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Journal of the Neurological Sciences Nov 2022Reading is a vision-reliant task, requiring sequential eye movements. Binocularly discordant input results in visual sensory and oculomotor dysfunction in amblyopia,...
INTRODUCTION
Reading is a vision-reliant task, requiring sequential eye movements. Binocularly discordant input results in visual sensory and oculomotor dysfunction in amblyopia, which may contribute to reading difficulties. This study aims to determine the contributions of fixation eye movement (FEM) abnormalities, clinical type and severity of amblyopia to reading performance under binocular and monocular viewing conditions.
METHODS
Twenty-three amblyopic patients and nine healthy controls were recruited. Eye movements elicited during fixation and reading of preselected passages were collected for each subject using infrared video-oculography. Subjects were classified as having no nystagmus (n = 9), fusion maldevelopment nystagmus (FMN, n = 5), or nystagmus without structural anomalies that does not meet criteria for FMN or infantile nystagmus (n = 9). Reading rate (words/min), the number of forward and regressive saccades (per 100 words) and fixation duration (s) were computed.
RESULTS
Amblyopic patients with and without nystagmus exhibited greater vergence and fixation instability. In patients without nystagmus, the instability arises from increased amplitude and velocity of fast and slow FEMs respectively. Amblyopic patients with and without nystagmus exhibited lower reading speeds with increased fixation duration, regressive and progressive saccades than controls in all viewing conditions. Mixed etiology, greater amblyopic eye visual acuity and stereopsis deficits were associated with greater reading difficulties under binocular viewing.
CONCLUSIONS
The presence of oculomotor dysfunction and the extent of visual acuity and stereoacuity deficits contribute to reading difficulties in patients with amblyopia, with and without nystagmus. The understanding of reading difficulties is essential to devise accommodations to limit long-term academic and vocational consequences of amblyopia.
Topics: Humans; Amblyopia; Dyslexia; Eye Movements; Nystagmus, Pathologic; Ocular Motility Disorders; Saccades
PubMed: 36242809
DOI: 10.1016/j.jns.2022.120438 -
Ophthalmic Research 2023Amblyopia is a common cause of visual disorder with several changes in retinal structure and vessel. To date, alterations in retinal microvasculature features in... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Amblyopia is a common cause of visual disorder with several changes in retinal structure and vessel. To date, alterations in retinal microvasculature features in amblyopia have yielded inconsistent results.
OBJECTIVES
This meta-analysis aimed to evaluate retinal vessel density (VD) in amblyopic patients using optical coherence tomography angiography (OCTA).
METHODS
PubMed, Web of Science, Embase, and Cochrane Library databases were systematically searched for published articles comparing retinal microvasculature characteristics in patients with amblyopia and controls. Continuous variable outcomes were assessed using the mean difference (MD) with a 95% confidence interval. Review Manager Version 5.30 was used for the analysis.
RESULTS
Thirteen qualified articles were pooled in this meta-analysis. Compared with controls, the foveal whole en face VD of superficial capillary plexus (SCP) and deep capillary plexus (DCP) of patients as measured by 3 × 3-mm scans were significantly lower in amblyopia eyes (MD: -1.37, p = 0.0003; MD: 1.70, p < 0.00001, respectively). Similarly, in the 6 × 6-mm scans, foveal whole en face VD of the SCP and DCP were remarkably lower in amblyopia eyes than in controls (MD: -2.24, p = 0.03; MD: -5.08, p = 0.04, respectively). The parafoveal VD of SCP in 3 × 3-mm scans (MD: -1.96, p < 0.00001) was also lower in amblyopic patients than in controls. Similarly, in 6 × 6-mm scans, amblyopia eyes showed a significant decrease and a trending decrease in the parafoveal VD of the SCP (MD: -3.85, p = 0.007) and DCP (MD: -3.03, p = 0.10), respectively. For whole radial peripapillary capillary (RPC), VD was significantly reduced in amblyopic patients compared to controls (MD = -0.83, p < 0.00001). In addition, the deep foveal avascular zone (FAZ) was larger in amblyopic eyes than in the controls (MD = 0.55, p = 0.007).
