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Investigative Ophthalmology & Visual... Apr 2021The prevalence of myopia has markedly increased in East and Southeast Asia, and pathologic consequences of myopia, including myopic maculopathy and high... (Review)
Review
The prevalence of myopia has markedly increased in East and Southeast Asia, and pathologic consequences of myopia, including myopic maculopathy and high myopia-associated optic neuropathy, are now some of the most common causes of irreversible blindness. Hence, strategies are warranted to reduce the prevalence of myopia and the progression to high myopia because this is the main modifiable risk factor for pathologic myopia. On the basis of published population-based and interventional studies, an important strategy to reduce the development of myopia is encouraging schoolchildren to spend more time outdoors. As compared with other measures, spending more time outdoors is the safest strategy and aligns with other existing health initiatives, such as obesity prevention, by promoting a healthier lifestyle for children and adolescents. Useful clinical measures to reduce or slow the progression of myopia include the daily application of low-dose atropine eye drops, in concentrations ranging between 0.01% and 0.05%, despite the side effects of a slightly reduced amplitude of accommodation, slight mydriasis, and risk of an allergic reaction; multifocal spectacle design; contact lenses that have power profiles that produce peripheral myopic defocus; and orthokeratology using corneal gas-permeable contact lenses that are designed to flatten the central cornea, leading to midperipheral steeping and peripheral myopic defocus, during overnight wear to eliminate daytime myopia. The risk-to-benefit ratio needs to be weighed up for the individual on the basis of their age, health, and lifestyle. The measures listed above are not mutually exclusive and are beginning to be examined in combination.
Topics: Accommodation, Ocular; Contact Lenses; Disease Progression; Eyeglasses; Global Health; Humans; Myopia; Prevalence; Refraction, Ocular
PubMed: 33909032
DOI: 10.1167/iovs.62.5.6 -
Investigative Ophthalmology & Visual... Apr 2021The role of accommodation in myopia development and progression has been debated for decades. More recently, the understanding of the mechanisms involved in... (Review)
Review
The role of accommodation in myopia development and progression has been debated for decades. More recently, the understanding of the mechanisms involved in accommodation and the consequent alterations in ocular parameters has expanded. This International Myopia Institute white paper reviews the variations in ocular parameters that occur with accommodation and the mechanisms involved in accommodation and myopia development and progression. Convergence is synergistically linked with accommodation and the impact of this on myopia has also been critiqued. Specific topics reviewed included accommodation and myopia, role of spatial frequency, and contrast of the task of objects in the near environment, color cues to accommodation, lag of accommodation, accommodative-convergence ratio, and near phoria status. Aspects of retinal blur from the lag of accommodation, the impact of spatial frequency at near and a short working distance may all be implicated in myopia development and progression. The response of the ciliary body and its links with changes in the choroid remain to be explored. Further research is critical to understanding the factors underlying accommodative and binocular mechanisms for myopia development and its progression and to guide recommendations for targeted interventions to slow myopia progression.
Topics: Accommodation, Ocular; Convergence, Ocular; Disease Progression; Humans; Myopia; Refraction, Ocular; Vision, Binocular
PubMed: 33909034
DOI: 10.1167/iovs.62.5.4 -
Journal of Optometry 2022Convergence insufficiency (CI) is a common binocular vision (BV) disorder characterized by difficulty in maintaining motor fusion at near, which affects approximately... (Review)
Review
Convergence insufficiency (CI) is a common binocular vision (BV) disorder characterized by difficulty in maintaining motor fusion at near, which affects approximately 7.5 percent of the population. Diagnostic criteria for the disorder are inconsistent, ranging from one to many clinical signs. Methodology for clinical tests is inconsistent in measurement technique, visual targets, required repetitions, and normative values. This manuscript demonstrates the inconsistencies amongst published studies, and highlights the importance of consistent clinical diagnostic signs, measurement techniques, visual targets, and cut-off criteria. For each clinical sign, the recommended methodology for the procedure is described. Several studies do not take age into account when diagnosing CI in their cohorts. As such, the review emphasizes changes in diagnostic signs with age. This manuscript highlights the need for consistent and clear procedures and diagnostic criteria amongst clinicians and provides the basis for future studies in terms of diagnostic testing required for CI of varying age groups.
