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American Journal of Ophthalmology Jun 2017
Topics: Accommodation, Ocular; Dominance, Ocular; Vision Tests
PubMed: 28411861
DOI: 10.1016/j.ajo.2017.03.025 -
IEEE Transactions on Bio-medical... Jan 2022Presbyopia, an age-related ocular disorder, is characterized by the loss in the accommodative abilities of the human eye. Conventional methods of correcting presbyopia...
OBJECTIVE
Presbyopia, an age-related ocular disorder, is characterized by the loss in the accommodative abilities of the human eye. Conventional methods of correcting presbyopia divide the field of view, thereby resulting in significant vision impairment. We demonstrate the design, assembly and evaluation of autofocusing eyeglasses for restoration of accommodation without dividing the field of view.
METHODS
The adaptive optics eyeglasses comprise of two variable-focus liquid lenses, a time-of-flight range sensor and low-power, dual microprocessor control electronics, housed within an ergonomic frame. Subject-specific accommodation deficiency models were utilized to demonstrate high-fidelity accommodative correction. The abilities of this system to reduce accommodation deficiency, its power consumption, response time, optical performance and MTF were evaluated.
RESULTS
Average corrected accommodation deficiencies for 5 subjects ranged from -0.021 D to 0.016 D. Each accommodation correction calculation was performed in ∼67 ms which consumed 4.86 mJ of energy. The optical resolution of the system was 10.5 cycles/degree, and featured a restorative accommodative range of 4.3 D. This system was capable of running for up to 19 hours between charge cycles and weighed ∼132 g.
CONCLUSION
The design, assembly and performance of an autofocusing eyeglasses system to restore accommodation in presbyopes has been demonstrated.
SIGNIFICANCE
The new autofocusing eyeglasses system presented in this article has the potential to restore pre-presbyopic levels of accommodation in subjects diagnosed with presbyopia.
Topics: Accommodation, Ocular; Eyeglasses; Humans; Optics and Photonics; Presbyopia; Visual Acuity
PubMed: 34232861
DOI: 10.1109/TBME.2021.3094964 -
Journal of Vision Mar 2017In this study we investigated the impact of accommodation on axial and oblique astigmatism along 12 meridians of the central 30° of visual field and explored the...
In this study we investigated the impact of accommodation on axial and oblique astigmatism along 12 meridians of the central 30° of visual field and explored the compensation of corneal first-surface astigmatism by the remainder of the eye's optical system. Our experimental evidence revealed no systematic effect of accommodation on either axial or oblique astigmatism for two adult populations (myopic and emmetropic eyes). Although a few subjects exhibited systematic changes in axial astigmatism during accommodation, the dioptric value of these changes was much smaller than the amount of accommodation. For most subjects, axial and oblique astigmatism of the whole eye are both less than for the cornea alone, which indicates a compensatory role for internal optics at all accommodative states in both central and peripheral vision. A new method for determining the eye's optical axis based on visual field maps of oblique astigmatism revealed that, on average, the optical axis is 4.8° temporal and 0.39° superior to the foveal line-of-sight in object space, which agrees with previous results obtained by different methodologies and implies that foveal astigmatism includes a small amount of oblique astigmatism (0.06 D on average). Customized optical models of each eye revealed that oblique astigmatism of the corneal first surface is negligible along the pupillary axis for emmetropic and myopic eyes. Individual variation in the eye's optical axis is due in part to misalignment of the corneal and internal components that is consistent with tilting of the crystalline lens relative to the pupillary axis.
Topics: Aberrometry; Accommodation, Ocular; Adult; Astigmatism; Corneal Topography; Emmetropia; Female; Humans; Male; Myopia; Refraction, Ocular; Visual Fields; Young Adult
PubMed: 28362902
DOI: 10.1167/17.3.24 -
Strabismus Mar 2023Accommodation anomalies are frequently caused or exacerbated by psychological problems such as anxiety. Patients share many features with those with other anxiety based...
INTRODUCTION
Accommodation anomalies are frequently caused or exacerbated by psychological problems such as anxiety. Patients share many features with those with other anxiety based somatic symptoms such as stomach-ache, palpitations and headaches. They can be difficult to treat, and the ophthalmic literature rarely goes beyond diagnosis and ocular treatment. This study reports characteristics and outcomes of a short case series of patients with accommodation spasms and weaknesses assessed objectively, and outlines a psychological approach to treatment.
METHODS
23 patients (13 severe accommodative weakness or "paralysis," 10 accommodative spasm) aged between 8-30 years, were referred to our laboratory after diagnosis by their referring clinician and exclusion of pathology or drug-related causes. Their accommodation and convergence were assessed objectively with a laboratory photorefractive method, as well as by conventional orthoptic testing and dynamic retinoscopy. All interactions with the patients used an evidence-based psychological approach, to give them insight into how stress and anxiety can cause or exacerbate eye symptoms and help them to break a vicious cycle of anxiety and risk of deterioration.
