The Global Prevalence of Amblyopia in Children: A Systematic Review and Meta-Analysis

Sustainable and biotechnological production of docosahexaenoic acid from marine protists and slaughterhouse waste

Docosahexaenoic acid (DHA, 22:6n-3) is an essential omega-3 polyunsaturated fatty acid, abundant in the brain and eyes. DHA is crucial for maintaining the structural integrity and physiological functions of these vital organs. Within the brain, DHA is concentrated in the gray matter, synaptic membranes, and hippocampus. Likewise, in the eyes, substantial quantities can be found in the retina, with lower levels in the cornea and lens. Previous studies have outlined the potential for culturing marine heterotrophic protists in ways that provide cost-effective and sustainable DHA biosynthesis. Similarly, our previous work on repurposing slaughterhouse waste has highlighted this underutilized source of brain and ocular tissue, which can support the extraction of valuable nutrients such as DHA. In this review, we will examine the current state of the art related to DHA production from these two sources, explore potential applications, and outline the possible benefits that may be generated from our approaches, with an emphasis on ocular diseases.

Successful persistent strabismic amblyopia treatment using active therapy as an adjuvant to occlusion

PURPOSE

A novel protocol to improve long-term results in the treatment of amblyopia was proposed. The protocol combines active home-based therapy through perceptual learning activities (Gabor patch, dichoptic stimulation, and random dot stereograms) with conventional visual therapy in the clinic as an adjunct to patching occlusion in subjects with patch-resistant amblyopia METHODS: Between 2018 and 2022, a group of patients received treatment for persistent strabismic and combined-mechanism amblyopia according to the novel treatment protocol, consisting of in-clinic orthoptics/visual therapy combined with the use of gamified PL software at home, as an adjunct to occlusion treatment.

RESULTS

A retrospective analysis of treatment outcomes was subsequently carried out for 53 patients aged 7.75±5.88. Eccentric fixation was present in 17 of the 53 subjects. The distribution of patients presenting with combined-mechanism and strabismic amblyopia was 37 and 16, respectively. Eighteen patients (34 %) demonstrated measurable stereoacuity prior to treatment. Following treatment using the combined treatment protocol, forty-six (87 %) participants achieved a of logMAR 0.1 or better, mean BCVA was significantly improved, from logMAR 0.30±0.23 to logMAR 0.07±0.12 (p < 0.01). Eleven subjects (65 %) of seventeen participants with eccentric fixation achieved central fixation. In addition, stereoacuity was measurable in 43 patients (81 %). Mean stereoacuity improved, from 1200.00±258.69 arc seconds to 539.62±518.69 arc seconds (p < 0.01). These results remained stable six months after completion of the therapy.

CONCLUSION

The outcomes of the proposed novel treatment protocol were reduced angle of deviation, and improved BCVA and stereoacuity in patients with persistent strabismic and combined-mechanism amblyopia.

Association between suppression scotoma and visual acuity in clinical subgroups of amblyopia: a systematic review protocol

OBJECTIVE

This review will examine the association between suppression scotoma and visual acuity in clinical subgroups of amblyopia in humans to determine whether distinct causal factors of amblyopia lead to different suppression characteristics and their association with visual acuity.

INTRODUCTION

Amblyopia is a neurodevelopmental disorder that impairs visual acuity, stereo acuity, and contrast sensitivity in 1 or both eyes due to physiological alterations in the visual pathways. Numerous studies have examined the association between amblyopia and suppression. However, the relationship between suppression size, depth, and visual acuity in amblyopia remains unclear.

INCLUSION CRITERIA

This review will include randomized controlled trials, cohort studies, case-control studies, and cross-sectional studies, with participants of any age or gender, diagnosed with amblyopia and with outcome measures of visual acuity (in LogMAR or Snellen's fraction), suppression size (degree of visual angle), and suppression depth (contrast difference in dichoptic targets).

METHODS

This review will follow the JBI methodology for systematic reviews of etiology and risk. Academic and non-academic databases and gray literature will be searched, including MEDLINE (Ovid), Embase (Ovid), Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science Core Collection, ProQuest Health and Medical Collection, and Google Scholar. Titles and abstracts, and later, full texts of included studies will be screened by 2 independent reviewers. Critical appraisal will be conducted using JBI checklists. Where possible, the studies will be pooled using random effects meta-analysis. If statistical pooling is not possible, the findings will be presented in narrative format, including tables and figures. Certainty of the evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach.

REVIEW REGISTRATION

PROSPERO CRD42023479043.

Association of albumin-bilirubin grade with survival outcomes in patients with cholangiocarcinoma

BACKGROUND

Numerous studies have reported the association between preoperative albumin-bilirubin (ALBI) grade and survival outcomes in patients with cholangiocarcinoma (CCA). However, the results are inconsistent. Therefore, we conducted a meta-analysis to comprehensively evaluate the relationship between ALBI grade and prognosis of CCA patients.

METHODS

We retrieved the databases (Pubmed,Embase and Web of science) to search articles about the association of ALBI grade with prognostic value in CCA patients. Hazard ratios (HR) and 95% confidence intervals (CI) were used to summarize survival outcomes. STATA 12.0 was used to implement the data analyses.

RESULTS

11 studies from 10 articles comprising 2841 patients were included in the meta-analysis. The pooled results showed that high ALBI grade was significantly associated with poor overall survival (OS) (HR: 1.75, 95% CI: 1.32-2.31) and relapse-free survival(RFS)(HR:1.95;95%CI:1.37-2.13). Subgroup analysis further showed that high ALBI grade had better predictive value for Asian population(HR:1.92;95%CI:1.46-2.51). Sensitivity analysis indicated that the results of the meta-analysis were stable.

CONCLUSIONS

High ALBI grade predicted adverse survival outcomes in CCA patients. ALBI grade may be an efficient and convenient prognostic indicator in CCA patients for Asian population.

Visual Outcomes after Strabismus Surgery in Pediatric Patients with Strabismic Amblyopia: An IRIS® Registry Study

PURPOSE

To evaluate the impact of strabismus surgery on visual outcomes in pediatric patients with strabismic amblyopia.

DESIGN

Retrospective analysis of the American Academy of Ophthalmology IRIS® Registry (Intelligent Research in Sight).