Topics: Accommodation, Ocular; Convergence, Ocular; Humans; Ocular Motility Disorders; Vision Disorders; Vision, Binocular
PubMed: 34963569
DOI: 10.1016/j.optom.2021.11.002 -
Comprehensive Physiology Jan 2015The autonomic nervous system influences numerous ocular functions. It does this by way of parasympathetic innervation from postganglionic fibers that originate from... (Review)
Review
The autonomic nervous system influences numerous ocular functions. It does this by way of parasympathetic innervation from postganglionic fibers that originate from neurons in the ciliary and pterygopalatine ganglia, and by way of sympathetic innervation from postganglionic fibers that originate from neurons in the superior cervical ganglion. Ciliary ganglion neurons project to the ciliary body and the sphincter pupillae muscle of the iris to control ocular accommodation and pupil constriction, respectively. Superior cervical ganglion neurons project to the dilator pupillae muscle of the iris to control pupil dilation. Ocular blood flow is controlled both via direct autonomic influences on the vasculature of the optic nerve, choroid, ciliary body, and iris, as well as via indirect influences on retinal blood flow. In mammals, this vasculature is innervated by vasodilatory fibers from the pterygopalatine ganglion, and by vasoconstrictive fibers from the superior cervical ganglion. Intraocular pressure is regulated primarily through the balance of aqueous humor formation and outflow. Autonomic regulation of ciliary body blood vessels and the ciliary epithelium is an important determinant of aqueous humor formation; autonomic regulation of the trabecular meshwork and episcleral blood vessels is an important determinant of aqueous humor outflow. These tissues are all innervated by fibers from the pterygopalatine and superior cervical ganglia. In addition to these classical autonomic pathways, trigeminal sensory fibers exert local, intrinsic influences on many of these regions of the eye, as well as on some neurons within the ciliary and pterygopalatine ganglia.
Topics: Accommodation, Ocular; Animals; Autonomic Nervous System; Eye; Humans; Intraocular Pressure; Neural Pathways; Pupil; Reflex; Regional Blood Flow; Trigeminal Nerve
PubMed: 25589275
DOI: 10.1002/cphy.c140014 -
Asia-Pacific Journal of Ophthalmology... 2020Presbyopia reduces an individual's ability to perform visual tasks at near distances. It is a global problem, affecting over a billion people worldwide. Contact lenses,... (Review)
Review
Presbyopia reduces an individual's ability to perform visual tasks at near distances. It is a global problem, affecting over a billion people worldwide. Contact lenses, glasses, refractive surgery, and intraocular lens surgery are the main modalities in presbyopia treatment, although they all have some disadvantages. Thus, there is an increasing need for effective, easy-to-use, and noninvasive approaches for treating presbyopia while not limiting patients' daily activities. Pharmacological presbyopia treatment as an alternative method has been under investigation in recent years. We reviewed all relevant articles using the keywords "presbyopia," "presbyopia treatment," "pharmacological presbyopia treatment," and "presbyopic corrections" from 2010 to February 9, 2020, and summarized the main results of clinical trials, investigating the drops used for presbyopia treatment.