RESULTS
83% were female and 57% had previously diagnosed anxiety or dyslexia (with many more acknowledging being "worriers"). Inconsistency of responses was the rule and all showed normal responses at some time during their visit. Responses were poorly related to the visual stimuli presented and objective responses often differed from subjective. Dissociation between convergence and accommodation was more common, compared to our large, previously reported, control groups. No participant had true paralysis of accommodation. Responses often improved dramatically within one session after discussion and explanation of the strong relationship between anxiety and accommodative anomalies. None have returned for further advice or treatment.
CONCLUSIONS
Our approach explicitly addresses psychological factors in causing, or worsening, accommodation (and co-existing convergence) anomalies. Many of these patients do not realize that a certain amount of blur is normal in everyday life. Ocular symptoms are often a sign of anxiety, not the primary problem. By recognizing this, patients can be helped to address the triggering issues and symptoms often subside or resolve spontaneously. Well-meaning professionals, offering only ocular treatments, can deflect attention away from the real cause and can unwittingly be making things worse.
Topics: Humans; Female; Child; Adolescent; Young Adult; Adult; Male; Accommodation, Ocular; Retinoscopy; Orthoptics; Convergence, Ocular
PubMed: 36710250
DOI: 10.1080/09273972.2023.2171070 -
The British Journal of Ophthalmology Jun 2018To investigate the presence of asymmetrical accommodation in hyperopic anisometropic amblyopia.
BACKGROUND/AIMS
To investigate the presence of asymmetrical accommodation in hyperopic anisometropic amblyopia.
METHODS
Accommodation in each eye and binocular vergence were measured simultaneously using a PlusoptiX SO4 photorefractor in 26 children aged 4-8 years with hyperopic anisometropic amblyopia and 13 controls (group age-matched) while they viewed a detailed target moving in depth.
RESULTS
Without spectacles, only 5 (19%) anisometropes demonstrated symmetrical accommodation (within the 95% CI of the mean gain of the sound eye of the anisometropic group), whereas 21 (81%) demonstrated asymmetrical accommodation. Of those, 15 (58%) showed aniso-accommodation and 6 (23%) demonstrated 'anti-accommodation' (greater accommodation for distance than for near). In those with anti-accommodation, the response gain in the sound eye was (0.93±0.20) while that of the amblyopic eye showed a negative accommodation gain of (-0.44±0.23). Anti-accommodation resolved with spectacles. Vergence gains were typical in those with symmetrical and asymmetrical accommodation.
CONCLUSION
The majority of hyperopic anisometropic amblyopes demonstrated non-consensual asymmetrical accommodation. Approximately one in four demonstrated anti-accommodation.
Topics: Accommodation, Ocular; Amblyopia; Anisometropia; Case-Control Studies; Child; Child, Preschool; Convergence, Ocular; Female; Humans; Hyperopia; Male; Refraction, Ocular; Visual Acuity
PubMed: 29051327
DOI: 10.1136/bjophthalmol-2017-310282 -
Scientific Reports Sep 2023This study investigated the accuracy and stability of accommodative and vergence functions in children with and without hyperopia while engaged in two sustained near...
This study investigated the accuracy and stability of accommodative and vergence functions in children with and without hyperopia while engaged in two sustained near tasks. The sustained accommodative and vergence characteristics of participants without refractive correction (n = 92, aged 5-10 years) with and without hyperopia (defined as cycloplegic retinoscopy ≥ + 1.00D and less than + 5.00D) were measured using eccentric infrared photorefraction (PowerRef 3; PlusOptix, Germany). Binocular measures of accommodation and eye position were recorded while participants engaged in 2 tasks at 25 cm for 15 min each: (1) reading small print on an Amazon Kindle and (2) watching an animated movie on liquid crystal display screen. Comprehensive visual assessment, including measurement of presenting visual acuity, amplitude of accommodation, and stereoacuity was conducted. The magnitude of accommodative and vergence responses was not related to refractive error (P > 0.05). However, there were inter-task differences in the accuracy and stability of the accommodative responses across refractive groups (P < 0.05). The relationship between accommodation and vergence was not significant in both tasks (P > 0.05). However, increased accommodative and vergence instabilities were associated with total accommodative response (P < 0.05). Despite having greater accommodative demand, uncorrected hyperopes accommodate comparably to emmetropic controls. However, uncorrected hyperopes have increased instabilities in their accommodative and vergence responses, which may adversely impact their visual experience.
Topics: Child; Humans; Hyperopia; Accommodation, Ocular; Refractive Errors; Refraction, Ocular; Visual Acuity
PubMed: 37658084
DOI: 10.1038/s41598-023-41244-9 -
Journal of Visualized Experiments : JoVE Mar 2023Through the purposeful stimulation and recording of eye movements, the fundamental characteristics of the underlying neural mechanisms of eye movements can be observed....