PARTICIPANTS

Pediatric patients aged 3 to 17 with strabismus and amblyopia.

METHODS

Visual acuity (VA) was assessed at 6, 12, and 24 months post amblyopia diagnosis. Patients were categorized based on age (3-7, 8-12, 13-17 years) and whether they had strabismus surgery before or within 6 months of amblyopia diagnosis. Propensity score matching (PSM) was used to pair the patients who performed strabismus surgery with patients who did not.

MAIN OUTCOME MEASURES

VA changes and treatment efficacy, assessed using the modified IRIS-50 outcome measure.

RESULTS

Of the 21,242 patients analyzed, 1,703 underwent surgery within 6 months of amblyopia diagnosis and 19,539 did not. In PSM cohort, among patients with baseline VA worse than 20/30, visual acuity significantly improved over time in both the strabismus surgery and no strabismus surgery groups. Overall, VA improved from 0.46 ± 0.21 logMAR at baseline to 0.29 ± 0.24 logMAR at 24 months (P < 0.001), with significant improvements observed in both groups at each follow-up (6, 12, and 24 months). Improvement was most pronounced in the youngest group (ages 3-7 years), while teenage patients (ages 13-17 years) showed no improvement. There were no significant differences in visual outcomes between patients who had strabismus surgery and those who did not at any time point. In multivariable logistic regression, there was no difference in the odds of treatment success, as measured by IRIS-50, at the final follow-up between patients who underwent strabismus surgery and those who did not. This was true in all age categories.

CONCLUSIONS

Strabismus surgery did not significantly impact visual outcomes in patients with strabismic amblyopia. Older patients, up to at least age 12, may still have visual benefits from both strabismus surgery and amblyopia treatment.

Prevalence, Causes, and Risk Factors Associated with Visual Impairment in Qbah, a Rural Community in the Qassim Region of Saudi Arabia

BACKGROUND

Visual impairment can significantly impact an individual's performance, productivity, and overall quality of life.

OBJECTIVES

The objective of this paper is to report the prevalence, causes, and risk factors associated with visual impairment in Qbah, a rural community in the Qassim Province of Saudi Arabia.

METHODS

A descriptive cross-sectional study was conducted in Qbah, a rural community, with 587 subjects aged 6 to 80 years. Data were collected as part of a major campaign by Qassim University, and each participant underwent a comprehensive eye examination. Finally, the visual impairment was classified based on the International Classification of Diseases 11th revision, 2018 (ICD-11).

RESULTS

The overall prevalence of presenting visual impairment was 159 (27.1%). This included mild visual impairment 84 (14.37%), moderate visual impairment 65 (11.7%), severe visual impairment, and blindness 5 (0.90%). The main causes of visual impairment were uncorrected refractive errors (UREs), at 132 (83.0%), followed by amblyopia, at 14 (8.8%), and cataract, at 9 (5.7%). The prevalence of hyperopia, myopia, and astigmatism was 134 (22.8%), 174 (29.6%), and 13 (2.2%), respectively. Regression analysis revealed that the odds for visual impairment were 2.71 times higher in the elderly compared to the young participants. Women have 2.234 times higher odds of visual impairment compared to men, while the odds of visual impairment were 14.83 times higher in the participants with the URE compared to the emmetropic participants. Almost two-thirds of participants (65.8%) reported never having had an eye examination before.

CONCLUSIONS

Visual impairment was common in the community, especially among older people and females, and URE was the main cause of visual impairment, followed by amblyopia and cataract. Considerable subjects reported never having had an eye examination before; this highlights the challenges in accessing healthcare in rural areas. These findings emphasize the importance of improving healthcare accessibility in rural regions.

Occlusion Outcomes in Unilateral Amblyopia Types: A Longitudinal and Interventional Study in Children from the Marrakech-Safi Region

Objective

To investigate if the type of unilateral amblyopia can impact the improvement of visual acuity in amblyopic eyes during a longitudinal interventional study involving standard occlusion therapy in children.

Methods

A longitudinal and interventional study of 91 children, aged 3-9 years (6.12 ± 1.879) with amblyopia was undertaken. Amblyopia was unilateral and caused by either strabismus, anisometropia, or both. Amblyopia was divided into three levels of severity mild, moderate, and severe. Children underwent amblyopia treatment with standard occlusion therapy and were followed monthly, for eight visits.

Results

A significant improvement in visual acuity was observed in all assessment visits across the three types of amblyopia, with a mean improvement of (0.30 ± 0.184) LogMAR. Specifically, anisometropic amblyopia with (0.28 ± 0.18) LogMAR, strabismic amblyopia (0.31 ± 0.18) LogMAR, and mixed amblyopia (0.31 ± 0.18) LogMAR. No significant differences were found between the improvement in visual acuity during the eight control visits and the types of amblyopia (r = 0.174, p = 0.182). However, a significant correlation was observed within all groups in the mean improvement in visual acuity and the severity level (r = 0.712, p = 0.034).

Conclusion

Amblyopia types do not appear to significantly affect the improvement in visual acuity; however, the initial severity of amblyopia may be a key factor influencing the degree of visual recovery achieved with occlusion therapy.

Effectiveness of Dichoptic Therapy for Treating Mild to Moderate Amblyopia in a Tertiary Eye Care Center in South India

PURPOSE

To contribute evidence about the effectiveness of dichoptic therapy in patients with mild to moderate amblyopia.

METHODS

A retrospective study was conducted in patients enrolled for dichoptic therapy on the Bynocs AmblyGo platform (Kanohi Eye Pvt Ltd) from January to August 2023. Data collected included logarithm of the minimum angle of resolution best corrected visual acuity, anterior and posterior segment examination, fixation pattern, dynamic and cycloplegic refraction, orthoptic evaluation, and number of dichoptic therapy sessions. Visual acuity, binocularity, and stereopsis before and after therapy were analyzed.

RESULTS

Of 59 patients (median age: 11 years, range: 5 to 30 years) enrolled, 34 (57.6%) had anisometropic amblyopia, 12 (20.3%) had ametropic amblyopia, 10 (17.0%) had strabismic amblyopia, and 3 (5.1%) had deprivation amblyopia. All 6 (10.2%) and 15 (22.4%) patients who had no binocular single vision for near and distance before therapy, respectively, attained normal binocular single vision on completion, except one who suppressed at distance. Twenty-one (75.0%) had improved near stereopsis, and 21 (60.0%) had improved distance stereopsis. Of 74 eyes treated, 61 (82.4%) had improved visual acuity and 73 (98.6%) improved in at least one tested parameter. A majority of these eyes had residual amblyopia after occlusion therapy.

