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Neural Regeneration Research Nov 2023Amblyopia is the most common cause of vision loss in children and can persist into adulthood in the absence of effective intervention. Previous clinical and neuroimaging...
Amblyopia is the most common cause of vision loss in children and can persist into adulthood in the absence of effective intervention. Previous clinical and neuroimaging studies have suggested that the neural mechanisms underlying strabismic amblyopia and anisometropic amblyopia may be different. Therefore, we performed a systematic review of magnetic resonance imaging studies investigating brain alterations in patients with these two subtypes of amblyopia; this study is registered with PROSPERO (registration ID: CRD42022349191). We searched three online databases (PubMed, EMBASE, and Web of Science) from inception to April 1, 2022; 39 studies with 633 patients (324 patients with anisometropic amblyopia and 309 patients with strabismic amblyopia) and 580 healthy controls met the inclusion criteria (e.g., case-control designed, peer-reviewed articles) and were included in this review. These studies highlighted that both strabismic amblyopia and anisometropic amblyopia patients showed reduced activation and distorted topological cortical activated maps in the striate and extrastriate cortices during task-based functional magnetic resonance imaging with spatial-frequency stimulus and retinotopic representations, respectively; these may have arisen from abnormal visual experiences. Compensations for amblyopia that are reflected in enhanced spontaneous brain function have been reported in the early visual cortices in the resting state, as well as reduced functional connectivity in the dorsal pathway and structural connections in the ventral pathway in both anisometropic amblyopia and strabismic amblyopia patients. The shared dysfunction of anisometropic amblyopia and strabismic amblyopia patients, relative to controls, is also characterized by reduced spontaneous brain activity in the oculomotor cortex, mainly involving the frontal and parietal eye fields and the cerebellum; this may underlie the neural mechanisms of fixation instability and anomalous saccades in amblyopia. With regards to specific alterations of the two forms of amblyopia, anisometropic amblyopia patients suffer more microstructural impairments in the precortical pathway than strabismic amblyopia patients, as reflected by diffusion tensor imaging, and more significant dysfunction and structural loss in the ventral pathway. Strabismic amblyopia patients experience more attenuation of activation in the extrastriate cortex than in the striate cortex when compared to anisometropic amblyopia patients. Finally, brain structural magnetic resonance imaging alterations tend to be lateralized in the adult anisometropic amblyopia patients, and the patterns of brain alterations are more limited in amblyopic adults than in children. In conclusion, magnetic resonance imaging studies provide important insights into the brain alterations underlying the pathophysiology of amblyopia and demonstrate common and specific alterations in anisometropic amblyopia and strabismic amblyopia patients; these alterations may improve our understanding of the neural mechanisms underlying amblyopia.
PubMed: 37282452
DOI: 10.4103/1673-5374.371349 -
Eye (London, England) Sep 2023Amblyopia is an important public health concern. While home-based screening may present an effective solution, this has not been rigorously assessed in a systematic... (Review)
Review
Amblyopia is an important public health concern. While home-based screening may present an effective solution, this has not been rigorously assessed in a systematic review. A systematic review was performed using Ovid MEDLINE, PubMed, The Cochrane Library, Embase, Web of Science Core Collection, and Clinicaltrials.gov. All studies reporting the diagnostic accuracy of home-based screening tools for amblyopia among children were included. Studies involving orthoptist or ophthalmologist-led screening and adult subjects were excluded. The main outcome measure was the diagnostic accuracy expressed as sensitivity and specificity. Among 3670 studies identified, 28 were eligible for inclusion in our systematic review. The age range of patients were less than 1 month to 16 years old. 7 studies used internet-based tools, 16 used smartphone/tablet applications, 3 used digital cameras, and 3 used home-based questionnaires and visual acuity tools. All studies included a reference standard except one, which was a longitudinal study. 21 studies had full ophthalmological examination whilst 6 studies had validated visual acuity measurement tools as gold standards. Of the 27 studies which compared against a reference test, only 25 studies reported sensitivity and specificity values. Using the QUADAS-2 tool, 50% of studies were deemed to have applicability concern due to patient selection from tertiary centres and unclear methods for recruitment. There is a need to improve the quality of diagnostic accuracy studies, standardise thresholds for detecting amblyopia, and ensure consistent reporting of results. Further research is needed to evaluate the suitability of these tools for amblyopia screening.
