%) (accommodated eye). Images of the fundus and choroid were collected in the region of the optic nerve (ON) via Spectralis OCT (infrared and EDI mode), and choroidal thickness was determined. Ultrasound biomicroscopy (UBM; 50 MHz, 35 MHz) images were collected in the region of the lens/capsule and ciliary body. OCT and UBM images were collected in the resting and accommodated state. The unaccommodated choroidal thickness declined significantly with age (p = 0.0073, r = 0.73) over the entire age range of the subjects studied (18-51 years old). The choroidal thickness was significantly negatively correlated with lens thickness in the accommodated (p = 0.01) and the unaccommodated states (p = 0.005); the thicker the lens the thinner the choroid. Choroid movements around the optic nerve during accommodation were statistically significant; during accommodation the choroid both thinned and moved centrifugally (outward/away from the optic nerve head). The accommodative choroid movements did not decline significantly with age and were not correlated with accommodative amplitude. Measurement of the choroidal thickness is possible with the Spectralis OCT instrument using EDI mode and can be used to determine the accommodative changes in choroidal thickness. The choroidal thickness decreased with age and during accommodation. It may be that age-related choroidal thinning is due to changes in the geometry of the accommodative apparatus to which it is attached (i.e., ciliary muscle/lens complex) such that when the lens is thicker, the choroid is thinner. Accommodative decrease in choroidal thickness and stretch of the retina/choroid may indicate stress/strain forces in the region of the optic nerve during accommodation and may have implications for glaucoma.
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Affiliation(s)
- Mary Ann Croft
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53792, USA.
| | - John Peterson
- Diagnostic Imaging Services Lead, UCSF Health, Wayne and Gladys Valley Center for Vision, 490 Illinois St., San Francisco, CA, 94158, USA
| | - Christopher Smith
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53792, USA
| | - Julie Kiland
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53792, USA
| | - T Michael Nork
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53792, USA
| | - Jared P Mcdonald
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53792, USA
| | - Alexander Katz
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53792, USA
| | - Scott Hetzel
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, USA
| | | | - Paul L Kaufman
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53792, USA; Wisconsin National Primate Research Center, USA
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Johnstone M, Xin C, Tan J, Martin E, Wen J, Wang RK. Aqueous outflow regulation - 21st century concepts. Prog Retin Eye Res 2021; 83:100917. [PMID: 33217556 PMCID: PMC8126645 DOI: 10.1016/j.preteyeres.2020.100917] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/24/2022]
Abstract
We propose an integrated model of aqueous outflow control that employs a pump-conduit system in this article. Our model exploits accepted physiologic regulatory mechanisms such as those of the arterial, venous, and lymphatic systems. Here, we also provide a framework for developing novel diagnostic and therapeutic strategies to improve glaucoma patient care. In the model, the trabecular meshwork distends and recoils in response to continuous physiologic IOP transients like the ocular pulse, blinking, and eye movement. The elasticity of the trabecular meshwork determines cyclic volume changes in Schlemm's canal (SC). Tube-like SC inlet valves provide aqueous entry into the canal, and outlet valve leaflets at collector channels control aqueous exit from SC. Connections between the pressure-sensing trabecular meshwork and the outlet valve leaflets dynamically control flow from SC. Normal function requires regulation of the trabecular meshwork properties that determine distention and recoil. The aqueous pump-conduit provides short-term pressure control by varying stroke volume in response to pressure changes. Modulating TM constituents that regulate stroke volume provides long-term control. The aqueous outflow pump fails in glaucoma due to the loss of trabecular tissue elastance, as well as alterations in ciliary body tension. These processes lead to SC wall apposition and loss of motion. Visible evidence of pump failure includes a lack of pulsatile aqueous discharge into aqueous veins and reduced ability to reflux blood into SC. These alterations in the functional properties are challenging to monitor clinically. Phase-sensitive OCT now permits noninvasive, quantitative measurement of pulse-dependent TM motion in humans. This proposed conceptual model and related techniques offer a novel framework for understanding mechanisms, improving management, and development of therapeutic options for glaucoma.
