Fig 29 - uploaded by Elke Lütjen-Drecoll
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Electron micrograph of the ciliary epithelium in the apical part of the ciliary processes ( x 8,500). The epithelium consist of two layers of secretory cells, the nonpigmented epithelium (NPE) and the pigmented epithelium (PE). The basal surface of the NPE shows numerous infoldings (black arrows) and is covered by the internal limiting membrane (black arrowheads). The cytoplasm of the NPE contains numerous mitochondria (M). Near the nucleus (N), there are
Source publication
Keywords:ciliary epithelium;ciliary muscle;electron microscopy;human eye
Citations
... The purpose of this study was to investigate the morphological changes of the ciliary muscle before and after phacoemulsification, aiming to better understand the underlying causes of post-operative glaucoma. The ciliary muscle consists of three layers: longitudinal fibers, radial fibers, and circular fibers (26). To examine these morphological changes from different perspectives, we categorized the parameters into two distinct groups. ...
... Therefore, the location of each fiber was estimated based on anatomical knowledge. The measurements were conducted assuming that longitudinal fibers are positioned just beneath the sclera and run parallel to the iris, radial fibers are situated between longitudinal and circular fibers, and circular fibers originate from the posterior iris (8,26,52). Although these parameters were obtained through estimation, this study is significant as the first veterinary research that anatomically classifies ciliary muscles and explains their individual roles. ...
Introduction
This study investigates the relationship between ciliary muscle dynamics, thickness, and the regulation of intraocular pressure (IOP), focusing on the progression of cataracts and changes post-phacoemulsification. It explores how these factors impact canine ocular health, particularly in the context of cataract development and subsequent surgical intervention.
Materials and methods
Data was collected using Ultrasound Biomicroscopy (UBM) from dogs at the Veterinary Medical Teaching Hospital of Chungbuk National University, Korea. The study involved 57 eyes from 35 dogs, categorized into five groups: 13 normal eyes, 14 with incipient cataracts, 12 with immature cataracts, 6 with mature cataracts, and 12 post-phacoemulsification. UBM measurements assessed various ciliary muscle parameters including ciliary body axial length (CBAXL), ciliary process-sclera angle (CPSA), longitudinal fibers of ciliary muscle thickness (Lf-CMT), and longitudinal and radial fibers of ciliary muscle thickness (LRf-CMT).
Results
Findings indicated a decrease in CBAXL and an increase in Lf-CMT as cataracts progressed in severity. Post-phacoemulsification, there was a notable increase in CBAXL and a decrease in CPSA, Lf-CMT, and LRf-CMT, compared to both cataractous and normal eyes. Regression analysis revealed a significant positive association between CBAXL and IOP, alongside a negative association between Lf-CMT and IOP. These findings suggest that variations in ciliary muscle dynamics and thickness, as influenced by cataract progression and phacoemulsification, have distinct impacts on intraocular pressure.
Discussion
The study proposes that phacoemulsification leads to ciliary muscle contraction, causing an inward and anterior movement of the ciliary muscle. This movement results in the narrowing of the ciliary cleft and constriction of the unconventional outflow pathway, potentially causing an increased risk of glaucoma post-surgery. Our research contributes to understanding the anatomical and physiological changes in the canine eye following cataract surgery and underscores the importance of monitoring IOP and ciliary muscle dynamics in these patients.
... While the exact orientation of muscle fibres is not discernible in these OCT measurements, posterior ciliary muscle thinning indicates that portions of the longitudinal fibres have been recruited into a radial and then circular orientation, as demonstrated by an increase in the anterior muscle thickness in the OCT images. 40 It is unknown whether thin apical ciliary fibres predispose an individual to decreased accommodative ability or whether they result from AI, but the results seen here suggest that thickening of the ciliary muscle may be at least in part responsible for the improvements in accommodation reported post-therapy. Accommodative/vergence therapy required accommodative demands at levels approximately two to six times greater than those associated with typical daily close work. ...