CONCLUSIONS

Dichoptic therapy improves visual acuity, binocularity, and stereoacuity in patients with amblyopia, including those older than 8 years, especially in partial deprivation, ametropic, and anisometropic amblyopia. [J Pediatr Ophthalmol Strabismus. 2024;61(6):416-424.].

Reconnecting Anisometropic Amblyopic Eyes to the Cortex: VEP-Based Auditory Biofeedback

OBJECTIVE

This study aimed to evaluate the effectiveness of a visual rehabilitation method for anisometropic amblyopia that uses visual evoked potential (VEP) parameters and sound biofeedback to increase objectiveness.

DESIGN

an observational, case-controlled trial.

SETTING

Ophthalmology Clinic, Emergency County Hospital, Cluj-Napoca, Romania.

PARTICIPANTS

Sixteen subjects with amblyopic anisometropia, aged 15-57, and sixteen controls, aged 24-33, were included.

INTERVENTIONS

Subjects were divided into two groups. The control group, composed of normal-vision subjects, and the amblyopic group received 10 training sessions. The rehabilitation program lasted 10 min, took place twice a week, and ran over five consecutive weeks. During each session, the subjects were asked to fixate on a target on the computer screen and were instructed to keep the fixation and maintain the sound of the biofeedback at high frequency.

MAIN MEASURES

The study assessed the main visual parameters at baseline, after 10 sessions, and 1, 3, 6, and 12 months after treatment. Performance was evaluated by measuring visual acuity, contrast sensitivity, and reading velocity (words/minute).

RESULTS

In the experimental group, mean BCVA improved with two rows, which means an improvement in the LogMARLogMAR scale with an average of nine letters. These values tended to be maintained over time. Both groups showed better reading velocities after training, but this parameter has undergone large variability during follow-ups. Contrast sensitivity was also improved and stable.

CONCLUSIONS

Visual rehabilitation with the Retimax Vision Trainer can improve visual performance in patients with amblyopia after the critical period, an improvement that is maintained in most cases for at least one year after treatment.

ChatGPT and Google Assistant as a Source of Patient Education for Patients With Amblyopia: Content Analysis

BACKGROUND

We queried ChatGPT (OpenAI) and Google Assistant about amblyopia and compared their answers with the keywords found on the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) website, specifically the section on amblyopia. Out of the 26 keywords chosen from the website, ChatGPT included 11 (42%) in its responses, while Google included 8 (31%).

OBJECTIVE

Our study investigated the adherence of ChatGPT-3.5 and Google Assistant to the guidelines of the AAPOS for patient education on amblyopia.

METHODS

ChatGPT-3.5 was used. The four questions taken from the AAPOS website, specifically its glossary section for amblyopia, are as follows: (1) What is amblyopia? (2) What causes amblyopia? (3) How is amblyopia treated? (4) What happens if amblyopia is untreated? Approved and selected by ophthalmologists (GW and DL), the keywords from AAPOS were words or phrases that deemed significant for the education of patients with amblyopia. The "Flesch-Kincaid Grade Level" formula, approved by the US Department of Education, was used to evaluate the reading comprehension level for the responses from ChatGPT, Google Assistant, and AAPOS.

RESULTS

In their responses, ChatGPT did not mention the term "ophthalmologist," whereas Google Assistant and AAPOS both mentioned the term once and twice, respectively. ChatGPT did, however, use the term "eye doctors" once. According to the Flesch-Kincaid test, the average reading level of AAPOS was 11.4 (SD 2.1; the lowest level) while that of Google was 13.1 (SD 4.8; the highest required reading level), also showing the greatest variation in grade level in its responses. ChatGPT's answers, on average, scored 12.4 (SD 1.1) grade level. They were all similar in terms of difficulty level in reading. For the keywords, out of the 4 responses, ChatGPT used 42% (11/26) of the keywords, whereas Google Assistant used 31% (8/26).

CONCLUSIONS

ChatGPT trains on texts and phrases and generates new sentences, while Google Assistant automatically copies website links. As ophthalmologists, we should consider including "see an ophthalmologist" on our websites and journals. While ChatGPT is here to stay, we, as physicians, need to monitor its answers.

The relationship between visual acuity loss and GABAergic inhibition in amblyopia

Early childhood experience alters visual development, a process exemplified by amblyopia, a common neurodevelopmental condition resulting in cortically reduced vision in one eye. Visual deficits in amblyopia may be a consequence of abnormal suppressive interactions in the primary visual cortex by inhibitory neurotransmitter γ-aminobutyric acid (GABA). We examined the relationship between visual acuity loss and GABA+ in adult human participants with amblyopia. Single-voxel proton magnetic resonance spectroscopy (MRS) data were collected from the early visual cortex (EVC) and posterior cingulate cortex (control region) of 28 male and female adults with current or past amblyopia while they viewed flashing checkerboards monocularly, binocularly, or while they had their eyes closed. First, we compared GABA+ concentrations between conditions to evaluate suppressive binocular interactions. Then, we correlated the degree of visual acuity loss with GABA+ levels to test whether GABAergic inhibition could explain visual acuity deficits. Visual cortex GABA+ was not modulated by viewing condition, and we found weak evidence for a negative correlation between visual acuity deficits and GABA+. These findings suggest that reduced vision in one eye due to amblyopia is not strongly linked to GABAergic inhibition in the visual cortex. We advanced our understanding of early experience dependent plasticity in the human brain by testing the association between visual acuity deficits and visual cortex GABA in amblyopes of the most common subtypes. Our study shows that the relationship was not as clear as expected and provides avenues for future investigation.

