Children with early onset myopia demonstrate greater accommodative variability than emmetropic children, and have similar patterns of response to adult late onset myopes. This increased variability could result in an increase in retinal blur for both near and far targets. The role of accommodative variability in the etiology of myopia is discussed.

Recent studies have promoted the concept that rectus muscles pass through connective tissue pulleys located near the equator of the eye and act, in effect, as the muscle origins. Orbital muscle fibres (facing bone) terminate in pulleys, permitting adjustment of their position independent of the global fibres responsible for rotating the eye.The structure of pulleys (or muscle sleeves) and the passage taken by their muscle fibre insertions are unclear, and a detailed description is presented here together with a review of the active pulley hypothesis. Segments including the full width of single muscles were removed from the full orbital contents of dissection room cadavers and fresh perfusion-fixed rhesus and cynomolgus monkeys and prepared for light microscopy. Thin longitudinal sections were cut as facets from resin-embedded tissue blocks and montages assembled. Interrupted serial sections of selected regions of both species and ultrathin sections of monkey material were prepared for light and electron microscopy, respectively. Slender tendons leave the orbital surface of rectus muscles at intervals, aggregating and entering sleeves in humans and monkey; less frequently, tendons pass from the global surface to sleeves or insert directly in the posterior fascia bulbi. The orbital sides of sleeve rings are continuous with the fascial canopy of the globe and are 5 -6 times as thick as the global sides; sleeve structure differs in the four recti. Medial rectus sleeves are the thickest, and contain smooth muscle, whereas little or none is present in the other rectus sleeves. Superior rectus sleeves are variable in structure and relatively insubstantial. A narrow interval separates muscles from the surrounding connective tissue equatorially in some preparations, consistent with a capacity to slide, but the tissues are contiguous in others, especially in monkey material. The structural organization of sleeves and their tendons, together with other presented factors, is inconsistent with a facility for the separate adjustment of sleeve position.The results favour the theory that sleeve tendons have just one role, to counter the viscoelastic resistance of global fascia -ocular and sleeve muscle fibres acting in unison. Whether the fragile sleeve structure can meet the physical demands of pulleys is questionable; but otherwise the veracity of the pulley hypothesis cannot be assessed from the structural relations of muscles and fascia bulbi reported.

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Results from the current study show that direct glare conditions cause increased eyestrain and orbicularis oculi contraction during reading on a computer screen. This study also indicates that exposure to direct glare affects the trapezius muscle, possibly by an interaction between the visual system, sympathetic nervous system, and head-stabilizing muscles. In addition, there were associations between the use of orbicularis oculi, trapezius blood flow, and development of neck pain independent of the lighting.

The capacity of muscle spindles in adult human extraocular muscles (EOM) to provide effective proprioception was questioned on the grounds of their peculiar morphology. Their appearance could be attributable to ageing and to test this possibility examples of infant muscle spindles have been examined. Forty encapsulated structures from five extraocular muscles removed post mortem from 4 infant patients aged 6 days, 5, 23 and 30 months were examined by means of light microscopy using serial transverse sections. Seven of them were identified as false spindles. The remaining 33 structures, identified as spindles, contained a total of 175 intrafusal fibres varying from 2 to 12 (mean: 6) in each. 130 of these fibres (74.3%) were of nuclear chain type. Unequivocal evidence of bag fibres was not found. Spindles lacked or had a limited equatorial expansion, and the inner capsule was incomplete and irregularly shaped. 45 (25.7%) of the intrafusal fibres had extrafusal features with large diameters, peripherally placed nuclei, no equatorial modification and without associated sensory nerve terminals. Serial sections revealed that a majority of the nuclear chain fibres were interrupted, fragmented or terminated abruptly, and most spindles contained at least one incomplete fibre. These observations show that the atypical features observed in adult human EOM spindles are also present in infants and are therefore not attributable to ageing.