Purpose:
Recent evidence suggests that the ciliary muscle apical fibres are most responsive to accommodative load; however, the structure of the ciliary muscle in individuals with accommodative insufficiency is unknown. This study examined ciliary muscle structure in individuals with accommodative insufficiency (AI). We also determined the response of the ciliary muscle to accommodative/vergence therapy and increasing accommodative demands to investigate the muscle's responsiveness to workload.
Methods:
Subjects with AI were enrolled and matched by age and refractive error with subjects enrolled in another ciliary muscle study as controls. Anterior segment optical coherence tomography was used to measure the ciliary muscle thickness (CMT) at rest (0D), maximum thickness (CMTMAX) and over the area from 0.75 mm (CMT0.75) to 3 mm (CMT3) posterior to the scleral spur of the right eye. For those with AI, the ciliary muscle was also measured at increasing levels of accommodative demand (2D, 4D and 6D), both before and after accommodative/vergence therapy.
Results:
Sixteen subjects with AI (mean age = 17.4 years, SD = 8.0) were matched with 48 controls (mean age = 17.8 years, SD = 8.2). On average, the controls had 52-72 μm thicker ciliary muscles in the apical region at 0D than those with AI (p = 0.03 for both CMTMAX and CMT 0.75). Differences in thickness between the groups in other regions of the muscle were not statistically significant. After 8 weeks of accommodative/vergence therapy, the CMT increased by an average of 22-42 μm (p ≤ 0.04 for all), while AA increased by 7D (p < 0.001).
Conclusions:
This study demonstrated significantly thinner apical ciliary muscle thickness in those with AI and that the ciliary muscle can thicken in response to increased workload. This may explain the mechanism for improvement in signs and symptoms with accommodative/vergence therapy.
... Although ADAMTSL4 has not yet been isolated in the zonules, impairment of this function may result in impaired zonular formation and maintenance [20,21]. ADAMTSL4 has been isolated in the ciliary processes [21], which form the attachment site of the zonules [22]. Similarly, pathogenic ADAMTSL4 variants have been demonstrated in a murine model to result in unstable anchorage of zonule fibers to the lens capsule [23]. ...
Purpose:
ADAMTSL4-associated ectopia lentis is a rare autosomal recessive condition that is primarily associated with crystalline lens displacement. However, the prevalence of other ocular and systemic manifestations of this condition is poorly understood. In this study, we summarize the ocular and systemic phenotypic spectrum of this condition.
Methods:
A cross-sectional case study series of four individuals with biallelic pathogenic or likely pathogenic ADAMTSL4 variants was performed alongside a literature review of individuals with ADAMTSL4-associated ectopia lentis on September 29, 2021. Ocular and systemic findings, complications, and genetic findings of all four individuals were collected and summarized.
Results:
The phenotypic spectrum across 91 individuals sourced from literature and four individuals from this case study series was highly variable. The main ocular phenotypes included ectopia lentis (95/95, 100%), ectopia lentis et pupillae (18/95, 19%), iris transillumination (13/95, 14%), iridodonesis (12/95, 13%), persistent pupillary membrane (12/95, 13%), and early-onset cataract or lens opacities (12/95, 13%). Anterior segment features other than ectopia lentis appeared to be exclusively associated with biallelic loss of function variants (p<0.001). Pupillary block glaucoma had a prevalence of 1%. Post-lensectomy complications included retinal detachment (6/41, 15%), elevated intraocular pressure (4/41, 10%), and aphakic glaucoma (1/41, 2%). Most individuals were not reported to have had systemic features (69/95, 73%).
Conclusions:
The clinical phenotype of ADAMTSL4-associated ectopia lentis was summarized and expanded. Clinicians should be aware of the varied ocular phenotype and the risks of retinal detachment, ocular hypertension, and glaucoma in the diagnosis and management of this condition.
... The second is an efferent-motor latency, representing the time taken for the resultant neural signal to travel from the Edinger-Westphal nucleus down the IIIrd cranial nerve, relay in the ciliary ganglion and reach the ciliary muscle. The motor latency is reduced by the fact that the axons from the ciliary ganglion to the ciliary muscle are myelinated, unusually for postganglionic axons of the autonomous nervous system (Tamm & Lütjen-Drecoll, 1996;Warwick, 1954). The sensory and motor latencies have been estimated as T sens ∼200ms and T mot ∼100ms respectively (Gamlin et al., 1994;Schor, Lott, Pope, & Graham, 1999;Wilson, 1973), and we will fix the values in our model at these values. ...
