Ciliary Muscle Research Articles

Characteristics of the Ciliary Body in Healthy Chinese Subjects Evaluated by Radial and Transverse Imaging of Ultrasound Biometric Microscopy.

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.

Effects of General Anesthesia on Ocular Refraction

ABSTRACT Purpose General anesthesia alters the autonomic nervous system. This study aimed to investigate the effects of general anesthesia on objective ocular refraction. Methods A total of 57 patients (112 eyes) under 15 years of age who underwent strabismus surgery under general anesthesia were included in this study. Objective refraction values, corneal refraction values, and pupil diameter were measured using a HandyRef-K, a hand-held refractive keratometer, in the operating room before and during general anesthesia before strabismus surgery. Results The spherical power of the myopic eye increased from −0.75 D to −2.29 D (diopter); the cylindrical power increased from −0.90 D to −1.39 D (p < .01 for all). The corneal refractive power decreased by an average of 0.25 D (p < .01). The spherical refractive power was negatively correlated with the age and the amount of change between cycloplegia before general anesthesia and during general anesthesia (r = −0.32, p < .05). Conclusions General anesthesia resulted in manifestation of myopia as noted by the objective refraction values. Corneal refractive values flatten under the same conditions, suggesting that the contraction of the ciliary muscles was the main cause of myopia. We speculate that this change was due to parasympathetic dominance and contraction of the ciliary muscles during general anesthesia.

Ciliary Muscle Dimension Changes With Accommodation Vary in Myopia and Emmetropia.

PurposeThe purpose of this study was to determine whether accommodation-induced changes in ciliary muscle dimensions vary between emmetropes and myopes, and the effect of the image analysis method.MethodsSeventy adults aged 18 to 27 years consisted of 25 people with emmetropia (spherical equivalent refraction [SER] +0.21 ± 0.36 diopters [D]) and 45 people with myopia (−2.84 ± 1.72 D). There were 23 people with low myopia (>−3 D) and 22 people with moderate myopia (−3 to −6 D). Right eye ciliary muscles were imaged (Visante OCT; Carl Zeiss Meditec) at 0 D and 6 D demands. Measures included ciliary muscle length (CML), ciliary muscle curved length (CMLarc), maximum ciliary muscle thickness (CMTmax), CMT1, CMT2, and CMT3 (fixed distances 1–3 mm from the scleral spur), CM25, CM50, and CM75 (proportional distances 25%–75%). Linear mixed model analysis determined effects of refractive groups, race, and demand on dimensions. Significance was set at P < 0.05.ResultsMyopic eyes had greater CML and CMLarc nasally than emmetropic eyes. Myopic eyes had thicker muscles than emmetropic eyes at nasal positions, except CM25 and CMT3, and at CM75 temporally. During accommodation and only nasally, CML reduced in emmetropic and myopic eyes, and CMLarc reduced in myopic eyes only. During accommodation, both nasally and temporally, muscles thickened anteriorly (CMT1 and CM25) and thinned posteriorly (CMT3 and CM75) except for temporal CM75. Moderate myopic eyes had greater temporal CMLarc than low myopic eyes, and the moderate myopes had thicker muscles both nasally and temporally using fixed and proportional distances.ConclusionsPeople with myopia had longer and thicker ciliary muscles than people with emmetropia. During accommodation, the anterior muscle thickened and the curved nasal muscle length shortened, more in myopic than in emmetropic eyes. The fixed distance method is recommended for repeat measures in the same individual. The proportional distance method is recommended for comparisons between refractive groups.