Topics: Accommodation, Ocular; Cyclooxygenase 2 Inhibitors; Drug Therapy, Combination; Humans; Muscarinic Agonists; Ophthalmic Solutions; Presbyopia; Refraction, Ocular; Treatment Outcome
PubMed: 32511122
DOI: 10.1097/APO.0000000000000297 -
Clinical & Experimental Optometry Jan 2020Evidence from animal and human studies suggests that ocular growth is influenced by visual experience. Reduced retinal image quality and imposed optical defocus result... (Review)
Review
Evidence from animal and human studies suggests that ocular growth is influenced by visual experience. Reduced retinal image quality and imposed optical defocus result in predictable changes in axial eye growth. Higher order aberrations are optical imperfections of the eye that alter retinal image quality despite optimal correction of spherical defocus and astigmatism. Since higher order aberrations reduce retinal image quality and produce variations in optical vergence across the entrance pupil of the eye, they may provide optical signals that contribute to the regulation and modulation of eye growth and refractive error development. The magnitude and type of higher order aberrations vary with age, refractive error, and during near work and accommodation. Furthermore, distinctive changes in higher order aberrations occur with various myopia control treatments, including atropine, near addition spectacle lenses, orthokeratology and soft multifocal and dual-focus contact lenses. Several plausible mechanisms have been proposed by which higher order aberrations may influence axial eye growth, the development of refractive error, and the treatment effect of myopia control interventions. Future studies of higher order aberrations, particularly during childhood, accommodation, and treatment with myopia control interventions are required to further our understanding of their potential role in refractive error development and eye growth.
Topics: Accommodation, Ocular; Astigmatism; Contact Lenses, Hydrophilic; Corneal Wavefront Aberration; Eye; Eyeglasses; Humans; Myopia; Orthokeratologic Procedures; Refractive Errors
PubMed: 31489693
DOI: 10.1111/cxo.12960 -
Clinical & Experimental Optometry Jan 2020Modern methods of measuring the refractive state of the eye include wavefront sensors which make it possible to monitor both static and dynamic changes of the ocular... (Review)
Review
Modern methods of measuring the refractive state of the eye include wavefront sensors which make it possible to monitor both static and dynamic changes of the ocular wavefront while the eye observes a target positioned at different distances away from the eye. In addition to monitoring the ocular aberrations, wavefront refraction methods allow measurement of the accommodative response while viewing with the eye's habitual chromatic and monochromatic aberrations present, with these aberrations removed, and with specific aberrations added or removed. A large number of experiments describing the effects of accommodation on aberrations and vice versa are reviewed, pointing out the implications for fundamental questions related to the mechanism of accommodation.
Topics: Accommodation, Ocular; Corneal Wavefront Aberration; Humans; Refraction, Ocular; Visual Acuity
PubMed: 31284325
DOI: 10.1111/cxo.12938 -
JAMA Ophthalmology Nov 2020Because studies have suggested that atropine might slow the progression of myopia in children, randomized clinical trials are warranted to understand this potential... (Randomized Controlled Trial)
Randomized Controlled Trial
IMPORTANCE
Because studies have suggested that atropine might slow the progression of myopia in children, randomized clinical trials are warranted to understand this potential causal relationship.
OBJECTIVE
To evaluate the efficacy and safety of atropine, 0.01%, eyedrops on slowing myopia progression and axial elongation in Chinese children.
DESIGN, SETTING, AND PARTICIPANTS
This was a randomized, placebo-controlled, double-masked study. A total of 220 children aged 6 to 12 years with myopia of -1.00 D to -6.00 D in both eyes were enrolled between April 2018 and July 2018 at Beijing Tongren Hospital, Beijing, China. Cycloplegic refraction and axial length were measured at baseline, 6 months, and 12 months. Adverse events were also recorded.
INTERVENTIONS
Patients were randomly assigned in a 1:1 ratio to atropine, 0.01%, or placebo groups to be administered once nightly to both eyes for 1 year.
MAIN OUTCOMES AND MEASURES
Mean changes and percentage differences in myopia progression and axial elongation between atropine, 0.01%, or placebo groups.