... This deficiency is perhaps especially important since our model assumes that visual feedback from the retinal images is the only feedback available to the accommodative control system. (Stretch receptors in the scleral spur base of the ciliary body could potentially also provide sensory feedback used in accommodative control (Tamm, Flügel, Stefani, & Lütjen, 1994;Tamm & Lütjen-Drecoll, 1996), but at present nothing is known about whether or how this occurs, and it has not been included in any model of accommodative control.) ...
Ocular accommodation is the process of adjusting the eye's crystalline lens so as to bring the retinal image into sharp focus. The major stimulus to accommodation is therefore retinal defocus, and in essence, the job of accommodative control is to send a signal to the ciliary muscle which will minimize the magnitude of defocus. In this article, we first provide a tutorial introduction to control theory to aid vision scientists without this background. We then present a unified model of accommodative control that explains properties of the accommodative response for a wide range of accommodative stimuli. Following previous work, we conclude that most aspects of accommodation are well explained by dual integral control, with a "fast" or "phasic" integrator enabling response to rapid changes in demand, which hands over control to a "slow" or "tonic" integrator which maintains the response to steady demand. Control is complicated by the sensorimotor latencies within the system, which delay both information about defocus and the accommodation changes made in response, and by the sluggish response of the motor plant. These can be overcome by incorporating a Smith predictor, whereby the system predicts the delayed sensory consequences of its own motor actions. For the first time, we show that critically-damped dual integral control with a Smith predictor accounts for adaptation effects as well as for the gain and phase for sinusoidal oscillations in demand. In addition, we propose a novel proportional-control signal to account for the power spectrum of accommodative microfluctuations during steady fixation, which may be important in hunting for optimal focus, and for the nonlinear resonance observed for low-amplitude, high-frequency input. Complete Matlab/Simulink code implementing the model is provided at https://doi.org/10.25405/data.ncl.14945550.
... The study of CB has gained significant attention because of its involvement in glaucoma and myopia. Several studies have been conducted on humans to provide histological information about the CB, but all have encountered postmortem shrinkage problems [16,17]. UBM can be used to measure any quadrant on living subjects, as it is unaffected by shrinkage. ...
Background:
The imaging and analysis of the ciliary body (CB) are valuable in many potential clinical applications. This study aims to demonstrate the anatomy characteristics of CB using radial and transverse imaging of ultrasound biometric microscopy (UBM) in healthy Chinese subjects, and to explore the determining factors.
Methods:
Fifty-four eyes of 30 healthy Chinese subjects were evaluated. Clinical data, including age, body mass index (BMI), intraocular pressure (IOP), axial length (AL), and lens thickness (LT), were collected. Radial and transverse UBM measurements of the ciliary body were performed. Anterior chamber depth (ACD), ciliary sulcus diameter (CSD), ciliary process length (CPL), ciliary process density (CPD), ciliary process area (CPA), ciliary muscle area (CMA), ciliary body area (CBA), ciliary body thickness (CBT0, CBT1, and CBTmax), anterior placement of ciliary body (APCB), and trabecular-ciliary angle (TCA) of four (superior, nasal, inferior, and temporal) quadrants were measured.
Results:
The average CPL was 0.513 ± 0.074 mm, and the average CPA was 0.890 ± 0.141 mm2. CPL and CPA tended to be longer and larger in the superior quadrant (p < 0.001) than in the other three quadrants. Average CPL was significantly correlated with AL (r = 0.535, p < 0.001), ACD (r = 0.511, p < 0.001), and LT (r = -0.512, p < 0.001). Intraclass correlation coefficient (ICC) scores were high for CPL (0.979), CPD (0.992), CPA (0.966), CMA (0.963), and CBA (0.951).