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Affiliation(s)
| | - Chen Xin
- Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, China.
| | - James Tan
- Doheny Eye Institute and UCLA Department of Ophthalmology, USA.
| | | | | | - Ruikang K Wang
- Department of Ophthalmology, University of Washington, USA; Department of Bioengineering, University of Washington, USA.
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van Zyl T, Yan W, McAdams A, Peng YR, Shekhar K, Regev A, Juric D, Sanes JR. Cell atlas of aqueous humor outflow pathways in eyes of humans and four model species provides insight into glaucoma pathogenesis. Proc Natl Acad Sci U S A 2020; 117:10339-10349. [PMID: 32341164 PMCID: PMC7229661 DOI: 10.1073/pnas.2001250117] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Increased intraocular pressure (IOP) represents a major risk factor for glaucoma, a prevalent eye disease characterized by death of retinal ganglion cells; lowering IOP is the only proven treatment strategy to delay disease progression. The main determinant of IOP is the equilibrium between production and drainage of aqueous humor, with compromised drainage generally viewed as the primary contributor to dangerous IOP elevations. Drainage occurs through two pathways in the anterior segment of the eye called conventional and uveoscleral. To gain insights into the cell types that comprise these pathways, we used high-throughput single-cell RNA sequencing (scRNAseq). From ∼24,000 single-cell transcriptomes, we identified 19 cell types with molecular markers for each and used histological methods to localize each type. We then performed similar analyses on four organisms used for experimental studies of IOP dynamics and glaucoma: cynomolgus macaque (Macaca fascicularis), rhesus macaque (Macaca mulatta), pig (Sus scrofa), and mouse (Mus musculus). Many human cell types had counterparts in these models, but differences in cell types and gene expression were evident. Finally, we identified the cell types that express genes implicated in glaucoma in all five species. Together, our results provide foundations for investigating the pathogenesis of glaucoma and for using model systems to assess mechanisms and potential interventions.
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Affiliation(s)
- Tavé van Zyl
- Department of Ophthalmology, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA 02114;
- Center for Brain Science, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Wenjun Yan
- Center for Brain Science, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Alexi McAdams
- Department of Ophthalmology, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA 02114
- Center for Brain Science, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Yi-Rong Peng
- Center for Brain Science, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Karthik Shekhar
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142
- Koch Institute of Integrative Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Aviv Regev
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142
- Koch Institute of Integrative Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
- Klarman Cell Observatory, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142
| | - Dejan Juric
- Department of Medicine, Harvard Medical School and Massachusetts General Hospital Cancer Center, Boston, MA 02114
| | - Joshua R Sanes
- Center for Brain Science, Harvard University, Cambridge, MA 02138;
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
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Kaufman PL, Lütjen Drecoll E, Croft MA. Presbyopia and Glaucoma: Two Diseases, One Pathophysiology? The 2017 Friedenwald Lecture. Invest Ophthalmol Vis Sci 2019; 60:1801-1812. [PMID: 31038661 PMCID: PMC6540935 DOI: 10.1167/iovs.19-26899] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Paul L Kaufman
- Department of Ophthalmology and Visual Sciences, Wisconsin National Primate Research Center, McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | | | - Mary Ann Croft
- Department of Ophthalmology and Visual Sciences, Wisconsin National Primate Research Center, McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States
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Vienne C, Plantier J, Neveu P, Priot AE. (Disparity-Driven) Accommodation Response Contributes to Perceived Depth. Front Neurosci 2018; 12:973. [PMID: 30618592 PMCID: PMC6305428 DOI: 10.3389/fnins.2018.00973] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/05/2018] [Indexed: 11/23/2022] Open
Abstract
When looking at objects at various distances in the physical space, the accommodation and vergence systems adjust their parameters to provide a single and clear vision of the world. Subtended muscle activity provides oculomotor cues that can contribute to the perception of depth and distance. While several studies have outlined the role of vergence in distance perception, little is known about the contribution of its concommitant accommodation component. It is possible to unravel the role of each of these physiological systems by placing observers in a situation where there is a conflict between accommodation and vergence distances. We thus sought to determine the contribution of each response system to perceived depth by simultaneously measuring vergence and accommodation while participants judged the depth of 3D stimuli. The distance conflict decreased depth constancy for stimulus displayed with negative disparity steps (divergence). Although vergence was unaffected by the stimulus distance, accommodation responses were significantly reduced when the stimulus was displayed with negative disparities. Our results show that biases in perceived depth follow undershoots in the disparity-driven accommodation response. These findings suggest that accommodation responses (i.e., from oculomotor information) can contribute to perceived depth.