Meridional Amblyopia and Spectacle Correction: A Prospective Interventional Study of Children Aged 4-11 Years

Background Amblyopia, often linked to high astigmatism in children, presents challenges in understanding the contributing factors and visual outcomes. Methods A total of 132 samples were included in this prospective pre- and post-interventional study using the purposive sampling technique. Descriptive statistics were applied for age, gender, uncorrected visual acuity, corrected visual acuity, type, and magnitude of astigmatism. A repeated measure ANOVA was used, and a paired t-test was also done for groups with corrected visual acuity in meridional amblyopia at two follow-ups spaced six months apart. Logistic regression was used to identify the association between astigmatism types and patients' recovery from amblyopia after intervention. Results The age of participants was 4-11 years with meridional amblyopia. Initial findings showed a mean uncorrected visual acuity of 0.73 LogMAR in the right eye (RE) and 0.71 LogMAR in the left eye (LE), improving significantly to 0.35 LogMAR post-intervention in both eyes. The calculated mean difference between the first correction and the first follow-up was 0.12 and 0.13 LogMAR, while it was 0.20 and 0.21 LogMAR in the RE and LE, respectively, at the second follow-up. Spherical refractive errors averaged +0.93 DS, with mean cylindrical refraction indicating predominant with-the-rule corneal astigmatism (-3.46 DS). We observed a significant improvement in visual acuity (p-value < 0.001) and an increase in the magnitude of cylindrical prescription (p-value < 0.001). However, astigmatism types are not associated with response to therapy. Conclusion The study concluded that early detection of meridional amblyopia and early intervention with spectacles significantly improve visual acuity.

Amblyogenic risk factors and validity of vision screening using spot-screener among kindergarten children in Qassim region, Saudi Arabia

PURPOSE

The purpose of the study was to present the outcomes of vision and amblyogenic risk factor (ARF) screening in kindergarten children in the Qassim region, Saudi Arabia.

METHODS

In this cross-sectional study, an optometrist conducted first-level screening in a kindergarten using a spot screener (Welch Allyn) in 2023. Refractive status and ocular alignment were evaluated. The visual acuity of each eye was measured. Those who failed the first screening or had impaired vision were re-evaluated at the second level of screening by an optometrist and pediatric ophthalmologist. Those who failed the screening in Kindergarten were referred to a pediatric ophthalmology clinic for confirmation and management (third level of screening).

RESULTS

We screened 222 children (mean age: 5.9 ± 0.4 years, 111 boys). A total of 59 (26.6%) children failed the spot vision screening test. A vision screening test by an optometrist identified 58 (26.1%) children with impaired vision. Refractive errors (REs) for children who failed the spot screener included hyperopia in 4 (6.7%) children, high myopia (>6.00 D) in 2 (3.4%) children, and astigmatism in 53 (89.83%) children. Compared to the evaluation by optometrists and pediatric ophthalmologists at KGs, spot screening had 0.845 sensitivity and 0.939 specificity. Validity parameters differed for RE, vision impairment, amblyopia, and strabismus. Seventy-one (31.98%) children were referred for third-level screening, but only 32 (44.4%) children attended, and among them, the prevalence of amblyopia was 25%.

CONCLUSION

The high prevalence of amblyopia and undetected ARFs necessitate establishing annual vision screening among 3- to 5-year-old children in the study area.

Unveiling Visual Acuity in 58,712 Four-Year-Olds: Standardized Assessment Defined Normative Visual Acuity Threshold

The purpose was to define the threshold of normal visual acuity (VA), mean monocular and binocular VA, and interocular difference in the uniform cohort of healthy four-year-old children. All the children were recruited from the Croatian National Registry of Early Amblyopia Detection database. LEA Symbols® inline optotypes were used for VA testing at near and distance, binocularly and monocularly. The pass cut-off level was set to ≤0.1 logMAR. The final sample consisted of 58,712 four-year-old children. In total, 83.78% of the children had unremarkable results, and 16.22% of the children were referred to examination. Of those, 92% of the children were referred due to binocular, and 8% of the children due to monocular causes. The children referred due to binocular causes demonstrated a VA of 0.3 ± 0.24, while the children referred due to monocular causes 0.6 ± 0.21. The ROC curve analysis defined the uniform cut-off value for a normative VA of 0.78. We analyzed the largest uniform cohort of 58,712 children, and have determined normative data for binocular and monocular VA tested with gold standard logMAR chart in four-year-old children. The results presented here established no reasoning to further utilize historical protocols in testing VA in preschool children aged ≥ 4 years.

Impact of a Vision Photoscreener in Very Young Children in an Inner-City Pediatric Clinic in Detroit

Pediatric vision screening is important because approximately 80% of visual impairments, including amblyopia, can be prevented or cured, especially if caught early. This retrospective study aims to determine whether the implementation of a machine photoscreener improves vision outcomes in 1- to 4-year-old children in an urban clinic. Before the vision screener, 91 patients were seen (control group), while 205 were seen following its implementation (study group). The number of children screened increased by 27.4% after implementing the photoscreener (57.1% study, 29.7% control, P < .001). All patients who failed the screening, 14.6% in the study period, were referred to ophthalmology (n = 30); 40% (n = 12) were evaluated, and 9 were diagnosed with a true vision abnormality. Instrument vision screening allows children as young as 1 year to be screened and allows for early intervention for potential vision-threatening pathologies in a vulnerable urban population.

Prevalence of visual impairment and estimation of refractive errors among school children in Kakamega, Kenya

AIM

To investigate the prevalence of visual impairment (VI) and provide an estimation of uncorrected refractive errors in school-aged children, conducted by optometry students as a community service.

METHODS

The study was cross-sectional. Totally 3343 participants were included in the study. The initial examination involved assessing the uncorrected distance visual acuity (UDVA) and visual acuity (VA) while using a +2.00 D lens. The inclusion criteria for a subsequent comprehensive cycloplegic eye examination, performed by an optometrist, were as follows: a UDVA<0.6 decimal (0.20 logMAR) and/or a VA with +2.00 D ≥0.8 decimal (0.96 logMAR).

