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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 -
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 -
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 -
Middle East African Journal of... 2014Presbyopia is a physiologic inevitability that causes gradual loss of accommodation during the fifth decade of life. The correction of presbyopia and the restoration of... (Review)
Review
Presbyopia is a physiologic inevitability that causes gradual loss of accommodation during the fifth decade of life. The correction of presbyopia and the restoration of accommodation are considered the final frontier of refractive surgery. Different approaches on the cornea, the crystalline lens and the sclera are being pursued to achieve surgical correction of this disability. There are however, a number of limitations and considerations that have prevented widespread acceptance of surgical correction for presbyopia. The quality of vision, optical and visual distortions, regression of effect, complications such as corneal ectasia and haze, anisometropia after monovision correction, impaired distance vision and the invasive nature of the currently techniques have limited the utilization of presbyopia surgery. The purpose of this paper is to provide an update of current procedures available for presbyopia correction and their limitations.
Topics: Accommodation, Ocular; Cornea; Humans; Lens, Crystalline; Presbyopia; Refractive Surgical Procedures; Sclera
PubMed: 24669140
DOI: 10.4103/0974-9233.124080 -
Vision Research Jul 2021Many patients with concussion experience visual symptoms following injury that lead to a diagnosis of convergence insufficiency, accommodative insufficiency, or saccadic...
Many patients with concussion experience visual symptoms following injury that lead to a diagnosis of convergence insufficiency, accommodative insufficiency, or saccadic dysfunction. However, these diagnostic categories are based on aggregates of clinical tests developed from a non-concussed population and therefore may not accurately describe visual deficits in the concussed population. Thus, we sought to understand individual metrics of visual dysfunction in chronically symptomatic post-concussion patients. This retrospective cross-sectional study included patients examined at the multidisciplinary concussion clinic (MDCC) at Boston Children's Hospital over four years. Patients aged 5-21 years who had a complete assessment of eye alignment, vergence, accommodation, and visual tracking, and had visual acuity better than or equal to 20/30 in each eye were included. Patients with history of amblyopia, strabismus, or ocular pathology were excluded. Chart review yielded 116 patients who met inclusion criteria (median age 15 years, 64% female). The majority of patients (52%) experienced a single concussion and most were sports-related (50%). Clinical data show vergence, accommodation, or visual tracking deficits in 95% of patients. A receded near point of convergence (NPC, 70/116) and reduced accommodative amplitude (63/116) were the most common deficits. Both NPC and accommodative amplitude were significantly correlated with one another (r = -0.5) and with measures of visual tracking (r = -0.34). Patients with chronic post-concussion symptoms show deficits in individual metrics of vergence, accommodation and visual tracking. The high incidence of these deficits, specifically NPC and accommodative amplitude, highlights the need for a detailed sensorimotor evaluation to guide personalized treatment following concussion.
Topics: Accommodation, Ocular; Adolescent; Child; Convergence, Ocular; Cross-Sectional Studies; Female; Humans; Male; Retrospective Studies; Vision, Binocular
PubMed: 33838503
DOI: 10.1016/j.visres.2021.03.002 -
Experimental Eye Research Apr 2022Emmetropization is affected by the temporal parameters of visual stimulation and the spectral composition of light, as well as by autonomic innervation. The goal of the...
Emmetropization is affected by the temporal parameters of visual stimulation and the spectral composition of light, as well as by autonomic innervation. The goal of the current experiments is to test the hypothesis that different types of visual stimulation interact with ocular innervation in the process of emmetropization. For that, selective lesions of the autonomic nervous system were performed in chickens: involving transection of parasympathetic input to the eye from either the ciliary ganglion, innervating accommodation and pupil responses (CGX; n = 32), or pterygopalatine ganglion, innervating choroidal blood vessels and cornea (PPGX; n = 26). After 1 week of recovery, chicks were exposed to sinusoidally modulated light (3 days, 2 Hz, 680 lux) that was either achromatic (black to white [RGB], or black to yellow [RG]), or chromatic (blue to yellow [B/Y] or red to green [R/G]). Exposure to light stimulation was followed by ocular biometry (Lenstar and a Hartinger refractometer). Surgical conditions revealed a small reduction in anterior chamber depth with CGX but no other significant changes in ocular biometry/refraction under standard light conditions. With RGB achromatic stimulation, CGX eyes produced an effect on ocular components, with a further reduction in anterior chamber depth and an increase in vitreous chamber depth, while RG stimulation showed no effect. No effect was detected in PPGX under both achromatic protocols. With chromatic stimulation, CGX with R/G modulation increased eye length, while PPGX with B/Y modulation decreased eye length. We conclude that the two different types of parasympathetic innervations have antagonistic effects on eye growth and the anterior eye when challenged with the appropriate stimulus, with possible implications for the role of choroidal blood flow in emmetropization.