CONCLUSIONS
Our data suggest that whole foveal and parafoveal VD and RPC whole VD were reduced in patients with amblyopia. Moreover, our results reveal that the FAZ is larger in amblyopic patients. Consequently, OCTA may have the potential for diagnosing and monitoring patients with amblyopia.
Topics: Humans; Amblyopia; Fluorescein Angiography; Cross-Sectional Studies; Retina; Retinal Vessels; Microvessels; Tomography, Optical Coherence
PubMed: 35998587
DOI: 10.1159/000526531 -
Medicina (Kaunas, Lithuania) Dec 2023: Amblyopia is a neurodevelopmental disorder caused by interocular suppression of visual input, affecting visual acuity, stereopsis, contrast sensitivity, and other... (Review)
Review
: Amblyopia is a neurodevelopmental disorder caused by interocular suppression of visual input, affecting visual acuity, stereopsis, contrast sensitivity, and other visual functions. Conventional treatment comprises occlusion of the sound eye. In recent years, novel therapies that deploy perceptual learning (PL) principles have been introduced. The purpose of this study is to assess the latest scientific data on this topic. : For this purpose, we conducted a literature search for relevant studies published during the previous 4 years (2020-2023). : A plethora of visual perceptual learning protocols have been recently developed. Dichoptic video games, contrast rebalanced movies, and online perceptual training platforms are the main formats. Perceptual learning activates neuroplasticity, overcomes interocular suppression, and improves the visual impairments induced by amblyopia. This novel treatment is effective in both children and adults, as well as in patients non-responding to patching.
Topics: Adult; Child; Humans; Amblyopia; Visual Acuity; Spatial Learning; Neurodevelopmental Disorders; Neuronal Plasticity
PubMed: 38256309
DOI: 10.3390/medicina60010048 -
Strabismus Mar 2022Despite internationally recognized guidelines, amblyopia management varies among eye care professionals worldwide. Hence, we sought to investigate the practice patterns...
Despite internationally recognized guidelines, amblyopia management varies among eye care professionals worldwide. Hence, we sought to investigate the practice patterns of amblyopia management and the factors associated with the decision to treat amblyopia among optometrists in Ghana. A cross-sectional survey was conducted among registered optometrists in Ghana from January 2020 to October 2020. Data collection was done through the administration of online questionnaires via e-mail (google form). The structured questionnaires included demographic information, mode, and scope of practice, diagnostic criteria, examination procedures, treatment modalities, and prognosis. A p value of less than 0.05 was deemed statistically significant. The mean (±SD) age of all the 168 respondents was 32.6 (±6.1) years (range: 24-50 years). The majority of the optometrists (64.9%) treated amblyopia in their practice; with the most prevalent being refractive amblyopia (68.2%), followed by strabismic amblyopia (27.1%), then form-deprivation amblyopia (4.7%). Most (76.1%) amblyopic patients presented with symptomatic squinting. The most common ocular and medical history was anisometropia (90.0%), and the most common diagnostic procedures were patient history, visual acuity, and refraction. Optical correction (88.3%) was mainly prescribed for amblyopia treatment, followed by patching (58.5%). Nearly half of the respondent (45.0%) reported good prognosis after amblyopia treatment. After statistical adjustment, female optometrists were significantly associated with decreased odds of treating amblyopia (AOR = 0.36, p = .004). Refractive amblyopia is the main type of amblyopia managed by optometrists in Ghana. Hence, optical correction is the primary treatment regime. Current amblyopia management practice among optometrists adhere to recommended guidelines and our findings demonstrate uniformity in the standard of care.