Objective characteristics of accommodation in present-day schoolchildren with progressive myopia

Purpose: to study the accommodative function in contemporary schoolchildren using the method of computer accommodography.Material and methods. 74 children aged 10–16 (54 with different degrees of myopia and the control group of 20 emmetropic children) were tested on a Righton Speedy-K ver. MF-1 computer accommodograph to determine the accommodative response to accommodation stimulus (by calculating the coefficient of the accommodative response, CAR) and the contraction of ciliary muscle fibers (by determining the microfluctuation coefficient, CMF).Results. In groups of patients with emmetropia and weak myopia, CAR and CMF were found to exceed the normal values. The low myopia group demonstrated especially pronounced changes. In moderate and high myopia, the CAO is significantly lower than in low myopia or emmetropia, while the CMF also exceeds normal values.Conclusion. The spastic component of accommodation is of great importance in the pathogenesis of progressive myopia of present-day schoolchildren, which is expressed in the strengthening of the accommodation response with regard to the accommodation stimulus and pathological frequency increase of accommodative microfluctuations.

Novel Three-Dimensional and Biocompatible Lift-Off Method for Selective Metallization of a Scleral Contact Lens Electrode for Biopotential Detection.

Presbyopia describes the eye's physiological loss of the ability to see close objects clearly. The adaptation to different viewing distances, termed accommodation, is achieved by a change in the curvature of the eye lens induced by the ciliary muscle. A possible approach to correct presbyopia could be to detect the ciliary muscle's neuromuscular signals during accommodation and transfer these signals electronically to a biomimetic, micro-optical system to provide the necessary refractive power. As a preliminary step toward such a described system, a novel three-dimensional and biocompatible lift-off method was developed. In addition, the influence of the distance between the electrically conducting surfaces of the lens on the accommodated signal amplitudes was investigated. Compared to the conventional masking methods, this process has the advantage that three-dimensional surfaces can be masked with biocompatible gelling sugar by utilizing a direct writing process with a dispensing robot. Since gelling sugar can be used at room temperature and is water-soluble, the process presented is suitable for materials that should not be exposed to organic solvents or excessively high temperatures. Apart from investigating the shrinkage behavior of the gelling sugar during the physical vapor deposition (PVD) coating process, this paper also describes the approaches used to partially coat a commercial scleral contact lens with an electrically conductive material. It was shown that gelling sugar withstands the conditions during the PVD processes and a successful lift-off was performed. To investigate the influence of the spacing between the electrically conductive regions of the contact lens on the measured signals, three simplified electrode configurations with different distances were fabricated using a 3D printer. By testing these in an experimental setup, it could be demonstrated that the distance between the conductive surfaces has a significant influence on the amplitude. Regarding the described lift-off process using gelling sugar, it was found that the dispensing flow rate has a direct influence on the line uniformity. Future work should address the influence of the viscosity of the gelling sugar as well as the diameter of the cannula. It is assumed that they are the prevailing limitations for the lateral resolution.

Accommodative movements of the choroid in the optic nerve head region of human eyes, and their relationship to the lens

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.

Diagnosis and Management of Post Traumatic Recurrent Unilateral Accommodative Spasm—A Case Report

ABSTRACT Spasm of accommodation refers to constant contraction of the ciliary muscles of the eye, which fail to relax. Neurological issues, head injury, and psychogenic factors can lead to spasm of accommodation, which is generally bilateral. This case report describes the clinical presentation of traumatic, unilateral accommodative spasm in an army person. A 26-year-old male presented with complaints of diminution of near vision in the left eye noticed accidentally. History revealed a blunt injury in the eyebrow region of the left eye two months back. His best corrected visual acuity was 6/6, 0.8 M (N6) in the right eye and 6/9, 2.5 M (N18) in the left eye. Accommodative response was documented using an open-field autorefractometer that showed asymmetry in the accommodation response and pupillary diameter between the two eyes. One percent Atropine sulfate eye ointment – twice a day for 3 days – was prescribed. On the fourth day, the spasm was resolved in the left eye. Pre- and post-Atropine administration, lens thickness measurements were documented, which showed significant changes. Accommodative facility exercise was initiated after the pharmacological management. Unilateral accommodative spasm is rare and needs careful investigations. Objective assessment of accommodative response and lens thickness measurement play a vital role in confirming the diagnosis.

Automated segmentation of the ciliary muscle in OCT images using fully convolutional networks.