Topics: Adult; Child; Humans; Infant; Amblyopia; Longitudinal Studies; Sensitivity and Specificity; Physical Examination
PubMed: 36828959
DOI: 10.1038/s41433-023-02412-3 -
Pediatric Health, Medicine and... 2023The COVID-19 pandemic came with many new challenges that forced personal and professional lifestyle modifications. Medical facilities were in scarcity against this new... (Review)
Review
The COVID-19 pandemic came with many new challenges that forced personal and professional lifestyle modifications. Medical facilities were in scarcity against this new unknown enemy and were challenged with the overloaded patient flow, scarcity of healthcare staff, and evolving treatment modalities with a better understanding of the virus each day. Ophthalmology as a "branch of medicine" suffered challenges initially because of a lack of guidelines for patient management, close working distance during routine examinations, and halt of major surgeries, including cataracts. Pediatric ophthalmology had major implications, as reduced outpatient visits would mean deeper amblyopia, and changed lifestyles, including online classes and home refinement, predisposing children to myopia, digital eye strain, and worsening of strabismus. COVID-19 also unveiled underlying accommodation and convergence anomalies that predisposed pediatric and adolescent patients to an increased prevalence of headache and acute onset esotropia. Teleophthalmology and other innovative solutions, including the use of prism glasses, safe slit-lamp shields, alternative ways of school screening with the use of photoscreeners, performing retinoscopy only when needed, and using autorefractors were among the few guidelines or modifications adopted which helped in the efficient and safe management of pediatric patients. Many pediatric ophthalmologists also suffered in terms of financial constraints due to loss of salary or even closure of private practices. School screening and retinopathy of prematurity screening suffered a great setback and costed a lot of vision years, data of which remains under-reported. Important implications and learnings from the pandemic to mitigate future similar situations include using teleophthalmology and virtual platforms for the triage of patients, managing non-emergency conditions without physical consultations, and utilizing home-based vision assessment techniques customized for different age groups. Though this pandemic had a lot of negative implications, the innovations, modifications, and other important learnings helped pediatric ophthalmologists in navigating safely.
PubMed: 37849985
DOI: 10.2147/PHMT.S395349 -
Taiwan Journal of Ophthalmology 2023Primary congenital glaucoma (PCG) occurs worldwide and has a broad range of ocular manifestations. It poses a therapeutic challenge to the ophthalmologist. A proper... (Review)
Review
Primary congenital glaucoma (PCG) occurs worldwide and has a broad range of ocular manifestations. It poses a therapeutic challenge to the ophthalmologist. A proper diagnostic evaluation under anesthesia is advisable for all children who do not cooperate for an office examination. Medical therapy only serves as a supportive role, and surgical intervention remains the principal therapeutic modality. Angle incision surgery such as goniotomy or trabeculotomy ab externo is the preferred choice of surgery in the Caucasian population. Primary combined trabeculotomy-trabeculectomy with or without antifibrotic therapy is the preferred choice in certain regions such as India and the Middle East where the disease usually presents with severe forms of corneal edema along with megalocornea. In refractory cases, trabeculectomy with antifibrotic therapy or glaucoma drainage devices are available options in the armamentarium. Cycloablative procedures should be reserved for eyes with poor visual potential. Myopia is common among children with PCG, and appropriate optical refractive correction in the form of glasses or contact lenses should be provided. Amblyopia therapy should be instituted to ensure overall visual development in the early developmental years. Low-vision rehabilitation services should be provided to children with vision impairment. Long-term follow-up is mandatory and carers of children with PCG should be counseled and educated about this need. Regardless of the visual outcomes, clinicians should emphasize the need for education of these children during the clinic visit. The overall goal of the management should be to improve the overall quality of life of the children with PCG and their carers.