Topics: Adult; Amblyopia; Anisometropia; Cross-Sectional Studies; Female; Ghana; Humans; Middle Aged; Optometrists; Strabismus; Young Adult
PubMed: 35023425
DOI: 10.1080/09273972.2021.2022715 -
Strabismus Mar 2021To determine the prevalence of amblyopia and its determinants in underserved rural villages of Iran. This population-based cross-sectional study was conducted in 3850...
To determine the prevalence of amblyopia and its determinants in underserved rural villages of Iran. This population-based cross-sectional study was conducted in 3850 subjects selected from two underserved districts in the north (Kojur District, Nowshahr County, Mazandaran Province) and southwest (Shahyun District, Dezful County, Khuzestan Province) of Iran using multi-stage cluster sampling. The subjects underwent complete ophthalmic examinations including the measurement of uncorrected (UCVA) and best-corrected (BCVA) visual acuity, objective and subjective refraction, unilateral and alternate cover tests and ocular health examination. Amblyopia was defined as a reduction of BCVA to 20/30 or less in one eye or a 2-line interocular optotype acuity difference in the absence of any pathological factors. Of 3850 selected subjects, 3314 participated in the study (response rate = 86.08%). The mean age of the participants was 36.90 ± 20.21 years (range: 3-93 years). The prevalence and 95% confidence interval of total, bilateral, and unilateral amblyopia were 2.73% (2.17 to 3.38), 0.50% (0.28 to 0.83), and 2.23% (1.73 to 2.83), respectively. The most common type of amblyopia was anisometropic followed by strabismic and mixed. The lowest and highest prevalence was seen in the age group 6-20 years (1.36%; 0.65 to 2.49) and above 70 years (5.97%; 3.02 to 10.44), respectively. According to the results of multiple logistic regression analysis, compared to illiterate subjects, the odds ratio of amblyopia was 0.321 ( = .033) in subjects with High school education, 0.181 ( = .030) in subjects with secondary School education, and 0.486 ( = .041) in subjects with primary school education. The odds ratio of amblyopia for north villages residence vs southwest villages residence was 2.105 ( = .012). The odds ratio of amblyopia was 2.765 for age group>70 years vs. 6-20 years ( = .033). The prevalence of amblyopia was higher in north region, in participants with lower education level and older individuals. The high prevalence of amblyopia in older people may be due to the lack of screening programs in previous generations and consequently the lack of timely diagnosis and treatment.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Amblyopia; Child; Child, Preschool; Cross-Sectional Studies; Humans; Middle Aged; Prevalence; Rural Population; Strabismus; Young Adult
PubMed: 33455499
DOI: 10.1080/09273972.2020.1871375 -
Journal of Visualized Experiments : JoVE Jan 2020Conventional amblyopia therapy involves occlusion or penalization of the dominant eye, though these methods enhance stereoscopic visual acuity in fewer than 30% of...
Conventional amblyopia therapy involves occlusion or penalization of the dominant eye, though these methods enhance stereoscopic visual acuity in fewer than 30% of cases. To improve these results, we propose a treatment in the form of a video game, using random-dot stimuli and perceptual learning techniques to stimulate stereoacuity. The protocol is defined for stereo-deficient patients between 7-14 years of age who have already received treatment for amblyopia and have a monocular best corrected distance visual acuity of at least 0.1 logMAR. Patients are required to complete a perceptual learning program at home using the video game. While compliance is stored automatically in the cloud, periodic optometry center visits are used to track patient evolution and adjust the game's stereoscopic demand until the smallest detectable disparity is achieved. The protocol has proved to be successful, and effectiveness is gauged in terms of a two-level gain on a random stereoacuity test (global stereoacuity or cyclopean stereoacuity reference test). Moreover, the random-dot stimuli learning transfers to medial lateral stereoscopic acuity according to a Wirt Circles test, in which success criteria is a final stereoacuity of over 140", and the attained enhancement corresponds to no less than two levels of stereoscopic acuity. Six months later, a random-dot stereoacuity test recorded no reduction in the stereoacuity that was achieved.