Quantifying shape changes in the ciliary muscle during accommodation is essential in understanding the potential role of the ciliary muscle in presbyopia. The ciliary muscle can be imaged in-vivo using OCT but quantifying the ciliary muscle shape from these images has been challenging both due to the low contrast of the images at the apex of the ciliary muscle and the tedious work of segmenting the ciliary muscle shape. We present an automatic-segmentation tool for OCT images of the ciliary muscle using fully convolutional networks. A study using a dataset of 1,039 images shows that the trained fully convolutional network can successfully segment ciliary muscle images and quantify ciliary muscle thickness changes during accommodation. The study also shows that EfficientNet outperforms other current backbones of the literature.

The Oculomotor Nerve: Anatomy and Pathology

The oculomotor nerve is the third cranial nerve, exiting the brainstem in the medial border of the cerebral peduncle, from where it crosses straight to the superior orbital fissure. It is a purely motor nerve responsible for the innervation of all the extraocular muscles, except the superior oblique and lateral rectus muscles. It also has parasympathetic pre-ganglionic fibers, responsible for the innervation of sphincter pupillae and ciliary muscles. Magnetic resonance imaging (MRI) is the best imaging exam to evaluate patients with clinical signs of third cranial nerve palsy. The oculomotor nerve can be affected by several diseases, such as congenital malformations, trauma, inflammatory or infectious diseases, vascular disorders, and neoplasms. This article aims to review the oculomotor nerve anatomy, discuss the best MRI techniques to evaluate each nerve segment, and demonstrate the imaging aspect of the diseases that most commonly affect it.

Ciliary muscle thickness in adults with Down syndrome.

The relationship between ciliary muscle thickness (CMT), age and refractive error was investigated to determine if CMT, like other anterior ocular anatomy, differs in adults with Down syndrome (DS). The CMT of 33 adults with DS was imaged using anterior segment optical coherence tomography. Images from the right eye obtained 45minutes after cycloplegia (1% tropicamide, 2.5% phenylephrine) were analysed to calculate thickness at 1, 2 and 3mm posterior to the scleral spur (CMT1, CMT2, CMT3), maximum thickness (CMTMAX) and apical thickness (AT=CMT1 - CMT2). Spherical equivalent refractive error was determined by clinical refraction using both non-dilated and dilated measures. Multivariate regression analysis evaluated the relationship between CMT and refractive error while controlling for subject age. Images were analysed from 26 subjects (mean age (SD) 29 years; mean refractive error (SD): -0.90 (5.03) D, range: -15.75 to +5.13D). Mean (SD) CMT decreased with posterior position (CMT1: 804 (83) μm; CMT2: 543 (131) μm; CMT3: 312 (100) μm). Mean (SD) CMTMAX and AT was 869 (57) μm and 260 (84) μm, respectively. There was a significant linear correlation indicating thinning CMT with increasing age for CMT1 and CMT2 (p≤0.05). CMT2 and CMT3 had a significant negative correlation (thicker muscle with increasing myopic refractive error) (p≤0.01). AT had a significant positive correlation (thicker muscle with increasing hyperopic refractive error) (p<0.01). Ciliary muscle thickness in participants with DS was found to be in a similar range with similar refractive error trends to previous reports of individuals without DS. However, it is important to note that the refractive error trends were driven by individuals with moderate to high levels of myopia.