RESULTS
Of 220 participants, 103 were girls (46.8%), and the mean (SD) age was 9.64 (1.68) years. The mean (SD) baseline refractive error and axial length were -2.58 (1.39) D and 24.59 (0.87) mm. Follow-up at 1 year included 76 children (69%) and 83 children (75%) allocated into the atropine, 0.01%, and placebo groups, respectively, when mean myopia progression was -0.49 (0.42) D and -0.76 (0.50) D in the atropine, 0.01%, and placebo groups (mean difference, 0.26 D; 95% CI, 0.12-0.41 D; P < .001), with a relative reduction of 34.2% in myopia progression. The mean (SD) axial elongation in the atropine, 0.01%, group was 0.32 (0.19) mm compared with 0.41 (0.19) mm in the placebo group (mean difference, 0.09 mm; 95% CI, 0.03-0.15 mm; P = .004), with relative reduction of 22.0% in axial elongation. Fifty-one percent and 13.2% of children progressed by at least 0.50 D and 1.00 D in the atropine, 0.01%, group, compared with 69.9% and 34.9% in the placebo group. No serious adverse events related to atropine were reported.
CONCLUSIONS AND RELEVANCE
While the clinical relevance of the results cannot be determined from this trial, these 1-year results, limited by approximately 70% follow-up, suggest that atropine, 0.01%, eyedrops can slow myopia progression and axial elongation in children and warrant future studies to determine longer-term results and potential effects on slowing sight-threatening pathologic changes later in life.
TRIAL REGISTRATION
http://www.chictr.org.cn Identifier: ChiCTR-IOR-17013898.
Topics: Accommodation, Ocular; Atropine; Axial Length, Eye; Child; China; Disease Progression; Double-Blind Method; Female; Follow-Up Studies; Humans; Incidence; Male; Mydriatics; Myopia, Degenerative; Ophthalmic Solutions; Refraction, Ocular; Retrospective Studies; Treatment Outcome; Visual Acuity
PubMed: 33001210
DOI: 10.1001/jamaophthalmol.2020.3820 -
Journal of Robotic Surgery Oct 2023Stereopsis may be an advantage of robotic surgery. Perceived robotic ergonomic advantages in visualisation include better exposure, three-dimensional vision, surgeon... (Review)
Review
Stereopsis may be an advantage of robotic surgery. Perceived robotic ergonomic advantages in visualisation include better exposure, three-dimensional vision, surgeon camera control, and line of sight screen location. Other ergonomic factors relating to visualisation include stereo-acuity, vergence-accommodation mismatch, visual-perception mismatch, visual-vestibular mismatch, visuospatial ability, visual fatigue, and visual feedback to compensate for lack of haptic feedback. Visual fatigue symptoms may be related to dry eye or accommodative/binocular vision stress. Digital eye strain can be measured by questionnaires and objective tests. Management options include treatment of dry eye, correction of refractive error, and management of accommodation and vergence anomalies. Experienced robotic surgeons can use visual cues like tissue deformation and surgical tool information as surrogates for haptic feedback.
Topics: Humans; Robotic Surgical Procedures; Asthenopia; Depth Perception; Accommodation, Ocular; Ergonomics
PubMed: 37204648
DOI: 10.1007/s11701-023-01618-7 -
Indian Journal of Ophthalmology Aug 2020Asthenopic and related symptoms are a major problem in school-going children. With the inception of computers and other gadgets for near work, the unseen problems... (Review)
Review
Asthenopic and related symptoms are a major problem in school-going children. With the inception of computers and other gadgets for near work, the unseen problems arising out of constant and continuous near work, are on the rise. Parents wander from pillar to post, seeking respite from their child's constant complaints from near work; but despite best spectacle correction and avoidance of excessive near work, the complaints continue. Studies have shown that the majority of these problems arise from defects in accommodation, even in a young child. Therefore, various aspects of accommodation deficiencies have to be studied clinically, detected, and treated to ameliorate the symptoms.
Topics: Accommodation, Ocular; Asthenopia; Child; Computers; Eyeglasses; Humans; Schools
PubMed: 32709767
DOI: 10.4103/ijo.IJO_1973_18