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Affiliation(s)
- Cyril Vienne
- Institut de Recherche Biomédicale des Armées, Bretigny sur Orge, France
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Dimensions of the ciliary muscles of Brücke, Müller and Iwanoff and their associations with axial length and glaucoma. Graefes Arch Clin Exp Ophthalmol 2018; 256:2165-2171. [DOI: 10.1007/s00417-018-4085-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 07/10/2018] [Accepted: 07/26/2018] [Indexed: 10/28/2022] Open
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Lienbacher K, Ono S, Fleuriet J, Mustari M, Horn AKE. A Subset of Palisade Endings Only in the Medial and Inferior Rectus Muscle in Monkey Contain Calretinin. Invest Ophthalmol Vis Sci 2018; 59:2944-2954. [PMID: 30025142 PMCID: PMC5989861 DOI: 10.1167/iovs.18-24322] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 05/06/2018] [Indexed: 12/11/2022] Open
Abstract
Purpose To further chemically characterize palisade endings in extraocular muscles in rhesus monkeys. Methods Extraocular muscles of three rhesus monkeys were studied for expression of the calcium-binding protein calretinin (CR) in palisade endings and multiple endings. The complete innervation was visualized with antibodies against the synaptosomal-associated protein of 25 kDa and combined with immunofluorescence for CR. Six rhesus monkeys received tracer injections of choleratoxin subunit B or wheat germ agglutinin into either the belly or distal myotendinous junction of the medial or inferior rectus muscle to allow retrograde tracing in the C-group of the oculomotor nucleus. Double-immunofluorescence methods were used to study the CR content in retrogradely labeled neurons in the C-group. Results A subgroup of palisade and multiple endings was found to express CR, only in the medial and inferior rectus muscle. In contrast, the en plaque endings lacked CR. Accordingly, within the tracer-labeled neurons of the C-group, a subgroup expressed CR. Conclusions The study indicates that two different neuron populations targeting nontwitch muscle fibers are present within the C-group for inferior rectus and medial rectus, respectively, one expressing CR, one lacking CR. It is possible that the CR-negative neurons represent the basic population for all extraocular muscles, whereas the CR-positive neurons giving rise to CR-positive palisade endings represent a specialized, perhaps more excitable type of nerve ending in the medial and inferior rectus muscles, being more active in vergence. The malfunction of this CR-positive population of neurons that target nontwitch muscle fibers could play a significant role in strabismus.