RESULTS

The sample had a mean age of 10.92±2.13y (range 4 to 17y), and 51.3% of the children were female (n=1715). The majority of the children (89.7%) fell within the age range of 8 to 14y. Among the ethnic groups, the highest representation was from the Luhya group (60.6%) followed by Luo (20.4%). Mean logMAR UDVA choosing the best eye for each student was 0.29±0.17 (range 1.70 to 0.22). Out of the total, 246 participants (7.4%) had a full eye examination. The estimated prevalence of myopia (defined as spherical equivalent ≤-0.5 D) was found to be 1.45% of the total sample. While around 0.18% of the total sample had hyperopia value exceeding +1.75 D. Refractive astigmatism (cil<-0.75 D) was found in 0.21% (7/3343) of the children. The VI prevalence was 1.26% of the total sample. Among our cases of VI, 76.2% could be attributed to uncorrected refractive error. Amblyopia was detected in 0.66% (22/3343) of the screened children. There was no statistically significant correlation observed between age or gender and refractive values.

CONCLUSION

The primary cause of VI is determined to be uncorrected refractive errors, with myopia being the most prevalent refractive error observed. These findings underscore the significance of early identification and correction of refractive errors in school-aged children as a means to alleviate the impact of VI.

Changes in ocular biometrics following cycloplegic refraction in strabismic and amblyopic children

This study was aimed to analyze ocular biometric changes following cycloplegia in pediatric patients with strabismus and amblyopia. Cycloplegia is routinely used to measure refractive error accurately by paralyzing accommodation. However, effects on axial length (AL), anterior chamber depth (ACD), keratometry (Km), and white-to-white distance (WTW) are not well studied in this population. This retrospective study examined 797 patients (1566 eyes) undergoing cycloplegic refraction at a Samsung Kangbuk hospital pediatric ophthalmology clinic from 2010 to 2023. Ocular biometry was measured before and after instilling 1% cyclopentolate and 0.5% phenylephrine/0.5% tropicamide. Patients were categorized by strabismus diagnosis, age, refractive error and amblyopia status. Differences in AL, ACD, Km, WTW, and refractive error pre- and post-cycloplegia were analyzed using paired t tests. ACD (3.44 ± 0.33 vs 3.58 ± 0.29 mm, P < .05) and WTW (12.09 ± 0.42 vs 12.30 ± 0.60 mm, P < .05) increased significantly after cycloplegia in all groups except other strabismus subgroup (Cs) in both parameters and youngest subgroup (G1) in ACD. Refractive error demonstrated a hyperopic shift from -0.48 ± 3.00 D to -0.06 ± 3.32 D (P < .05) in overall and a myopic shift from -6.97 ± 4.27 to -8.10 ± 2.26 in high myopia (HM). Also, AL and Km did not change significantly. In conclusion, cycloplegia impacts ocular biometrics in children with strabismus and amblyopia, significantly increasing ACD and WTW. Refractive error shifts hyperopically in esotropia subgroup (ET) and myopically in high myopia subgroup (HM), eldest subgroup (G3) relating more to anterior segment changes than AL/Km. Understanding cycloplegic effects on biometry is important for optimizing refractive correction in these patients.

Protective Effect of Amblyopia on Age-Related Macular Degeneration

PURPOSE

Our aim was to evaluate whether patients with age-related macular degeneration (AMD) and cooccurrent amblyopia are more likely to have diseases diagnosed on both the ipsilateral and the contralateral side in a large Austrian database.

DESIGN

Retrospective cross-sectional study.

METHODS

Setting: Institutional practice.

PATIENT POPULATION

Medical records of all patients who visited the Department of Ophthalmology of the Medical University of Graz between December 1996 and June 2021 were searched for the co-occurrence of AMD and amblyopia.

MAIN OUTCOME MEASURES

Data from patients with AMD diagnosed on 1 eye side were used for further analysis. Spectral-domain optical coherence tomography images were analyzed to confirm the lateral asymmetry of AMD.

RESULTS

A total of 327,443 patients were screened for the co-occurrence of AMD and amblyopia. Of them, 8742 patients had AMD diagnosed on 1 eye side and 5051 patients had unilateral amblyopia. In total, 163 patients were found to have AMD diagnosed on 1 side and unilateral amblyopia in combination. Of these, 126 patients had AMD and amblyopia on contralateral sides and 37 had AMD and amblyopia on the ipsilateral side (P < .001).

CONCLUSIONS

Less amblyopic patients had AMD diagnosed on the amblyopic eye compared with the nonamblyopic eye. In cases of lateral asymmetry, the nonamblyopic eye is more likely to have the more advanced form of AMD.

Expression of early growth responsive gene-1 in the lateral geniculate body of kittens with amblyopia caused by monocular form deprivation

OBJECTIVE

The expression of early growth responsive gene-1 (Egr-1) in the lateral geniculate body in the normal kittens and those affected with amblyopia caused by monocular visual deprivation was compared to explore the potential significance of Egr-1 in the pathogenesis of amblyopia.

METHODS

A total of 30 healthy kittens were equally and randomly divided into the control (n = 15) and the deprivation group (n = 15). The kittens were raised in natural light and the right eyes of the deprived kittens were covered with a black opaque covering. Pattern visual evoked potential (PVEP) was measured before and 1, 3, and 5 weeks after covering. Five kittens from each group were randomly selected and euthanized with 2% sodium pentobarbital (100 mg/kg) during the 1st, 3rd and 5th week after covering. The expression of Egr-1 in the lateral geniculate body in the two groups was compared by performing immunohistochemistry and in situ hybridization.

RESULTS

After three weeks of covering, PVEP detection indicated that the P100 wave latency in the deprivation group was significantly higher than that in the control group (P < 0.05), whereas the amplitude decreased markedly (P < 0.05). The number of the positive cells (P < 0.05) and mean optical density (P < 0.05) of Egr-1 protein expression in the lateral geniculate body of the deprivation group were found to be substantially lower in comparison to the normal group, as well as the number (P < 0.05) and mean optical density of Egr-1 mRNA-positive cells (P < 0.05). However, with increase of age, positive expression of Egr-1 in the control group showed an upward trend (P < 0.05), but this trend was not noted in the deprivation group (P > 0.05).

CONCLUSIONS

Monocular form deprivation can lead to substantially decreased expressions of Egr-1 protein and mRNA in the lateral geniculate body, which in turn can affect the normal expression of neuronal functions in the lateral geniculate body, thereby promoting the occurrence and development of amblyopia.

Cost-effectiveness of screening for amblyopia among kindergarten children in China

OBJECTIVE

Current cost-effectiveness analyses of amblyopia screening are mainly from western countries. It remains unclear whether it is cost-effective to implement a preschool amblyopia screening programme in China. Our study aimed to evaluate the cost-effectiveness of a hypothetical kindergarten-based amblyopia screening versus non-screening among 3-year-old children.