Conclusions:
In healthy Chinese subjects, CPL was greatest in the superior quadrant, followed by the inferior, temporal, and nasal quadrants, and CPA was largest in the superior quadrant, followed by the tempdoral, inferior, and nasal quadrants. Transverse UBM images can be used to measure the anatomy of the ciliary process with relatively good repeatability and reliability.
... 33 The ciliary body can be divided into two parts, the anterior part and the posterior part, and the posterior part is connected to the vitreous body. 34 The choroid, attached to the sclera, is anterior to the ciliary body. 2 The retina belongs to the central nervous system, and its development is similar to that of the cerebral cortex. 35,36 The central retina, which consists of the macula, results in the highest vision for humans. ...
Current clinical practice in ocular disease treatment dosage forms primarily relies on eye drops or eye ointments, which face significant challenges in terms of low bioavailability profiles, rapid removal from the administration site, and thus ineffective therapeutic efficiency. Hydrogel has several distinct properties in semi-solid thermodynamics and viscoelasticity, as well as diverse functions and performance in biocompatibility and degradation, making it extremely promising for overcoming the challenges in current ocular treatment. In this review, the most recent developments in the use of hydrogel biomaterials in ocular therapy are presented. These sophisticated hydrogel biomaterials with diverse functions, aimed at therapeutic administration for ocular treatment, are further classified into several active domains, including drug delivery system, surface repair patch, tissue-engineered cornea, intraocular lens, and vitreous substitute. Finally, the possible strategies for future design of multifunctional hydrogels by combining materials science with biological interface are proposed.
... Accommodation is the process by which the eye changes the crystalline lens' refractive power to maintain a clear image of objects at different viewing distances. The ciliary muscle, a smooth muscle that consists of three types of muscle fibers [1] is the only active element of this mechanism. It is responsible for changing the shape of the eye lens by reducing the tension of the anterior zonules [2]. ...
The purpose of this study was to provide an in-depth analysis of the ciliary muscle’s (CM) morphological changes during accommodation by evaluating CM thickness (CMT) profiles. The CM of 15 near-emmetropic subjects (age 20-39) was imaged via optical coherence tomography (OCT) during far (0 D) and near vision (3 D). A custom-made Java-based program was used for semi-automatic CM segmentation and thickness measurements. CMT profiles were generated to determine regions of the largest shape changes. The results revealed on average a thinning within the first 0.25 mm and a thickening from 0.36 to 1.48 mm posterior to scleral spur when accommodating from 0 to 3 D. In contrast to previous analyses, this method offers pixel-wise reconstruction of CM shapes and quantification of accommodative change across the entire muscle boundary.
... The ciliary body is composed of melanocytes, muscle cells, fibroblasts, epithelium, and pigmented epithelial cells (Fig. 2). The ciliary body is highly vascularized and has been shown to contain lymphatics (Chen, 2009;Nakao et al., 2012;Tamm and Lutjen-Drecoll, 1996;Yucel et al., 2009). Putative antigen-presenting cells (resident macrophages and dendritiform cells) have been found in the ciliary processes (McMenamin et al., 1994). ...
... The smooth muscle is organized in a ring overlying the ciliary processes and is regulated by autonomic innervation. The ciliary body is responsible for changes in lens thickness and curvature during accommodation (Tamm and Lutjen-Drecoll, 1996). The anterior thick ciliary processes (pars plicata), are responsible for the secretion of the aqueous humor from the posterior chamber into the anterior chamber. ...
The complement system is a vital component of the immune-priveliged human eye that is always active at a low-grade level, preventing harmful intraocular injuries caused by accumulation of turnover products and controlling pathogens to preserve eye homeostasis and vision. The complement system is a double-edged sword that is essential for protection but may also become harmful and contribute to eye pathology. Here, we review the evidence for the involvement of complement system dysregulation in age-related macular degeneration, glaucoma, uveitis, and neuromyelitis optica, highlighting the relationship between morphogical changes and complement system protein expression and regulation in these diseases. The potential benefits of complement inhibition in age-related macular degeneration, glaucoma, uveitis, and neuromyelitis optica are abundant, as are those of further research to improve our understanding of complement-mediated injury in these diseases.