PubMed: 38249492
DOI: 10.4103/tjo.TJO-D-23-00104 -
International Ophthalmology Feb 2024Pediatric keratoconus (pediatric KC) causes progressive deformation of the cornea in children and adolescents, leading to a gradual loss of vision and a need for... (Review)
Review
BACKGROUND
Pediatric keratoconus (pediatric KC) causes progressive deformation of the cornea in children and adolescents, leading to a gradual loss of vision and a need for rehabilitation. However, new treatments may halt the disease and prevent worse outcomes that require penetrating keratoplasty and its associated morbidity and high cost, irreversible loss of vision, and amblyopia. Few systematic reviews focus on keratoconus-and even fewer, on pediatric KC.
METHODS
Here, we report a systematic scoping review of pediatric KC epidemiology and discuss the studies reporting data on pediatric KC. We used PRISMA-ScR methodology and checklists in the elaboration of the manuscript. The inclusion criteria were: English language; publication between August 7, 1998, and August 7, 2019 (20 years); theme of the study pediatric KC epidemiology. The search strategy: searches of the PubMed-MEDLINE database and Cochrane Database of Systematic Reviews, using eight combinations of the following MeSH terms: keratoconus; child; incidence; prevalence; pediatrics; adolescent; epidemiology.
RESULTS
We charted and reviewed the selected articles. Initial searches included 1802 records; after the exclusion of article duplicates, we screened 777 records, read 97 articles in full text, and included 76 articles in this review.
CONCLUSIONS
Recent epidemiological studies with better methodologies demonstrated increased prevalence rates in comparison to the older literature. This effect may be due to better diagnostic methods and better sample selection than those in historical studies. Diagnosis remains a major challenge as the early disease is usually asymptomatic. Economic and social aspects of pediatric KC remain understudied in the pediatric literature. Global, inclusive, and proactive screening studies in schools are imperative to better understand the great impact of this disease in the young.
Topics: Adolescent; Humans; Child; Keratoconus; Cornea; Keratoplasty, Penetrating; Morbidity; Incidence
PubMed: 38347389
DOI: 10.1007/s10792-024-03010-2 -
Clinical & Experimental Optometry Sep 2023Understanding the refractive profile, amblyopia prevalence, binocular status, and head position in patients with Brown syndrome help clinicians become more familiar with...
CLINICAL SIGNIFICANCE
Understanding the refractive profile, amblyopia prevalence, binocular status, and head position in patients with Brown syndrome help clinicians become more familiar with this syndrome.
BACKGROUND
Brown syndrome is identified as an active and passive restricted elevation of the eye in adduction. There is little information on clinical features, including refractive status, amblyopia, abnormal head posture (AHP), and types of deviation in these patients.
METHODS
This study retrospectively evaluated records of 100 Brown syndrome patients from 2015 to 2022 at Farabi Eye Hospital, Iran.
RESULTS
The mean age was 6.99 ± 6.33 years, including 48 (48%) males. A congenital source was found in 74 (74%) and 96 (96%) patients had unilateral involvement. The mean CDVA for the affected and non-affected eyes were 0.05 ± 0.11 and 0.03 ± 0.06 logMAR, respectively ( = 0.31). In unilateral cases, hyperopia, myopia, and emmetropia were observed in 55 (57.29%), 2 (2.08%), and 39 (40.63%) affected eyes, respectively. The most common type of deviation was pure hypotropia, which was found in 53 (53%) cases, followed by 'combined exotropia and hypotropia' observed in 26 (26%) patients. The mean angle of hypotropia and horizontal deviation in the primary position at distance was 12.10 ± 8.50 and 8 ± 13.20 prism dioptre, respectively. A V-pattern was found in 76 (76%) patients. Amblyopia was observed in 13 (21.67%) of 60 cooperative patients, and AHP was noticed in 66 (66%) patients, in which "combined chin up and contralateral face turn" was the most common type.