Intraocular accommodative movements in monkeys; relationship to presbyopia

Our goal was to quantify the age-related changes in the dynamic accommodative movements of the vitreous and aqueous humor in iridic, aniridic, phakic and aphakic primate eyes.Six bilaterally iridic and four bilaterally iridectomized rhesus monkeys, ranging in age from 6 to 25 years, received a stimulating electrode in the midbrain Edinger-Westphal nucleus to induce accommodation, measured by a Hartinger coincidence refractometer. One of the four iridectomized monkeys underwent unilateral extracapsular and another monkey underwent intracapsular lens extraction. Eyes were imaged utilizing specialized techniques and contrast agents to resolve intraocular structures.During accommodation the anterior hyaloid membrane and the posterior lens capsule bowed backward. Central vitreous fluid and structures/strands moved posteriorly toward the optic nerve region as peripheral vitreous, attached to the vitreous zonule, was pulled forward by ciliary muscle contraction. Triamcinolone particles injected intravitreally were also observed in the anterior chamber and moved from the anterior chamber toward the cleft of the anterior hyaloid membrane and then further posteriorly into the vitreous-filled cleft between the vitreous zonule and the ciliary body pars plana. These accommodative movements occurred in all eyes, and declined with age.There are statistically significant accommodative movements of various intravitreal structures. The posterior/anterior fluid flow between the anterior chamber and the vitreous compartments during accommodation/disaccommodation represents fluid displacement to allow/facilitate lens thickening. The posterior accommodative movement of central vitreous fluid may result from centripetal compression of the anterior tips of the cistern-like structure attached to the vitreous zonule, and posterior displacement of the central trunk of the cistern during ciliary muscle contraction and centripetal muscle movement. The findings may have implications for presbyopia.

In vivo analysis of ciliary muscle in myopic Chinese young adults using ArcScan Insight® 100.

To analyse the morphological characteristics of the ciliary muscle (CM) and to explore its relationship with different ocular biometric parameters in myopic young Chinese adults. This observational, cross-sectional study included 50 right eyes from 50myopic adults. The CM area (CMA), CM thickness (CMT) and CM length (CML) were measured using the ArcScan Insight® 100. CMT was determined at three points: 1.0mm (CMT-1), 2.0mm (CMT-2) and 3.0mm (CMT-3) posterior to the scleral spur. CML was measured on the scleral (CMLs) and vitreous (CMLv) aspects. The spherical equivalent refraction (SER), axial length (AL) and subfoveal choroidal thickness (SFCT) were examined to determine their associations with CM parameters (CMA, CML and CMT). The mean SER and AL were -4.39±2.29 D and 25.61±1.15mm, respectively. Compared with the nasal CMA, CML and CMT (CMT-1, CMT-2 and CMT-3) findings, the temporal CM parameters (CMA, CMLs, CMLv, CMT-1, CMT-2 and CMT-3) were found to be significantly thicker (all p<0.001, except CMLv and CMT-1; p<0.01). The nasal CMA was associated with the average corneal curvature (r=0.30, p=0.03) and SER (r=-0.30, p=0.04). Nasal and temporal CMT-2 were negatively correlated with SER (r=-0.33 and -0.32, respectively, both p<0.05). There was no correlation between CM parameters (except nasal CMLs, r=0.31, p=0.03) and SFCT, or between CM parameters and either the AL or anterior chamber depth (all p>0.05). These results suggest that there is temporal versus nasal asymmetry of the CM. CMA, CMT or CML did not vary with axial growth of the eye. The CM is not simply stretched as the eye elongates in myopic young adults.

Mechanical Stress Modulates Calcium-Activated-Chloride Currents in Differentiating Lens Cells.

During accommodation, the lens changes focus by altering its shape following contraction and relaxation of the ciliary muscle. At the cellular level, these changes in shape may be accompanied by fluid flow in and out of individual lens cells. We tested the hypothesis that some of this flow might be directly modulated by pressure-activated channels. In particular, we used the whole cell patch clamp technique to test whether calcium-activated-chloride channels (CaCCs) expressed in differentiating lens cells are activated by mechanical stimulation. Our results show that mechanical stress, produced by focally perfusing the lens cell at a constant rate, caused a significant increase in a chloride current that could be fully reversed by stopping perfusion. The time course of activation and recovery from activation of the flow-induced current occurred rapidly over a time frame similar to that of accommodation. The flow-induced current could be inhibited by the TMEM16A specific CaCC blocker, Ani9, suggesting that the affected current was predominantly due to TMEM16A chloride channels. The mechanism of action of mechanical stress did not appear to involve calcium influx through other mechanosensitive ion channels since removal of calcium from the bath solution failed to block the flow-induced chloride current. In conclusion, our results suggest that CaCCs in the lens can be rapidly and reversibly modulated by mechanical stress, consistent with their participation in regulation of volume in this organ.