METHODS

We developed a decision tree combined with a Markov model to compare the cost and effectiveness of screening versus non-screening for 3-year-old children from a third-party payment perspective. The primary outcomes were quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio (ICER). Costs were obtained from expert opinions in different regions of China. Transition probabilities and health utilities were mainly based on published literature and open sources. Sensitivity analyses were performed to assess the impact of parameters' uncertainty on results.

RESULTS

Base-case analysis demonstrated that the ICER of screening versus non-screening was $17,466/QALY, well below the WTP threshold ($38,223/QALY) for China. One-way sensitivity analysis showed that the prevalence of amblyopia, the transition probability per year from untreated amblyopia to healthy, and the discount rate were the top three factors. The likelihood of cost-effectiveness of screening compared with non-screening was 92.56%, according to probabilistic sensitivity analysis. Scenario analysis also indicated that ICER was lower than the WTP threshold even if the time horizon was shortened or the screening was delayed to the age of 4 or 5.

CONCLUSIONS

Amblyopia screening could be considered a cost-effective strategy compared to non-screening for 3-year-old children in China. Screening for children at the age of 4 or 5 may even yield better results.

The Ayounkon project: visual impairment, eye diseases and unmet eye care needs in the Syrian refugee population and the hosting community in Lebanon

AIM

To report on the distribution of eye diseases, aetiologies of severe visual impairment/blindness (SVI/BL) and unmet eye care needs of the Syrian refugee population and the Lebanese host community.

METHODS

This retrospective study analysed the data of patients that were examined during the Ayounkon project -an eye health care project offering medical and surgical treatment for Syrian refugees and Lebanese host community in the Bekaa Valley in Lebanon. The project took place in three different primary health care centres and involved cooperation between several NGOs and ophthalmologists working on a voluntary basis. Data was analysed for distribution of eye diseases and aetiologies responsible for monocular and binocular SVI/BL.

RESULTS

A total of 2067 patients were included, 677 were children < 18 years. The most frequent pathologies were ocular allergy (10%), and cataract (7.4%). 158 patients (7.6%) were referred for surgery. Glasses were prescribed for 1103 patients (53.4%), of whom 242 (21.9%) were children of school age. SVI/BL was found in 276 patients (13%). The condition was bilateral in 116 patients (42%). SVI/BL was significantly more frequent in the Syrian population than in the Lebanese (186 patients, 14.8% versus 86 patients, 11.3%; p = 0.04). The main causes for SVI/BL were cataract, keratoconus/corneal decompensation and amblyopia.

CONCLUSION

The Syrian refugee population and the Lebanese host community have a high prevalence of ophthalmic pathologies and SVI/BL. Visual impairment is more prevalent in the refugee population. Our findings underscore the importance of targeted interventions and access to eye care services for these populations.

The impact of eye dominance on fixation stability in school-aged children

The aim of the study was to analyze the stability of dominant and non-dominant eye fixations, as well as the influence of development on fixation stability. The study analyzed fixation stability in 280 school-age children, ranging in age from 7 to 12 years old. Fixation stability was determined by calculating the bivariate contour ellipse area (BCEA). During the fixation task, eye movements were recorded using the Tobii Pro Fusion eye tracking device at a 250 Hz sampling frequency. The results indicate that the fixation stability of dominant and non-dominant eyes, as well as the fixation stability of each eye regardless of dominance, improves as children grow older. It was found that for 7 and 8- year-old children, fixation in the dominant eye is significantly more stable than in the non-dominant eye, while in older children, there is no significant difference in fixation stability between the dominant and non-dominant eye.

Variations in the prevalence of vision impairment across regions among school children in Telangana State, South India

Purpose

Undetected vision impairment (VI) could negatively affect the overall development in children. School vision screening program is a viable and cost-effective approach for the early identification and management of VI.

Aim

This study aims to estimate the prevalence of VI, its risk factors, and ocular morbidity among school children in Telangana, South India.

Methods

Children aged 4-15 years attending schools in the study area were screened in this study. The vision screenings were performed in schools by trained community eye health workers using 6/12 tumbling E optotypes. Children who failed the test and/or presented with other eye conditions were referred to vision centers or secondary and tertiary eye care centers. A comprehensive eye examination was conducted in these centers, including cycloplegic refraction and fundus examination.

Results

A total of 774,184 children, with a mean age of 9.4 ± 3.27 years, were screened. Overall, 51.49% (N = 398,596) were male. In total, 4.33% [N = 33,528; 95% confidence interval (CI): 4.29-4.38] required referral services, while 1.16% (N = 9,002) had a presenting visual acuity of < 6/12. Multivariate analysis showed a high risk of VI among older children [Adj. odds ratio (OR): 5.75; 95% CI: 5.18-6.38], those with disabilities (Adj. OR: 5.12; 95% CI: 4.14-6.33), female gender (Adj. OR: 1.29; 95% CI: 1.24 - 1.35), and those residing in the urban areas (Adj. OR: 2.87; 95% CI: 2.42-3.39). The main cause of VI was uncorrected refractive errors (74.14%).

Conclusion

The prevalence of VI among school children was 1.16% in Telangana, South India, and refractive error was the leading cause of VI among this population. Increasing age, urban location, female gender and other disabilities increase the risk of VI among children.

Qualitative Exploration of the Visual Function Impairments and Health-Related Quality of Life Impacts of Amblyopia in Adult and Pediatric Populations

INTRODUCTION

Amblyopia is a reduction in vision in one or both eyes due to impaired development of the visual pathway. This study explored the experience of amblyopia and treatment from the patient, caregiver, and clinician perspectives.

METHODS

A targeted literature review, including a review of social media listening (SML) studies, was conducted. Next, qualitative interviews were conducted with amblyopia patients, caregivers of children with amblyopia, and ophthalmologists with experience treating patients with amblyopia. The findings informed the development of a disease model. Amblyopia clinical experts provided input at key stages.