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Affiliation(s)
- Karoline Lienbacher
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität, Munich, Germany
- German Center for Vertigo and Balance Disorders, Klinikum Grosshadern, Ludwig-Maximilians Universität, Munich, Germany
| | - Seiji Ono
- Faculty of Health and Sport Science, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Jérome Fleuriet
- Washington National Primate Research Center, Seattle, Washington, United States
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Michael Mustari
- Washington National Primate Research Center, Seattle, Washington, United States
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Anja K. E. Horn
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-Universität, Munich, Germany
- German Center for Vertigo and Balance Disorders, Klinikum Grosshadern, Ludwig-Maximilians Universität, Munich, Germany
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11
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Croft MA, Lütjen-Drecoll E, Kaufman PL. Age-related posterior ciliary muscle restriction - A link between trabecular meshwork and optic nerve head pathophysiology. Exp Eye Res 2017; 158:187-189. [PMID: 27453343 PMCID: PMC5253323 DOI: 10.1016/j.exer.2016.07.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 07/12/2016] [Accepted: 07/13/2016] [Indexed: 01/24/2023]
Abstract
The ciliary muscle plays a major role in controlling both accommodation and outflow facility in primates. The ciliary muscle and the choroid functionally form an elastic network that extends from the trabecular meshwork all the way to the back of the eye and ultimately attaches to the elastic fiber ring that surrounds the optic nerve and to the lamina cribrosa through which the nerve passes. The ciliary muscle governs the accommodative movement of the elastic network. With age ciliary muscle mobility is restricted by progressively inelastic posterior attachments and the posterior restriction makes the contraction progressively isometric; placing increased tension on the optic nerve region. In addition, outflow facility also declines with age and limbal corneoscleral contour bows inward. Age-related loss in muscle movement and altered limbal corneoscleral contour could both compromise the basal function of the trabecular meshwork. Further, recent studies in non-human primates show that the central vitreous moves posteriorly all the way back to the optic nerve region, suggesting a fluid current and a pressure gradient toward the optic nerve. Thus, there may be pressure and tension spikes on the optic nerve region during accommodation and these pressure and tension spikes may increase with age. This constellation of events could be relevant to glaucomatous optic neuropathy. In summary, our hypothesis is that glaucoma and presbyopia may be literally linked to each other, via the choroid, and that damage to the optic nerve may be inflicted by accommodative intraocular pressure and choroidal tension "spikes", which may increase with age.
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Affiliation(s)
- Mary Ann Croft
- Department of Ophthalmology & Visual Sciences, School of Medicine and Public Health, University of Wisconsin - Madison, USA.
| | | | - Paul L Kaufman
- Department of Ophthalmology & Visual Sciences, School of Medicine and Public Health, University of Wisconsin - Madison, USA
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12
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Flügel-Koch CM, Croft MA, Kaufman PL, Lütjen-Drecoll E. Anteriorly located zonular fibres as a tool for fine regulation in accommodation. Ophthalmic Physiol Opt 2015; 36:13-20. [PMID: 26490669 DOI: 10.1111/opo.12257] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 09/07/2015] [Indexed: 12/31/2022]
Abstract
PURPOSE To describe an anteriorly located system of zonular fibres that could be involved in fine-tuning of accommodation. METHODS Forty-six human and 28 rhesus monkey eyes were dissected and special preparations were processed for scanning electron microscopy and reflected-light microscopy. Additional series of frontal and sagittal histological and ultrathin sections were analysed in respect to the origin and insertion of anteriorly located zonules. The presence of sensory terminals at the site of the originating zonules within the connective tissue of the ciliary body was studied by immunohistochemistry. For in-vivo visualization ultrasound biomicroscopy (UBM) was performed on 12 human subjects. RESULTS Fine zonular fibres originated from the valleys and lateral walls of the most anterior pars plicata that covers the anterior and inner circular ciliary muscle portion. These most anterior zonules (MAZ) showed attachments either to the anterior or posterior tines or they inserted directly onto the surface of the lens. At the site of origin, the course of the MAZ merged into the connective tissue fibres connecting the adjacent pigmented epithelium to the ciliary muscle. Numerous afferent terminals directly at the site of this MAZ-origin were connected to the intrinsic nervous network of the ciliary muscle. CONCLUSIONS A newly described set of zonular fibres features the capabilities to register the tensions of the zonular fork and lens capsule. The close location and neural connection towards the circular ciliary muscle portion could provide the basis for stabilization and readjustment of focusing that serves fast and fine-tuned accommodation and disaccommodation.