Prevention of accommodation disorders and myopia in children

Background. An important role in the structure of ophthalmic pathology is played by myopia, especially rapidly progressing in adolescence, and accommodation disorders, which are, in fact, the precursors and companions of myopia. The purpose was to prevent accommodation disorders and mild myopia in children of different age groups by using dietary supplements Doppelherz® Kinder Eye vitamins with lutein and Doppelherz® Kinder Glycine. Materials and methods. One hundred and three children of diffe-rent age groups underwent functional examination against the background of treatment: group I — primary school age, prepubertal period (6–11 years) — 24 children, group II — middle school age, pubertal period (12–18 years) — 79 children, 24 of them had problems of the neck and collar zone associated with computer load. Standard examination methods were used. Results. After the course of the proposed therapy, the Haidinger’s phenomenon decreased to 5.70 ± 0.01 conventional units (p &lt; 0.05) in the first group; up to 4.60 ± 0.03 conventional units in 55 children of the second group without problems in the neck and collar zone and up to 5.40 ± 0.02 conventional units in 24 children who had such problems (p &lt; 0.02). Conclusions. Using Doppelherz® Kinder Eye vitamins with lutein and Doppelherz® Kinder Glycine improves the functioning of the ciliary muscle. Under the influence of treatment, visual acuity and accommodation reserves increased, and the power of optical correction decreased. The positive influence of Doppelherz® Kinder Eye vitamins with lutein and Doppelherz® Kinder Glycine on the increase in the functional activity of the fovea-afferent system and the accommodative function of the visual analyzer in spasm of accommodation and mild myopia has been proven.

Comparison of accommodation and accommodative micro-fluctuation after implantable collamer lens and LASIK surgery for myopia

BackgroundTo longitudinally analyze and compare the accommodative micro-fluctuation (MFs) and accommodative function between myopic patients after implantable collamer lens (ICL) implantation and laser in situ keratomileusis (LASIK).MethodsPatients with good corrected visual acuity (20/20 or better) and underwent ICL (V4c) and LASIK for myopic-correction (ranging from − 3.50 to − 8.50 D) were recruited. Refraction, amplitude of accommodation (AMP), accommodative lag, higher-order aberration (HOA), and MFs were recorded before surgery and 1 and 3 months after surgery. The ACOMEREF automatic refractor was used to measure the high-frequency component (HFC) of the MFs, which suggested tension of the ciliary muscle.ResultsThe study comprised 120 eyes. At 3 months after surgery, the manifest refractive spherical equivalent of the ICL and LASIK groups were − 0.11 and − 0.09 D, respectively (p = 0.46). HFC values were significantly higher at 1 month (p = 0.03) and 3 months postoperatively (p = 0.03) in the ICL group compared to that in the LASIK group. The ocular HOA of the ICL group was 1.08 ± 0.43 μm, which was lower than the LASIK group 1.45 ± 0.54 μm (p = 0.01). No significant differences in AMP and accommodative lag between groups were noted at 3 months postoperatively. There was a positive correlation between HFC and vault of the ICL lens (r2 = 0.14, p = 0.005). There were no correlations between HFC and ocular HOA and postoperative MRSE in the two groups (all p>0.05).ConclusionsThe HFC increased significantly after an early period of ICL implantation compared to laser in situ keratomileusis for myopic correction, which indicated increased tension of the ciliary muscle, and had a positive correlation on the vault of the ICL lens; However, studies with longer follow-up time and more structural evaluation are needed.

TRPV4: Cell type-specific activation, regulation and function in the vertebrate eye.