... 38 It is known that the ciliary muscle is made of smooth muscle too. 39 Myopia study shows that a thicker posterior region of the ciliary muscle was associated with increased myopic refractive error. 40,41 The active component of panax notoginseng is panax notoginseng saponins (PNS) including anticoagulant activity. ...
Objective: To explore whether the traditional Chinese medicine (TCM) Bu Jing Yi Shi Tablets alters the expression of scleral TGF-β1 and Smad3 in guinea pigs with form-deprivation myopia (FDM).
Methods: Sixty-five guinea pigs were randomly divided into control, model, low-, medium-, and high-dose treatment groups. Except for the control group, FDM was induced by covering the right eye of each animal with opaque latex. The treatment groups were gavaged with different suspension concentrations of Bu Jing Yi Shi Tablets. Refraction and axial length were performed before and after myopia induction. At the end of the experiment, all right eyes were extracted, and scleral sections were prepared for staining and TGF-β1 and Smad3 immunohistochemistry. Scleral thickness and area, the scleral fibroblast quantity, and scleral TGF-β1 and Smad3 expressions were measured.
Results: The 5 FDM groups had the same initial axial length and diopter, the final diopter and axial length of the model group were significantly increased compared with the control group and treatment groups (P
... Upon morphological observation, the ciliary muscle appeared to span its natural attachment points (ora serrata & scleral spur) at 1 day of age (Figure 7). 34 Visual determination was done in a similar manner to that of the Bailey laboratory. 35 Therefore, it appears that the muscle has reached its general conformation by the time of birth. ...
... 37 Likewise, while much is known about the unique histology of the ciliary muscle, there is little information on how its size changes over time. 31,34,38 With regards to histology, it is known that the ciliary muscle is made of smooth muscle, yet it possesses characteristic of both smooth and skeletal muscle. For example, it has α-smooth muscle actin and dense bodies, which are primarily seen in smooth muscle. ...
... For example, it has α-smooth muscle actin and dense bodies, which are primarily seen in smooth muscle. 34,39,40 At the same time, it has numerous mitochondria, rough endoplasmic reticulum, and dense bands with a regular alignment, which is primarily seen skeletal muscle. 34,39 Furthermore, humans are able to voluntarily activate their ciliary muscle to produce accommodation; this feature is also more typical of skeletal muscle. ...
Purpose:
The purpose of this study was to develop a method for quantifying guinea pig ciliary muscle volume (CMV) and to determine its relationship to age and ocular biometric measurements.
Methods:
Six albino guinea pigs' eyes were collected at each of five ages (n = 30 eyes). Retinoscopy and photography were used to document refractive error, eye size, and eye shape. Serial sections through the excised eyes were made and then labeled with an α-smooth muscle actin antibody. The ciliary muscle was then visualized with an Olympus BX51 microscope, reconstructed with Stereo Investigator (MBF Bioscience), and analyzed using Neurolucida Explorer (MBF Bioscience). Full (using all sections) and partial (using a subset of sections) reconstruction methods were used to determine CMV.
Results:
There was no significant difference between the full and partial volume determination methods (p = 0.86). The mean (±SD) CMV of the 1-, 10-, 20-, 30-, and 90-day-old eyes was 0.40 (±0.16) mm, 0.48 (±0.13) mm, 0.67 (±0.15) mm, 0.86 (±0.35) mm, and 1.09 (±0.63) mm, respectively. Ciliary muscle volume was significantly correlated with log age (p = 0.001), ocular length (p = 0.003), limbal circumference (p = 0.01), and equatorial diameter (p = 0.003). It was not correlated with refractive error (p = 0.73) or eye shape (p = 0.60). Multivariate regression determined that biometric variables were not significantly associated with CMV after adjustment for age.
Conclusions:
Three-dimensional reconstruction was an effective means of determining CMV. These data provide evidence that ciliary muscle growth occurs with age in tandem with eye size in normal albino guinea pigs. Additional work is needed to determine the relationship between CMV and abnormal ocular growth.