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Affiliation(s)
| | - Mary Ann Croft
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Paul L Kaufman
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Wisconsin National Primate Research Center, University of Wisconsin, Madison, USA
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Abstract
Trabecular meshwork (TM) and ciliary muscle contraction and relaxation function together to provide control of outflow. The active role the TM plays in the regulation of intraocular pressure (IOP) is mediated by cytoskeletal and contractility mechanisms as well as signal/transduction factors that mediate its response to stressors. This complex system is altered with age and the glaucomas, and it can be difficult to differentiate between the various etiological effects/agents. Factors such as a compromised antioxidant defense system and altered extracellular matrix metabolism are known to contribute to impaired outflow and may be common to primary open-angle glaucoma, exfoliation syndrome, and exfoliation glaucoma (XFG). Genes differentially expressed in diseased ocular tissue or in cultured HTM cell models, and thus implicated in the disease process, include SOD2, ALDH1A1, MGST1, LOX, and LOXL1, elements of the transforming growth factor-β/bone morphogenetic protein/SMAD signaling pathways, connective tissue growth factor, matrix metalloproteinase-2, a tissue inhibitor of metalloproteinases also known as TIMP-2, and endothelin-1 (ET-1). In exfoliation syndrome and XFG fibrillar, proteinaceous extracellular material is produced in excess and accumulates in both outflow pathways but does not always lead to elevated IOP. Locally produced material may accumulate in the intertrabecular spaces, juxtacanalicular (JCT) meshwork, and the inner wall of Schlemm's canal as a result of a combination of both excessive synthesis and insufficient degradation. An increase in JCT plaque and decreased cellularity in the TM are thought to contribute to decreased outflow facility in glaucoma patients, but XFG patient specimens show reduced extracellular plaque material in the JCT, and the structural integrity of trabecular endothelial cells is mostly retained and cellularity remains unchanged. The distinctions between causes/effects of structural changes leading to reduced outflow/elevated IOP are important for developing effective, individualized treatment strategies.
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Flügel-Koch CM, Tektas OY, Kaufman PL, Paulsen FP, Lütjen-Drecoll E. Morphological alterations within the peripheral fixation of the iris dilator muscle in eyes with pigmentary glaucoma. Invest Ophthalmol Vis Sci 2014; 55:4541-51. [PMID: 24938519 DOI: 10.1167/iovs.13-13765] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To analyze the peripheral fixation of the iris dilator muscle in normal eyes and in eyes with pigmentary glaucoma (PG). METHODS Using 63 control eyes (age 18 months-99 years), the peripheral iris dilator was investigated by light microscopy, immunohistochemistry, and electron microscopy. Development was studied using 18 differently aged fetal eyes stained immunohistochemically against α-smooth muscle (SM) actin. The peripheral iris dilator muscle in PG was analyzed using semithin and ultrathin sections of six glutaraldehyde-fixed eyes from three donors aged 38, 62, and 74 years. RESULTS In normal eyes, the peripheral end of the iris dilator muscle is arranged in a sphincter-like manner. Arcade-shaped tendinous connections associated with myofibroblasts (iridial strands) anchor the iris dilator within the elastic-fibromuscular ciliary meshwork that also serves as fixation area for the elastic tendons of the inner ciliary muscle portions. The iridial strands are innervated and can adapt their length during accommodation. The PG eyes show incomplete circular bundles and iridial strands that are mainly anchored to the iris stroma and the flexible uveal parts of the trabecular meshwork. CONCLUSIONS The normal anchorage of the peripheral iris dilator and its presumably neuronally regulated length adaptation stabilize the peripheral iris during accommodation. Insufficient fixation in PG could promote posterior bowing of the iris with rubbing against the zonular fibers and pigment liberation from the iris pigmented epithelium.
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Affiliation(s)
- Cassandra M Flügel-Koch
- Department of Anatomy II, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
| | - Ozan Y Tektas
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
| | - Paul L Kaufman
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Friedrich P Paulsen
- Department of Anatomy II, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
| | - Elke Lütjen-Drecoll
- Department of Anatomy II, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
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Abstract
PURPOSE To investigate the changes occurring in the axial length, choroidal thickness, and anterior biometrics of the eye during a 10-minute near task performed in downward gaze. METHODS Twenty young adult subjects (10 emmetropes and 10 myopes) participated in this study. To measure ocular biometrics in downward gaze, an optical biometer was inclined on a custom-built height- and tilt-adjustable table. Baseline measures were collected after each subject performed a distance primary gaze control task for 10 minutes to provide washout period for previous visual tasks before each of three different accommodation/gaze conditions. These other three conditions included a near task (2.5 diopters [D]) in primary gaze and a near (2.5 D) and a far (0 D) accommodative task in downward gaze (25 degrees), all for 10 minutes' duration. Immediately after and then 5 and 10 minutes from the commencement of each trial, measurements of ocular biometrics (e.g., anterior biometrics, axial length, choroidal thickness, and retinal thickness) were obtained. RESULTS Axial length increased with accommodation and was significantly greater for downward gaze with accommodation (mean ± SD change, 23 ± 13 μm at 10 minutes) compared with primary gaze with accommodation (8 ± 15 μm at 10 minutes) (p < 0.05). A small amount of choroidal thinning was also found during accommodation that was statistically significant in downward gaze (13 ± 14 μm at 10 minutes; p < 0.05). Accommodation in downward gaze also caused greater changes in anterior chamber depth and lens thickness compared with accommodation in primary gaze. CONCLUSIONS Axial length, choroidal thickness, and anterior eye biometrics change significantly during accommodation in downward gaze as a function of time. These changes seem to be caused by the combined influence of biomechanical factors (i.e., extraocular muscle forces, ciliary muscle contraction) associated with near tasks in downward gaze.