The architecture of the vertebrate eye is optimized for efficient delivery and transduction of photons and processing of signaling cascades downstream from phototransduction. The cornea, lens, retina, vasculature, ciliary body, ciliary muscle, iris and sclera have specialized functions in ocular protection, transparency, accommodation, fluid regulation, metabolism and inflammatory signaling, which are required to enable function of the retina-light sensitive tissue in the posterior eye that transmits visual signals to relay centers in the midbrain. This process can be profoundly impacted by non-visual stimuli such as mechanical (tension, compression, shear), thermal, nociceptive, immune and chemical stimuli, which target these eye regions to induce pain and precipitate vision loss in glaucoma, diabetic retinopathy, retinal dystrophies, retinal detachment, cataract, corneal dysfunction, ocular trauma and dry eye disease. TRPV4, a polymodal nonselective cation channel, integrate non-visual inputs with homeostatic and signaling functions of the eye. The TRPV4 gene is expressed in most if not all ocular tissues, which vary widely with respect to the mechanisms of TRPV4 channel activation, modulation, oligomerization, and participation in protein- and lipid interactions. Under- and overactivation of TRPV4 may affect intraocular pressure, maintenance of blood-retina barriers, lens accommodation, neuronal function and neuroinflammation. Because TRPV4 dysregulation precipitates many pathologies across the anterior and posterior eye, the channel could be targeted to mitigate vision loss.

ОБГРУНТУВАННЯ ЕФЕКТИВНОСТІ НОВОГО МЕТОДУ М’ЯЗОВОЇ ЕКСПРЕС-РЕЛАКСАЦІЇ ДЛЯ ЗНЯТТЯ ЗОРОВОГО ПЕРЕНАПРУЖЕННЯ

Relevance. The main reason of increase of myopia morbidity in the world is the raise of the eye strain at a close distance from the eyes and the complete absence of technical requirements for electronic devices, computers, artificial light sources regarding physiologically acceptable effects on the visual organ. The aim of the research is to substantiate, develop and study the effectiveness of a new muscle express relaxation method to relieve eye strain. Material and methods. 18 students took part in the research. According to the aim, the study was conducted for 7 days. In daylight, once a day for 60 minutes, students worked on the text on a smartphone, then performed exercises for rapid muscle relaxation. Results. Using the proposed method of assessing visual endurance individual functional characteristics of accommodative apparatus in different students were established. The use of the suggested method of muscle express relaxation promotes visual endurance, depending on individual characteristics in each particular case. Key conclusions. The suggested method of muscle express relaxation calculates all components of myopia pathogenesis and is aimed at restoring blood supply to eye tissues, improving their trophism and relieving strain of the ciliary muscle. The positive result of the study is confirmed by the proposed functional research methods. Taking into account individual characteristics of the endurance of the accommodative apparatus of the eye, the method of muscle express relaxation can be recommended for widespread use.

Quality of life of a patient with computer vision syndrome depending on the type of accommodative astenopia

Purpose: a comparative assessment of the quality of life (QOL) of patients with symptoms of computer vision syndrome (CVS), depending on the type of accommodative asthenopia: habitual excessive accommodation stress (HEAS) and the asthenic form of accommodative asthenopia (AFAA). Material and methods. 60 patients aged 22–34 engaged in visually extensive work who had typical asthenopic complaints were examined. The main criterion for diagnosing the type of asthenopia was the coefficient of ciliary muscle microfluctuation, measured by objective accommodation on a Righton Speedy-I device (Japan). The patients were divided into two groups of 30 people each with similar age and sex distribution, corresponding to the two forms of asthenopia studied. The main method of QOL examination was the study of an innovative CVS-22 questionnaire filled in by the testees. Results. The comparative assessment of the overall test indicator revealed no significant differences between the examined groups of patients with HEAS (QOL = 40.2 ± 1.2 pts) and AFAA (QOL = 42.2 ± 1.0 pts), p &gt; 0.05. For some of the complaints, certain differences were found, partly associated with the pathogenesis of HEAS and AFAA, however, they do not fully reflect the “specificity” of the main types of accommodative asthenopia. Conclusion. The results obtained indicate the absence of reliable subjective diagnostic criteria of CVS. The fact may be associated with a wide range of risk factors for the development of functional disorders of the body in general and the visual system in particular when the patients is engaged in activities requiring the use of electronic systems in information management.