RESULTS

Twelve data sources were reviewed, including qualitative studies in the literature and SML studies. Overall, 133 patients/caregivers were interviewed (23 adults, 16 adolescents, 47 child-caregiver dyads), plus 10 ophthalmologists from the United States, France, and Germany. Reduced visual acuity, impaired depth perception, impaired peripheral vision, and double vision were the most frequently reported symptoms. Amblyopia impacted daily activities (reading, using digital devices), the ability to move around, school/work (productivity, seeing the board in class), emotional well-being (frustration, sadness), and social functioning (difficulty socializing). Treatments, including patching and corrective lens, also impacted daily activities (using digital devices, sports/leisure), mobility (bumping into things), and work/school (tasks taking longer) as well as emotional well-being (embarrassment), and social functioning (bullying/stigma).

CONCLUSION

The findings contribute valuable insights into the adult and pediatric experience of amblyopia from a multi-stakeholder perspective. The findings were used to critically assess existing clinical outcome assessments and supported the development of patient- and observer-reported outcome measures for use in amblyopia clinical trials.

OCT-Angiography Findings in Children with Anisometropic Amblyopia

PURPOSE

The purpose of this prospective study is to show findings of OCT angiography in children with anisometropic amblyopia with a statistically significant difference, regardless of the type of refractive disorder, between the amblyopic and the fellow eye. This research aimed to establish whether there is a difference in vascular density [VD] and size of the foveal avascular zone [FAZ] in the superficial capillary plexus [SCP].

METHODS

All children between 9 and 18 years of age who were treated at the Outpatient Clinic for Orthoptics and Pleoptics of the Department of Ophthalmology, University Medical Centre Maribor from January 2020 to December 2022 due to unilateral anisometric amblyopia were enrolled in our study. Fourteen children met the criteria. Cirrus 5000 high-resolution OCT with AngioPlex OCT angiography was used to analyze the size of the FAZ and VD in the SCP and TCS. The paired t-test or Wilcox signed-rank test [p < 0.05] was used for statistical analysis of each parameter between the amblyopic and fellow eye.

RESULTS

Mean child age was 13 years ± 2.9 and ranged from 9 to 18 years. Most of the children [85.7%] were boys. The VD of the SCP did not show statistically significant differences between the visually impaired and control eyes [p = 0.328]. The comparison of the FAZ area between the two eyes was also not statistically significant [p < 0.808]. There was also no statistically significant difference in central macular thickness [TCS] [p < 0.291].

CONCLUSIONS

Our research results show no statistically significant differences in the VD and the FAZ of the SCP, and in the TCS between the amblyopic and fellow eye in children with unilateral anisometropic amblyopia. Our research did not confirm the results of certain previous studies in which a lower density of the capillary network was present in the visually impaired eye. Further studies with more children are necessary to confirm our results.

Comparison of Retinal and Choroidal Microvasculature Changes in Monocular Amblyopic and Non-amblyopic Eyes following Short-term Patch Occlusion Treatment

PURPOSE

Our objective was to investigate whether there were differences in the short-term changes of retinal and choroidal microvasculature between amblyopic and non-amblyopic eyes after patch occlusion treatment in patients with monocular amblyopia. Additionally, we aimed to determine if these changes were associated with improvements in clinical parameters.

METHODS

We conducted a retrospective, longitudinal paired-eye case-control study by analyzing the medical records of patients under the age of 12 who had monocular amblyopia and underwent patch occlusion treatment for a duration of 2 to 12 months. Using optical coherence tomography angiography images, we compared the foveal avascular zone width, retinal blood vessel density (VD), choroidal thickness (CT), and choroidal vascularity index (CVI) in amblyopic and non-amblyopic eyes before and after patch occlusion treatment. We analyzed the correlations between the aforementioned parameters and changes in best-corrected visual acuity (BCVA) and stereopsis.

RESULTS

Overall, 114 eyes from 57 patients were enrolled. At baseline, parafoveal superficial plexus VD, foveal and parafoveal deep capillary plexus VD (DCPD) were lower by 0.994 ± 3.312% (p = .026), 2.403 ± 8.273% (p = .033), and 2.469 ± 4.095% (p < .001), respectively; CT was thicker by 30.6 ± 90.7 μm (p = .014); and CVI was higher by 1.920 ± 3.432% (p < 001) in the amblyopic eyes than in the non-amblyopic eyes. Following short-term patch occlusion treatment, foveal and parafoveal DCPD increased by 1.264 ± 3.829% (p = .017) and 1.028 ± 3.662% (p = .036), respectively, CT thinned by 15.5 ± 51.5 μm (p = .019), and CVI decreased by 1.296 ± 3.997% (p = .018) in the amblyopic eyes. Following patch occlusion treatment, as the foveal DCPD decreased and CVI increased, the BCVA improved (p = .017 and .035, respectively).

CONCLUSION

Following patch occlusion treatment, increased foveal DCPD and decreased CVI were associated with improved BCVA.

Effects of virtual reality on the treatment of amblyopia in children: A systematic review and meta-analysis

PROBLEM

Virtual reality technology has been used to treat amblyopia in children. However, it is unclear how virtual reality technology differs from conventional patching therapy in terms of effectiveness.

ELIGIBILITY CRITERIA

Eligible randomized controlled studies were retrieved from PubMed, Embase, Scopus, the Cochrane Library, and Web of Science through February 2023.

SAMPLE

Eight studies included 10 trials with 459 participants were included in the current meta-analysis. Two studies (Herbison et al., 2016; Huang et al., 2022) included two trials each. Thus, a total of ten trials were included in the current meta-analysis.

RESULTS

Overall, virtual reality technology treatment significantly improved visual acuity by 0.07 log MAR (95% confidence interval [CI], -0.11 to -0.02; P < 0.001; I2 = 94.4%) compared with traditional patching therapy. In addition, subgroup analyses also revealed that treatment with virtual reality technology was more effective when the child was younger than seven years old, or when the duration of the intervention was no more than twenty hours.

CONCLUSIONS

Virtual reality technology treatment showed significant effects in improving visual acuity in children who were seven years of age or younger with amblyopia.

IMPLICATIONS

Virtual reality technology treatment is effective in treating amblyopia in children. Virtual reality therapy is also entertaining and popular among children and can be applied to the treatment of amblyopia in children in the future.