CONCLUSION
About 75% of cases were congenital, 50% had pure hypotropia, 75% showed V-pattern, 20% had amblyopia, and AHP was observed in 67% of patients. The remarkable prevalence of amblyopia alongside the high occurrence of AHP should alert clinicians to carefully assess patients with Brown syndrome for sensory fusion and amblyopia.
PubMed: 37759378
DOI: 10.1080/08164622.2023.2256323 -
BMC Ophthalmology Jun 2024The long-term visual outcomes in spasmus nutans patients is largely unknown. The purpose of this study was to characterize visual outcomes and identify comorbid...
BACKGROUND
The long-term visual outcomes in spasmus nutans patients is largely unknown. The purpose of this study was to characterize visual outcomes and identify comorbid ophthalmic conditions in patients with spasmus nutans.
METHODS
We retrospectively reviewed the charts of consecutive patients diagnosed with spasmus nutans between 2000 and 2020. Demographic information, ophthalmic characteristics, and neuroimaging results were assessed over time.
RESULTS
Of the 32 patients included in the study, 13 (41%) were female. Underlying medical conditions included a diagnosis of Trisomy 21 in 6 (19%) and prematurity in 8 (25%). Twenty-one patients (66%) self-reported as a race other than Caucasian. 18 patients (56%) had non-private health insurance and 1 (3%) was uninsured. Mean age at diagnosis and resolution were 16 months (range 45 months) and 48 months (range 114 months), respectively. All 32 patients had nystagmus, 31 (97%) had head nodding and 16 (50%) had ocular torticollis. Mean follow-up was 66 months (range 185 months). On initial presentation, 6/32 (19%) had an amblyogenic refractive error and mean best-corrected visual acuity (BCVA) in the better-seeing eye was 0.78 Logarithm of the Minimum Angle of Resolution (LogMAR) (range 1.24). In a sub-analysis that included patients with > 1 exam (n = 23), 17/20 (85%) had an amblyogenic refractive error and mean BCVA in the better-seeing eye was 0.48 LogMAR (range 1.70). At the final exam, 12 patients had measurable stereopsis, eight had strabismus, and three had undergone strabismus surgery. Eight patients required treatment for amblyopia.
CONCLUSIONS
We found a high prevalence of amblyogenic refractive error, strabismus and amblyopia among patients with spasmus nutans. Children with spasmus nutans benefit from ongoing ophthalmic follow-up until they are past the amblyopic age range, even after resolution of nystagmus.
Topics: Humans; Female; Male; Retrospective Studies; Visual Acuity; Child, Preschool; Child; Infant; Follow-Up Studies; Nystagmus, Pathologic; Amblyopia; Strabismus
PubMed: 38867186
DOI: 10.1186/s12886-024-03494-7 -
Oman Journal of Ophthalmology 2024
PubMed: 38524343
DOI: 10.4103/ojo.ojo_28_24 -
Frontiers in Neuroscience 2023Amblyopia is a common visual impairment that develops during the early years of postnatal life. It emerges as a sequela to eye misalignment, an imbalanced refractive...
Amblyopia is a common visual impairment that develops during the early years of postnatal life. It emerges as a sequela to eye misalignment, an imbalanced refractive state, or obstruction to form vision. All of these conditions prevent normal vision and derail the typical development of neural connections within the visual system. Among the subtypes of amblyopia, the most debilitating and recalcitrant to treatment is deprivation amblyopia. Nevertheless, human studies focused on advancing the standard of care for amblyopia have largely avoided recruitment of patients with this rare but severe impairment subtype. In this review, we delineate characteristics of deprivation amblyopia and underscore the critical need for new and more effective therapy. Animal models offer a unique opportunity to address this unmet need by enabling the development of unconventional and potent amblyopia therapies that cannot be pioneered in humans. Insights derived from studies using animal models are discussed as potential therapeutic innovations for the remediation of deprivation amblyopia. Retinal inactivation is highlighted as an emerging therapy that exhibits efficacy against the effects of monocular deprivation at ages when conventional therapy is ineffective, and recovery occurs without apparent detriment to the treated eye.
PubMed: 37795183
DOI: 10.3389/fnins.2023.1249466