Topics: Adolescent; Amblyopia; Child; Female; Humans; Male; Video Games; Visual Acuity
PubMed: 32009644
DOI: 10.3791/60236 -
Strabismus Jun 2022This study aimed to calculate the dose-response relationship and predictors of visual acuity (VA) improvement following occlusion therapy at the IWK Health Center Eye...
This study aimed to calculate the dose-response relationship and predictors of visual acuity (VA) improvement following occlusion therapy at the IWK Health Center Eye Clinic and to add to amblyopia therapy dose-response relationship literature. A retrospective chart review was performed, considering patients who reached an occlusion therapy outcome at the IWK Eye Clinic between 2012 and 2019. The treatment outcome was defined as equal VA or stable VA for three consecutive clinical visits despite reported compliance. Subjective patching hours from parental reports, not prescribed hours, were used for statistical analyses. One hundred and thirty-four patients (66 females and 68 males) ages 2-11 years were included. Results showed a dose-response relationship of 224 hours/0.1logMAR increase in VA and total dose of 1344 hours for full-time occlusion and 504 hours for part-time occlusion was required to reach outcome VA. The fastest VA improvement occurred with younger age at treatment initiation, during the first 4 weeks of treatment, and in patients with strabismic and/or severe amblyopia. Classification of amblyopia, age, VA chart, initial distance VA (amblyopic eye), and treatment dose predicted the hour dose-response relationship. Dose-response relationship was faster in younger participants, in participants with strabismic and severe amblyopia, and during the first month of occlusion. Additionally, by creating a GLM model of dose-response relationship, relationship calculations can be performed. Therefore, an estimated timeline can be developed to allow allocation of clinical resources and to prepare patients for the treatment duration required and possibly increase treatment compliance.
Topics: Amblyopia; Child; Child, Preschool; Female; Humans; Male; Retrospective Studies; Sensory Deprivation; Treatment Outcome; Visual Acuity
PubMed: 35259060
DOI: 10.1080/09273972.2022.2046114 -
Journal of AAPOS : the Official... Oct 2023To compare amblyopia treatment outcomes between patients with neurodevelopmental disorders and their typically developing peers.
PURPOSE
To compare amblyopia treatment outcomes between patients with neurodevelopmental disorders and their typically developing peers.
METHODS
Of 2,311 patients diagnosed with amblyopia between 2010 and 2014 at Boston Children's Hospital, 460 met inclusion criteria (age 2-12 with anisometropic, strabismic, or mixed amblyopia [interocular difference (IOD) ≥2 lines]). Treatment and visual outcomes were analyzed according to neurodevelopmental status: neurodevelopmental delay (DD) versus typical development (TD).
RESULTS
The DD group (n = 54) and TD group (n = 406) were similar in demographics, amblyogenic risk factors, baseline visual measures, prescribed therapy, and adherence (P ≥ 0.10). Between-visit follow-up time was longer for the DD group (0.65 [0.42- 0.97] years) than for the TD group (0.5 [0.36-0.82] years; P = 0.023). IOD improved similarly in each group by the last visit (DD, -0.15 logMAR [-0.31 to -0.02]; TD, -0.2 logMAR [-0.38 to -0.1]; P = 0.09). Each group reached amblyopia resolution by the last visit at similar frequencies (DD, 23/54 [43%]; TD, 211/406 [52%]; P > 0.2). DD diagnosis did not independently influence amblyopia resolution (HR, 0.77; 95% CI, 0.53-1.12; P = 0.17), but each additional month of interval time between follow-up visits reduced the likelihood of resolution by 2.7% (HR, 0.67; 95% CI, 0.51-0.87; P = 0.003).