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16
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Goel R, Murthy KR, Srikanth SM, Pinto SM, Bhattacharjee M, Kelkar DS, Madugundu AK, Dey G, Mohan SS, Krishna V, Prasad TK, Chakravarti S, Harsha HC, Pandey A. Characterizing the normal proteome of human ciliary body. Clin Proteomics 2013; 10:9. [PMID: 23914977 PMCID: PMC3750387 DOI: 10.1186/1559-0275-10-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/16/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The ciliary body is the circumferential muscular tissue located just behind the iris in the anterior chamber of the eye. It plays a pivotal role in the production of aqueous humor, maintenance of the lens zonules and accommodation by changing the shape of the crystalline lens. The ciliary body is the major target of drugs against glaucoma as its inhibition leads to a drop in intraocular pressure. A molecular study of the ciliary body could provide a better understanding about the pathophysiological processes that occur in glaucoma. Thus far, no large-scale proteomic investigation has been reported for the human ciliary body. RESULTS In this study, we have carried out an in-depth LC-MS/MS-based proteomic analysis of normal human ciliary body and have identified 2,815 proteins. We identified a number of proteins that were previously not described in the ciliary body including importin 5 (IPO5), atlastin-2 (ATL2), B-cell receptor associated protein 29 (BCAP29), basigin (BSG), calpain-1 (CAPN1), copine 6 (CPNE6), fibulin 1 (FBLN1) and galectin 1 (LGALS1). We compared the plasma proteome with the ciliary body proteome and found that the large majority of proteins in the ciliary body were also detectable in the plasma while 896 proteins were unique to the ciliary body. We also classified proteins using pathway enrichment analysis and found most of proteins associated with ubiquitin pathway, EIF2 signaling, glycolysis and gluconeogenesis. CONCLUSIONS More than 95% of the identified proteins have not been previously described in the ciliary body proteome. This is the largest catalogue of proteins reported thus far in the ciliary body that should provide new insights into our understanding of the factors involved in maintaining the secretion of aqueous humor. The identification of these proteins will aid in understanding various eye diseases of the anterior segment such as glaucoma and presbyopia.