The blinq™ Vision Screener in Detection of Amblyopia and Strabismus

PURPOSE

The blinq (Rebion Inc) is a new screening device designed to directly detect amblyopia and strabismus rather than amblyopia risk factors. We performed an independent assessment of the effectiveness of the blinq in detecting amblyopia and strabismus.

DESIGN

Prospective clinical validity analysis of a screening device based on sensitivity and specificity.

METHODS

Children presenting for examination in the pediatric ophthalmology clinic underwent screening with the blinq before examination by a pediatric ophthalmologist blinded to the screening results. Results of the blinq and examination findings of strabismus or amblyopia were compared.

RESULTS

In our cohort of 267 children with an average age of 6.3 years, the sensitivity of the blinq to detect amblyopia or any constant strabismus was 87.5% (78.2%-93.8%) and specificity was 51.3% (43.9%-58.7%). Using the previously described "appropriate referral gold standard" criteria, including children with intermittent strabismus and high refractive error, the sensitivity increased to 91.3% and the specificity to 63.2%. We found a high number of children (44 [16%]) upon whom the blinq timed out and were included as automatic referrals.

CONCLUSIONS

Our results support use of the blinq as a screening device to detect amblyopia and strabismus in children.

The Amblyopia Quality of Life (AmbQoL): Development and Content Validation of a Novel Health-Related Quality of Life Instrument for Use in Adult and Pediatric Amblyopia Populations

INTRODUCTION

Amblyopia is a neurodevelopmental vision disorder, characterized by poor vision in one or both eyes. Given the lack of existing clinical outcome assessments (COA) considered fit-for-purpose for amblyopia clinical trials, this study developed new COAs to assess amblyopia symptoms and health-related quality of life (HRQoL) impacts in adult and pediatric amblyopia populations that conform with best practice standards and regulatory guidelines.

METHODS

Findings from a targeted qualitative literature review informed the development of three versions of the new Amblyopia Quality of Life Questionnaire (AmbQoL): a patient-reported outcome measure (PRO) for individuals aged 13 years and older, a PRO for children aged 9-12 years, and an observer-reported outcome measure (ObsRO) for caregivers of children aged 4-8 years. Qualitative interviews were conducted with the target populations, and with ophthalmologists experienced in treating amblyopia patients to evaluate the content validity for further development of the AmbQoL. A translatability assessment was conducted to ensure cultural appropriateness and usability across multiple languages. Feedback from Food and Drug Administration (FDA) was also sought on the instruments, and clinical experts provided input at key stages.

RESULTS

Interviews were conducted with 112 patients/caregivers and ten ophthalmologists from the USA, France, and Germany. The instructions, items, and response options were well understood across all AmbQoL versions. Feedback from the patients, caregivers, ophthalmologists, the translatability assessment, the FDA, and the expert clinicians informed minor wording modifications to enhance clarity and translatability. Some items were removed due to low relevance. The study resulted in a 23-item adult/adolescent PRO, 24-item child PRO, and 12-item ObsRO, each employing a 7-day recall period.

CONCLUSION

Each AmbQoL version has documented support for its face and content validity for use in amblyopia populations aged ≥ 4 years. Further research is necessary to evaluate the psychometric measurement properties of the AmbQoL instruments to enable their use in amblyopia treatment trials.

Amblyopia: A review of unmet needs, current treatment options, and emerging therapies

Amblyopia is a global public health issue with extensive, multifaceted impacts on vision and quality of life (QoL) for both patients and families. Geographical variation exists in the management of amblyopia, with traditional mainstay treatments, optical correction, and fellow eye occlusion most successful when implemented at an early age. In recent years, however, studies demonstrating meaningful improvements in older children and adults have challenged the concept of a complete loss of visual processing plasticity beyond the critical period of visual development, with growing evidence supporting the potential efficacy of emerging, more engaging, binocular therapies in both adults and children. Binocular approaches aim to restore deficits in amblyopia that extend beyond monocular visual acuity impairment, including binocular fusion and visuomotor skills. In view of this, incorporating outcome measures that evaluate the visual performance and functional ability of individuals with amblyopia will provide a clearer understanding of the effect of amblyopia on QoL and a more comprehensive evaluation of amblyopia therapies.

Frequency of Amblyopia in strabismus patients presenting to tertiary care hospital

Objective: The rationale of study was to find the magnitude of amblyopia with reference to type of squint among the strabismus patients visiting Hayatabad Medical Complex Peshawar, Pakistan. Materials and Methods: After ethical approval, a cross sectional study was carried out in the Department of Ophthalmology, Hayatabad Medical Complex, Peshawar, Pakistan, from April 2022 to October 2022, the total number of patients included being 237. Results: Amblyopia was observed in 113 out of 160 (70.6%) cases of uniocular squint, while in alternating squint it was found to be 11 out of 77 (14.2%). Amblyopia in patients with esotropia was seen in 73.2% (107 out of 146), while 59.3% (54 out of 91) exotropia had associated amblyopia. Conclusion: Strabismus amblyopia leads to developmental arrest of vision in early critical years of life. Permanent visual loss can be avoided with comprehensive screening and detailed examination of strabismic patient.

Long-Term Efficacy of the Combination of Active Vision Therapy and Occlusion in Children with Strabismic and Anisometropic Amblyopia

This retrospective study was conducted to evaluate the efficacy of the combined treatment of occlusion and active vision therapy in a total of 27 amblyopic children, including 14 strabismic and 13 anisometropic cases. For such purpose, changes in distance and near visual acuity as well as in the binocular function was evaluated during a two-year follow-up. In both amblyopia groups, significant improvements were found in distance and near visual acuity in the non-dominant eye (p < 0.001). In the strabismic amblyopia group, the percentage of patients with binocular function score (BF) > 3.3 decreased significantly from a baseline value of 64.3% to a two-year follow-up value of 7.1% (p < 0.001). In the anisometropic amblyopia group, this percentage also decreased significantly from a baseline value of 15.4% to a two-year follow-up value of 0.0% (p < 0.001). No recurrences were observed in the anisometropic amblyopia group, whereas recurrence occurred in two cases of the strabismic amblyopia group after finishing the vision rehabilitation process. In conclusion, the combined approach of the treatment evaluated is efficacious for providing an improvement in visual acuity and binocular function in both anisometropic and strabismic amblyopia, which was maintained over time.