Through the purposeful stimulation and recording of eye movements, the fundamental characteristics of the underlying neural mechanisms of eye movements can be observed. VisualEyes2020 (VE2020) was developed based on the lack of customizable software-based visual stimulation available for researchers that does not rely on motors or actuators within a traditional haploscope. This new instrument and methodology have been developed for a novel haploscope configuration utilizing both eye tracking and autorefractor systems. Analysis software that enables the synchronized analysis of eye movement and accommodative responses provides vision researchers and clinicians with a reproducible environment and shareable tool. The Vision and Neural Engineering Laboratory's (VNEL) Eye Movement Analysis Program (VEMAP) was established to process recordings produced by VE2020's eye trackers, while the Accommodative Movement Analysis Program (AMAP) was created to process the recording outputs from the corresponding autorefractor system. The VNEL studies three primary stimuli: accommodation (blur-driven changes in the convexity of the intraocular lens), vergence (inward, convergent rotation and outward, divergent rotation of the eyes), and saccades (conjugate eye movements). The VEMAP and AMAP utilize similar data flow processes, manual operator interactions, and interventions where necessary; however, these analysis platforms advance the establishment of an objective software suite that minimizes operator reliance. The utility of a graphical interface and its corresponding algorithms allow for a broad range of visual experiments to be conducted with minimal required prior coding experience from its operator(s).
Topics: Eye Movements; Saccades; Accommodation, Ocular; Movement
PubMed: 36939267
DOI: 10.3791/64808 -
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 -
Journal of Optometry 2024To evaluate the association between visual symptoms and use of digital devices considering the presence of visual dysfunctions.
PURPOSE
To evaluate the association between visual symptoms and use of digital devices considering the presence of visual dysfunctions.
METHODS
An optometric examination was conducted in a clinical sample of 346 patients to diagnose any type of visual anomaly. Visual symptoms were collected using the validated SQVD questionnaire. A threshold of 6 hours per day was used to quantify the effects of digital device usage and patients were divided into two groups: under and above of 35 years old. A multivariate logistic regression was employed to investigate the association between digital device use and symptoms, with visual dysfunctions considered as a confounding variable. Crude and the adjusted odds ratio (OR) were calculated for each variable.
RESULTS
57.02 % of the subjects reported visual symptoms, and 65.02% exhibited some form of visual dysfunction. For patients under 35 years old, an association was found between having visual symptoms and digital device use (OR = 2.10, p = 0.01). However, after adjusting for visual dysfunctions, this association disappeared (OR = 1.44, p = 0.27) and the association was instead between symptoms and refractive dysfunction (OR = 6.52, p < 0.001), accommodative (OR = 10.47, p < 0.001), binocular (OR = 6.68, p < 0.001) and accommodative plus binocular dysfunctions (OR = 46.84, p < 0.001). Among patients over 35 years old, no association was found between symptoms and the use of digital devices (OR = 1.27, p = 0.49) but there was an association between symptoms and refractive dysfunction (OR = 3.54, p = 0.001).
CONCLUSIONS
Visual symptoms are not dependent on the duration of digital device use but rather on the presence of any type of visual dysfunction: refractive, accommodative and/or binocular one, which should be diagnosed.
Topics: Humans; Male; Female; Adult; Vision Disorders; Middle Aged; Surveys and Questionnaires; Accommodation, Ocular; Young Adult; Vision, Binocular; Visual Acuity; Adolescent; Aged; Cross-Sectional Studies
PubMed: 38134467
DOI: 10.1016/j.optom.2023.100510 -
Journal of Optometry 2014To determine the symptoms associated with accommodative and non-strabismic binocular dysfunctions and to assess the methods used to obtain the subjects' symptoms. (Review)
Review
PURPOSE
To determine the symptoms associated with accommodative and non-strabismic binocular dysfunctions and to assess the methods used to obtain the subjects' symptoms.
METHODS
We conducted a scoping review of articles published between 1988 and 2012 that analysed any aspect of the symptomatology associated with accommodative and non-strabismic binocular dysfunctions. The literature search was performed in Medline (PubMed), CINAHL, PsycINFO and FRANCIS. A total of 657 articles were identified, and 56 met the inclusion criteria.
RESULTS
We found 267 different ways of naming the symptoms related to these anomalies, which we grouped into 34 symptom categories. Of the 56 studies, 35 employed questionnaires and 21 obtained the symptoms from clinical histories. We found 11 questionnaires, of which only 3 had been validated: the convergence insufficiency symptom survey (CISS V-15) and CIRS parent version, both specific for convergence insufficiency, and the Conlon survey, developed for visual anomalies in general. The most widely used questionnaire (21 studies) was the CISS V-15. Of the 34 categories of symptoms, the most frequently mentioned were: headache, blurred vision, diplopia, visual fatigue, and movement or flicker of words at near vision, which were fundamentally related to near vision and binocular anomalies.
CONCLUSIONS
There is a wide disparity of symptoms related to accommodative and binocular dysfunctions in the scientific literature, most of which are associated with near vision and binocular dysfunctions. The only psychometrically validated questionnaires that we found (n=3) were related to convergence insufficiency and to visual dysfunctions in general and there no specific questionnaires for other anomalies.
Topics: Accommodation, Ocular; Humans; Vision Disorders; Vision, Binocular
PubMed: 25323640
DOI: 10.1016/j.optom.2014.06.005