Background Strabismus is a complex disease that has various treatment approaches each with its own advantages and drawbacks. In this context, shared decisions making (SDM) is a communication process with the provider sharing all the relevant treatment alternatives, all the benefits, and risks of each procedure, while the patient shares all the preferences and values regarding his/her choices. In that way, SDM is a bidirectional process that goes beyond the typical informed consent. Therefore, it is known a little of the extent to which SDM influences the satisfaction with the treatment outcome along with strabismus patients. To study this correlation, an SDM-Q-9 questionnaire was provided within surgical consultations where treatment decisions were made; the SDM-Q-9 aims to assess the relationship between the post-operative patient’s satisfaction and their SMD score. Methods The study is considered a prospective observational pilot study. Eligible patients were adult patients diagnosed with strabismus, who had multiple treatment options, were given at the right of choice without being driven into a physician’s preference. Ninety-three strabismus patients were asked to fill out the SDM-Q-9 questionnaire related to their perception of SDM during the entire period of strabismus treatment. After the treatment, patients were asked to rate their satisfaction level with the surgical outcome as excellent, good, fair, and poor. Descriptive statistics and the linear regression statistical tests (Spearman, Mann Whitney U, and Kriskal–Wallis) were used as analysis tools. Results The average age of the participants was 24, where 50.6% were women. The mean SDM-Q-9 score among patients was 32 (IQR = 3). The postoperative patient satisfaction was rated as being excellent by 16 (17.2%) patients, good by 38 (40.9%), fair by 32 (34.4%), and poor by 7 patients (7.5%). Data analysis by linear regression statistical tests showed a positive correlation between the SDM-Q-9 score and the patient satisfaction related to the surgery outcome (B = 0.005, p < 0.001). Criteria in assessing patients’ satisfaction were age, gender, and strabismus type. A positive correlation between SDM and real satisfaction (r = 0.834, p < 0.01) was found with age, and no significant relationship was found while taking into consideration the responder’s gender and the strabismus type. Conclusions Assessing patient satisfaction after choosing a treatment for strabismus method helped us evaluate the gaps in constructive dialogue that would lead to a positive outcome for both patient and clinician. The correlation between the SDM process and the patients’ satisfaction with surgery outcome, adjusted by age, has been established. These findings can serve as a springboard to further communicative improvements related to the SDM process and between patients and physicians, thereby consequently leading to patients’ satisfaction raise in strabismus care. The study underlines the importance of further analysis and validation of on-ground interactions among the adolescent and adult patients and the clinicians across the strabismus management trajectory. A multicentral study and its validation will follow.

The sensory and motor control of human extraocular muscles (EOMs) have been subjected to considerable speculation in ophthalmic literature, often related to infranuclear structures such as the unique complement of muscle fibres and their associated sensory organs. The intrafusal fibres do not resemble their somatic counterparts and their peculiar morphology has raised questions about their proprioceptive capacity. No Golgi tendon organs have so far been observed and the myotendinous nerve endings, previously assumed to convey sensory information, have recently been argued to merely represent constituents of the efferent innervation serving the multiply innervated muscles fibres. These observations raise questions about the overall capacity to monitor the activity created by the generous efferent nerve supply observed in these muscles. Furthermore, the argued independent activity of muscular layers and compartments suggest that the required feedback must be highly structured and more specific than previously assumed. Yet, uncertainty about the source of such information remains. The purpose of this paper is to provide a short review of neuromuscular properties of human extraocular muscles. Their functional implications and the most reputable sources of proprioception will also be discussed. The promoted views are based on pertinent literature and previous research undertaken by the authors.

Age-related binocular vision anomalies are frequently encountered during clinical examination of mature patients. Observations of both concomitant and incomitant restrictions in eye motility indicate that all oculomotor system levels are implicated, from cortical neurons down to extraocular muscles. The system can make adaptations in response to changes induced by growth and ageing, which it does by monitoring and adjusting its own performance. This adaptive mechanism, which is important for maintaining motility, spatial orientation, and perceptual stability, seems to rely on extra-retinal information about eye position in relation to the head and trunk. Receptors in the extraocular muscles and the vestibular system, assumed to contribute to this type of information, also undergo age-related changes. This may compromise their ability to assist in the adaptive process and in potential calibrations of other neural systems. Furthermore, recent observations of a dual, common, final pathway and double insertions of distal extraocular muscles suggest that muscle and tendon receptors may facilitate other, still unresolved, functions in the visual system. Consequently, age-related changes in certain mechanoreceptors may have more severe implications for ocular motility and visual functions than previously assumed.This review aims to detail some of the most frequent neurogenic and myogenic age-related changes that take place in the human oculomotor system and relevant pre-motor structures. It will also address clinical implications of these changes and the potential adaptive mechanism they initiate.