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Affiliation(s)
- Renu Goel
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Department of Biotechnology, Kuvempu University, Shankaraghatta, Shimoga 577 451, Karnataka, India
| | - Krishna R Murthy
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690 525, Kerala, India.,Vittala International Institute Of Ophthalmology, Bangalore 560 085, Karnataka, India
| | - Srinivas M Srikanth
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Centre of Excellence in Bioinformatics, Bioinformatics Centre, School of Life Sciences, Pondicherry University, Puducherry 605 014, India
| | - Sneha M Pinto
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Manipal University, Madhav Nagar, Manipal 576104, Karnataka, India
| | - Mitali Bhattacharjee
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690 525, Kerala, India
| | - Dhanashree S Kelkar
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690 525, Kerala, India
| | - Anil K Madugundu
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India
| | - Gourav Dey
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India
| | - Sujatha S Mohan
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Department of Biotechnology, Kuvempu University, Shankaraghatta, Shimoga 577 451, Karnataka, India.,Research Unit for Immunoinformatics, RIKEN Research Center for Allergy and Immunology, RIKEN Yokohama Institute, Kanagawa 230 0045, Japan
| | - Venkatarangaiah Krishna
- Department of Biotechnology, Kuvempu University, Shankaraghatta, Shimoga 577 451, Karnataka, India
| | - Ts Keshava Prasad
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690 525, Kerala, India.,Manipal University, Madhav Nagar, Manipal 576104, Karnataka, India
| | - Shukti Chakravarti
- Johns Hopkins University School of Medicine, Baltimore 21205, MD, USA.,Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD, USA.,Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - H C Harsha
- Institute of Bioinformatics, International Technology Park, Bangalore 560 066, India
| | - Akhilesh Pandey
- Johns Hopkins University School of Medicine, Baltimore 21205, MD, USA.,McKusick-Nathans Institute of Genetic Medicine, Departments of Biological Chemistry, Oncology and Pathology, Johns Hopkins University School of Medicine, Baltimore 21205, MD, USA
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17
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Croft MA, Nork TM, McDonald JP, Katz A, Lütjen-Drecoll E, Kaufman PL. Accommodative movements of the vitreous membrane, choroid, and sclera in young and presbyopic human and nonhuman primate eyes. Invest Ophthalmol Vis Sci 2013; 54:5049-58. [PMID: 23745005 DOI: 10.1167/iovs.12-10847] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE We report, for the first time to our knowledge, dynamic movements of the vitreous membrane and peripheral choroid during accommodation, and age-related changes in the anterior sclera. METHODS We studied 11 rhesus monkeys (ages 6-27 years) and 12 human subjects (ages 19-65 years). Accommodation was induced pharmacologically in human subjects and by central electrical stimulation in the monkeys. Ultrasound biomicroscopy, endoscopy, and contrast agents were used to image various intraocular structures. RESULTS In the monkey, the anterior hyaloid membrane bows backward during accommodation in proportion to accommodative amplitude and lens thickening. A cleft exists between the pars plicata region and the anterior hyaloid membrane, and the cleft width increases during accommodation from 0.79 ± 0.01 mm to 1.01 ± 0.02 mm in young eyes (n = 2, P < 0.005), as fluid from the anterior chamber flows around the lens equator toward the cleft. In the older eyes the cleft width was 0.30 ± 0.19 mm, which during accommodation increased to 0.45 ± 0.20 mm (n = 2). During accommodation the ciliary muscle moved forward by approximately 1.0 mm, pulling forward the choroid, retina, vitreous zonule, and the neighboring vitreous interconnected with the vitreous zonule. Among the humans, in the older eyes the scleral contour bowed inward in the region of the limbus, compared to the young eyes. CONCLUSIONS The monkey anterior hyaloid bends posteriorly during accommodation in proportion to accommodative amplitude and the sclera bows inward with increasing age in both species. Future descriptions of the accommodative mechanism, and approaches to presbyopia therapy, may need to incorporate these findings.
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Affiliation(s)
- Mary Ann Croft
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53792-3220, USA.