Detailed morphology of tentacular apparatus and central nervous system in Owenia borealis (Annelida, Oweniidae)

The Oweniidae are marine annelids with many unusual features of organ system, development, morphology, and ultrastructure. Together with magelonids, oweniids have been placed within the Palaeoannelida, a sister group to all remaining annelids. The study of this group may increase our understanding of the early evolution of annelids (including their radiation and diversification). In the current research, the morphology and ulta-anatomy of the head region of Owenia borealis is studied by scanning electron microscopy (SEM), 3D reconstructions, transmission electron microscopy (TEM), and whole-mount immunostaining with confocal laser scanning microscopy. According to SEM, the tentacle apparatus consists of 8–14 branched arms, which are covered by monociliary cells that form a ciliary groove extending along the oral side of the arm base. Each tentacle contains a coelomic cavity with a network of blood capillaries. Monociliary myoepithelial cells of the tentacle coelomic cavity form both the longitudinal and the transverse muscles. The structure of this myoepithelium is intermediate between a simple and pseudo-stratified myoepithelium. Overall, tentacles lack prominent zonality, i.e., co-localization of ciliary zones, neurite bundles, and muscles. This organization, which indicates a non-specialized tentacle crown in O. borealis and other oweniids with tentacles, may be ancestral for annelids. TEM, light, and confocal laser scanning microscopy revealed that the head region contains the anterior nerve center comprising of outer and inner (=circumoral) nerve rings. Both nerve rings are organized as concentrated nerve plexus, which contains perikarya and neurites extending between basal projections of epithelial cells (radial glia). The outer nerve ring gives rise to several thick neurite bundles, which branch and extend along aboral side of each tentacle. Accordingly to their immunoreactivity, both rings of the anterior nerve center could be homologized with the dorsal roots of circumesophageal connectives of the typical annelids. Accordingly to its ultrastructure, the outer nerve ring of O. borealis and so-called brain of other oweniids can not be regarded as a typical brain, i.e. the most anterior ganglion, because it lacks ganglionic structure.

Dimensions of the limbus-ciliary sulcus region by OCT and correlation study in a large population.

To assess the dimensions of the limbus-ciliary sulcus region measured by swept-source optical coherence tomography (SS-OCT) and conduct a correlation study in a large healthy population. Centro Internacional de Oftalmología Avanzada, Madrid, Spain. Cross-sectional study. The dimensions of the limbus-ciliary sulcus region were measured in the temporal and nasal quadrants using a SS-OCT. The limbus-sulcus distance (LSD), the posterior iris line-ocular surface to limbus distance (PIOLD), and the angle-to-sulcus distance (ASD) were measured. These distances were then assessed for correlations with factors such as age, sex, refractive error, anterior chamber angle (ACA), ciliary muscle thickness (CMT), conjunctival-Tenon capsule thickness (CTT), and anterior scleral thickness (AST). The mean age of the participants was 41.0 ± 18.2 years (range 5 to 86) and the mean refractive error -0.75 ± 3.3 diopters (range -10 to 7). The LSD could be measured in 93.2% of the participants (625 eyes out of 670 eyes), with a mean of 1.35 ± 0.12 mm (range 0.96 to 1.75) and 1.33 ± 0.12 mm (range 1.05 to 1.68) in the temporal and nasal quadrants, respectively, and a correlation of R = 0.616 (P < .001) between them. PIOLD measured 2.22 ± 0.31 mm (1.42 to 2.98), and ASD was 0.21 ± 0.05 mm (0.01 to 0.40). No correlation was observed between LSD with age, spherical error, sex, or ACA (P ≥ .247). However, LSD exhibited the highest correlation with AST (R = 0.466), followed by CTT (R = 0.309) and CMT (R = 0.259). The SS-OCT allowed for an accurate in vivo measurement of the dimensions of the limbus-ciliary sulcus region.