CONCLUSIONS
Patients with DD and those with TD responded similarly to amblyopia therapy; however, follow-up intervals were longer in patients with DD and correlated with the likelihood of persistent amblyopia, suggesting that greater efforts at assuring follow-up may benefit patients with DD.
Topics: Child; Humans; Child, Preschool; Amblyopia; Visual Acuity; Treatment Outcome; Risk Factors; Neurodevelopmental Disorders; Sensory Deprivation; Follow-Up Studies
PubMed: 37739211
DOI: 10.1016/j.jaapos.2023.07.014 -
Strabismus Sep 2020Amblyopia is a developmental ocular disease of childhood-onset which may lead to persistent sequelae into adulthood. Early detection and management of amblyopia usually...
Amblyopia is a developmental ocular disease of childhood-onset which may lead to persistent sequelae into adulthood. Early detection and management of amblyopia usually result in an improved visual outcome. The purpose of this study was to determine the prevalence and pattern of amblyopia in a rural hospital in Ghana. Clinical records of patients seen (from January 2014 to December 2018) at Westphalian Medical Center, Oyoko, Ashanti Region, Ghana, were reviewed retrospectively. Unilateral amblyopia was defined as a two-line interocular difference or more in visual acuity. Bilateral amblyopia was defined as best-corrected visual acuity (BCVA) of Snellen 6/12 or worse in both eyes, with evidence of bilateral ametropia or obstruction of the visual pathway. Following a review of 12,602 patient records, 258 cases of amblyopia were identified. The mean (±SD) presenting age of amblyopic patients was 24.3 ± 16.1 years, with a male-to-female ratio of 1:1.1. The period prevalence of amblyopia was 2.04%. The period prevalence of unilateral and bilateral amblyopia was 1.38% and 0.66%, respectively. The most prevalent form of amblyopia was refractive with a cumulative prevalence of 1.42%. Strabismic and stimulus deprivation amblyopia accounted for 0.36% and 0.21% of all amblyopic cases, respectively. A major cause of amblyopia in this population was refractive error, hence the use of spectacle correction for its initial management. Repeated assessment after an appropriate period of refractive adaptation would elucidate the proportion of amblyopias needing additional treatment modalities. Vision screening for early detection of amblyopia in childhood with accessible and effective management of amblyopia (including refractive correction and occlusion treatment) is necessary to reduce the impact of amblyopia in Ghana.
Topics: Adolescent; Adult; Aged; Amblyopia; Child; Child, Preschool; Female; Ghana; Hospitals, Rural; Humans; Infant; Male; Middle Aged; Prevalence; Refractive Errors; Retrospective Studies; Strabismus; Vision Screening; Visual Acuity; Young Adult
PubMed: 32627626
DOI: 10.1080/09273972.2020.1779319 -
FP Essentials Sep 2019Amblyopia is a developmental disorder of the central nervous system. It occurs in infancy or early childhood when the visual system is susceptible to issues that...
Amblyopia is a developmental disorder of the central nervous system. It occurs in infancy or early childhood when the visual system is susceptible to issues that interrupt development. In the United States, up to 2% of infants and children ages 6 to 71 months have amblyopia. Risk factors for amblyopia include hyperopia, astigmatism, and myopia. Risk factors are more common in children who are premature or small for gestational age. Management of amblyopia in children includes optical correction of refractive errors, occlusion therapy (patching), pharmacotherapy, and surgery. Strabismus occurs when one eye can focus on an object or a point but the other eye turns inward toward the nose (esotropia), upward (hypertropia), downward (hypotropia), or outward toward the temple (exotropia). The patient may report diplopia or vision loss and may present with compensating posture such as a head tilt. Nonsurgical (ie, eyeglasses, prisms, onabotulinumtoxinA) and surgical management options are available to manage strabismus.
Topics: Amblyopia; Child; Child, Preschool; Eyeglasses; Humans; Infant; Refractive Errors; Strabismus; United States; Visual Acuity
PubMed: 31454213
DOI: No ID Found