Topics: Accommodation, Ocular; Animals; Chickens; Choroid; Emmetropia; Eye; Refraction, Ocular
PubMed: 35120871
DOI: 10.1016/j.exer.2022.108964 -
Acta Ophthalmologica Sep 2019Albinism degrades visual function due to developmental disorders of the eye and visual pathways, larger refractive errors, absent binocularity and poor fixation control.... (Comparative Study)
Comparative Study
PURPOSE
Albinism degrades visual function due to developmental disorders of the eye and visual pathways, larger refractive errors, absent binocularity and poor fixation control. Reading spectacles is commonly prescribed in our clinic and well tolerated. The purpose was to evaluate whether the accommodative response is typical or affected in comparison to a reference group.
METHODS
Twenty-two children with albinism (median: 13.5 years) and 12 controls (median: 13 years) underwent a full optometric examination and an objective accommodation measurement (WAM-5500 @ 6 Hz; Grand Seiko) in response to minus-lens-blur (-1, -2 and -3 D) and to a prolonged near viewing task (20 cm) for 5 min.
RESULTS
Children with albinism displayed less accommodation to minus lens-blur and during sustained near viewing (p < 0.001) compared to the reference group. Higher visual acuity correlates with a better accommodative response (r ≥ 0.5; p ≤ 0.04). The subjective and objective measures of accommodation did not correlate. The habitual reading distance was always closer than the point towards which the subjects with albinism seemed to accommodate according to the measurements at 20 cm.
CONCLUSION
Children with albinism benefits from reading spectacles due to a combination of close habitual reading distance and a poor accommodation. Objective recording of accommodation is not critical for a correct judgement of near visual function. Children already wearing reading spectacles were those with least accommodative response.
Topics: Accommodation, Ocular; Adolescent; Albinism; Child; Child, Preschool; Eyeglasses; Female; Humans; Infant; Infant, Newborn; Lens, Crystalline; Male; Reading; Refractive Errors; Vision, Binocular; Visual Acuity; Young Adult
PubMed: 30702212
DOI: 10.1111/aos.14040 -
PloS One 2022A better understanding of visual performance with Multifocal Contact Lenses (MCLs) is essential, both in young eyes, where MCLs may be prescribed to control the...
A better understanding of visual performance with Multifocal Contact Lenses (MCLs) is essential, both in young eyes, where MCLs may be prescribed to control the progression of myopia wherein the MCLs optics interact with accommodation, and in presbyopes, where MCLs are increasingly used to compensate the lack of accommodation. In this study, we evaluated the through focus visual acuity (TFVA) with center-near MCLs of three additions (low, medium and high) and without an addition (NoLens) in 10 young adults and 5 presbyopes. We studied the effect of accommodation, age and pupil diameter (in cyclopleged subjects) on visual performance. The MCLs produced a small but consistent degradation at far (by 0.925 logMAR, averaged across eyes and conditions) and a consistent benefit at near in young subjects with paralyzed accommodation (by 1.025 logMAR), and in presbyopes with both paralyzed and natural accommodation (by 1.071 logMAR, on average). TFVA in young adults with NoLens and all MCLs showed statistically significant differences (Wilcoxan, p<0.01) between natural and paralyzed accommodation, but not in presbyopes with MCLs. In young adults, VA improved with increasing pupil diameter with the HighAdd MCL (0.08 logMAR shift from 3 to 5-mm pupil size). Visual imbalance (standard deviation of VA across distances) was reduced with MCLs, and decreased significantly with increasing near add. The lowest imbalance occurred in young adults under natural accommodation and was further reduced by 13.33% with MCLs with respect to the NoLens condition. Overall, the visual performance with MCLs in young adults exceeds that in presbyopes at all distances, and was better than 0.00 logMAR over the dioptric range tested. In conclusion, the center-near lenses do not degrade the near high contrast visual acuity significantly but maintains the far vision in young adults, and produce some visual benefit at near in presbyopes.
Topics: Accommodation, Ocular; Eyeglasses; Humans; Presbyopia; Pupil; Refraction, Ocular; Young Adult
PubMed: 35298476
DOI: 10.1371/journal.pone.0263659