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18
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Buckhurst H, Gilmartin B, Cubbidge RP, Nagra M, Logan NS. Ocular biometric correlates of ciliary muscle thickness in human myopia. Ophthalmic Physiol Opt 2013; 33:294-304. [DOI: 10.1111/opo.12039] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 01/28/2013] [Indexed: 01/18/2023]
Affiliation(s)
- Hetal Buckhurst
- School of Health Professions; Peninsula Allied Health Centre; Plymouth University; Plymouth; UK
| | - Bernard Gilmartin
- School of Life & Health Sciences; Ophthalmic Research Group; Aston University; Birmingham; UK
| | - Robert P Cubbidge
- School of Life & Health Sciences; Ophthalmic Research Group; Aston University; Birmingham; UK
| | - Manbir Nagra
- School of Life & Health Sciences; Ophthalmic Research Group; Aston University; Birmingham; UK
| | - Nicola S Logan
- School of Life & Health Sciences; Ophthalmic Research Group; Aston University; Birmingham; UK
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19
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Blur and disparity are complementary cues to depth. Curr Biol 2012; 22:426-31. [PMID: 22326024 DOI: 10.1016/j.cub.2012.01.033] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Revised: 12/03/2011] [Accepted: 01/17/2012] [Indexed: 11/23/2022]
Abstract
Estimating depth from binocular disparity is extremely precise, and the cue does not depend on statistical regularities in the environment. Thus, disparity is commonly regarded as the best visual cue for determining 3D layout. But depth from disparity is only precise near where one is looking; it is quite imprecise elsewhere. Away from fixation, vision resorts to using other depth cues-e.g., linear perspective, familiar size, aerial perspective. But those cues depend on statistical regularities in the environment and are therefore not always reliable. Depth from defocus blur relies on fewer assumptions and has the same geometric constraints as disparity but different physiological constraints. Blur could in principle fill in the parts of visual space where disparity is imprecise. We tested this possibility with a depth-discrimination experiment. Disparity was more precise near fixation and blur was indeed more precise away from fixation. When both cues were available, observers relied on the more informative one. Blur appears to play an important, previously unrecognized role in depth perception. Our findings lead to a new hypothesis about the evolution of slit-shaped pupils and have implications for the design and implementation of stereo 3D displays.
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20
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Gabelt BT, Kaufman PL, Rasmussen CA. Effect of nitric oxide compounds on monkey ciliary muscle in vitro. Exp Eye Res 2010; 93:321-7. [PMID: 21147103 DOI: 10.1016/j.exer.2010.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/21/2010] [Accepted: 12/06/2010] [Indexed: 01/22/2023]
Abstract
The effects of various nitric oxide compounds and their inhibitors on monkey ciliary muscle contraction in vitro were investigated in both the longitudinal and circular vectors. The responses to nitric oxide compounds in carbachol precontracted ciliary muscle consisted of an initial relaxation often followed by recovery to near carbachol precontracted levels while the compound was still present. Sodium nitroprusside produced the greatest relaxation responses (nearly 100% relaxation in both vectors at 10(-3) M). The highest concentrations of isosorbide dinitrate (10(-4) M) and L-arginine (10(-3) M) produced relaxation responses of approximately 50% in both vectors. 8-Bromo cyclic GMP produced the smallest relaxation responses (25-35%). Nitric oxide synthase inhibition enhanced carbachol contraction up to 20% in the longitudinal but not the circular vector. Phosphodiesterase inhibition did not further enhance the relaxation response to L-arginine. Guanylate cyclase inhibition partially attenuated the relaxation response to sodium nitroprusside. Nitric oxide generating compounds were effective in relaxing precontracted monkey ciliary muscle in vitro. Endogenous production of nitric oxide is likely involved in the regulation of the contractile response in monkey ciliary muscle. Nitric oxide generating compounds may have potential value in therapeutic areas where modulation of ciliary muscle tension is desirable.
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Affiliation(s)
- B'Ann T Gabelt
- Department of Ophthalmology & Visual Sciences, University of Wisconsin, 600 Highland Ave, Madison, WI 53792, United States.
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21
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Neuhuber W, Schrödl F. Autonomic control of the eye and the iris. Auton Neurosci 2010; 165:67-79. [PMID: 21071284 DOI: 10.1016/j.autneu.2010.10.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 08/08/2010] [Accepted: 10/13/2010] [Indexed: 10/18/2022]
Abstract
The vertebrate eye receives innervation from ciliary and pterygopalatine parasympathetic and cervical sympathetic ganglia as well as sensory trigeminal axons. The sympathetic and parasympathetic pathways represent the classical "core" of neural regulation of ocular homeostasis. Sensory trigeminal neurons are also involved in autonomic regulation by both providing the afferent limb of various reflexes and exerting their peptide-mediated local effector function. This arrangement is remarkably conserved throughout vertebrate classes although significant modifications are observed in anamniotes, in particular their irises. In higher primates and birds, intrinsic choroidal neurons emerged as a significant additional innervation component. They most likely mediate local vascular regulation and other local homeostatic tasks in foveate eyes. This review across the vertebrate classes outfolds the complex neuronal regulatory underpinnings across vertebrates that ensure proper visual function.
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