Blindness Research Articles

Navigation Training for Persons With Visual Disability Through Multisensory Assistive Technology: Mixed Methods Experimental Study

Background Visual disability is a growing problem for many middle-aged and older adults. Conventional mobility aids, such as white canes and guide dogs, have notable limitations that have led to increasing interest in electronic travel aids (ETAs). Despite remarkable progress, current ETAs lack empirical evidence and realistic testing environments and often focus on the substitution or augmentation of a single sense. Objective This study aims to (1) establish a novel virtual reality (VR) environment to test the efficacy of ETAs in complex urban environments for a simulated visual impairment (VI) and (2) evaluate the impact of haptic and audio feedback, individually and combined, on navigation performance, movement behavior, and perception. Through this study, we aim to address gaps to advance the pragmatic development of assistive technologies (ATs) for persons with VI. Methods The VR platform was designed to resemble a subway station environment with the most common challenges faced by persons with VI during navigation. This environment was used to test our multisensory, AT-integrated VR platform among 72 healthy participants performing an obstacle avoidance task while experiencing symptoms of VI. Each participant performed the task 4 times: once with haptic feedback, once with audio feedback, once with both feedback types, and once without any feedback. Data analysis encompassed metrics such as completion time, head and body orientation, and trajectory length and smoothness. To evaluate the effectiveness and interaction of the 2 feedback modalities, we conducted a 2-way repeated measures ANOVA on continuous metrics and a Scheirer-Ray-Hare test on discrete ones. We also conducted a descriptive statistical analysis of participants’ answers to a questionnaire, assessing their experience and preference for feedback modalities. Results Results from our study showed that haptic feedback significantly reduced collisions (P=.05) and the variability of the pitch angle of the head (P=.02). Audio feedback improved trajectory smoothness (P=.006) and mitigated the increase in the trajectory length from haptic feedback alone (P=.04). Participants reported a high level of engagement during the experiment (52/72, 72%) and found it interesting (42/72, 58%). However, when it came to feedback preferences, less than half of the participants (29/72, 40%) favored combined feedback modalities. This indicates that a majority preferred dedicated single modalities over combined ones. Conclusions AT is crucial for individuals with VI; however, it often lacks user-centered design principles. Research should prioritize consumer-oriented methodologies, testing devices in a staged manner with progression toward more realistic, ecologically valid settings to ensure safety. Our multisensory, AT-integrated VR system takes a holistic approach, offering a first step toward enhancing users’ spatial awareness, promoting safer mobility, and holds potential for applications in medical treatment, training, and rehabilitation. Technological advancements can further refine such devices, significantly improving independence and quality of life for those with VI.

Transformer-Enhanced Retinal Vessel Segmentation for Diabetic Retinopathy Detection Using Attention Mechanisms and Multi-Scale Fusion

Eye health has become a significant concern in recent years, given the rising prevalence of visual impairment resulting from various eye disorders and related factors. Global surveys suggest that approximately 2.2 billion individuals are visually impaired, with at least 1 billion affected by treatable diseases or ailments. Early detection, treatment, and screening for fundus diseases are crucial in addressing these challenges. In this study, we propose a novel segmentation model for retinal vascular delineation aimed at diagnosing diabetic retinopathy. The model integrates CBAM (Channel-Attention and Spatial-Attention) for enhanced feature representation, JPU (Joint Pyramid Upsampling) for multi-scale feature fusion, and transformer blocks for contextual understanding. Leveraging deep-learning techniques, our proposed model outperforms existing approaches in retinal vascular segmentation, like achieving a Mean IOU of 0.8047, Recall of 0.7254, Precision of 0.8492, F1 Score of 0.7824, and Specificity of 0.9892 for CHASEDB1 dataset. Extensive evaluations on benchmark datasets demonstrate its efficacy, highlighting its potential for automated diabetic retinopathy screening.

Retardation of myopia by atropine regimes

Myopia is a huge health problem due to its high frequency, vision losses and public health cost. According to the World Health Organization, at least 2.2 billion people have vision impairment. Although myopia can be controlled at its early and middle stages, unfortunately, no cure can be achieved so far. Among the methods to control myopia, atropine, a muscarinic receptor antagonist, is the oldest but still the most effective for retardation of myopia progression. Despite such a fact, standard protocols have not been established for clinicians to use atropine for treatment of myopia. In this article, a concise and up to date summary of myopia epidemiology and pathogenesis and summarized therapeutic effects and side effects, possible mechanisms and application methods of atropine were provided in hope for clinical doctors to effectively control this problematic disease. At present, the protocol is recommend: use higher dose (1%) of atropine intermittently to effectively slowdown myopia progression in schoolchildren for 2y, and to significantly reduce side effects of atropine by decrease of atropine frequency for 1y and inhibit myopic rebound by withdrawal of topical atropine gradually for 1y. Application of a lower dose (0.05%) atropine regime should also be considered due to its effectiveness and application at regular basis.

Influence of surgical timing on the visual prognosis of patients suffering from a pituitary apoplexy with visual impairment.

Pituitary apoplexy is a clinical syndrome that can cause vision loss and oculomotor (OM) deficits. Neurosurgical decompression is still considered the treatment of choice for those with visual impairment. We aim to explore the influence of timing of neurosurgical decompression on visual outcome. Multicentre retrospective study of patients presenting with pituitary adenoma and pituitary apoplexy who were operated in three Spanish tertiary hospitals between 2008 and 2022. We identified 49 patients with pituitary apoplexy with visual symptoms and were operated. Among the visual symptoms, 35 patients (73%) had visual acuity (VA) impairment and 33 (67%) had an OM nerve paresis. Twenty-three of the 35 patients improved their VA, and 24 of the 33 improved their OM nerve paresis after surgery. The median time between apoplexy to surgery was 10 days (range 0-164). Regarding visual acuity, 50% (3 out of 6) of those operated within 3 days of apoplexy showed improvement, compared to 69% (20 out of 29) of those operated beyond (p = 0.37).Regarding OM paresis, 62.5% (5 out of 8) of those operated within 3 days of apoplexy improved, compared to 76% (19 out of 25) of those operated beyond (p = 0.56).Mean apoplexy to surgery time was 18 ± 19 days in those whose VA improved (vs. 32 ± 51; p = 0.46); and mean apoplexy to surgery time for those whose OM symptoms improved was 21+/- 35 days (vs. 24 +/- 37; p = 0.86). Our results suggest that timing of neurosurgical decompression does not affect the visual outcome of patients with pituitary apoplexy.

Prevalence of diabetic retinopathy and its associated risk factors among adults in Ethiopia: a systematic review and meta-analysis.

Diabetic retinopathy is a complication of diabetes mellitus and a leading cause of blindness and visual impairment globally. Limited information existed on the epidemiology of diabetic retinopathy at the national level in Ethiopia. Thus, the objective of this review was to determine the pooled prevalence of diabetic retinopathy and its associated risk factors in Ethiopia. A systematic review and meta-analysis was conducted using previous primary studies that were found in electronic databases such as Web of Science, Scopus, PubMed, CINHAL, Google Scholar, and online African journals. We evaluated the quality of the included studies using the Newcastle-Ottawa Assessment Scale. The random-effects model was applied because heterogeneity was expected. I-Square and the Cochrane Q statistics were used to evaluate heterogeneity. Publication bias was examined using Egger's test and a funnel plot. A random-effect meta-analysis was applied to pool the odds ratios of risk factors to determine the association between the independent and dependent variables. After 598 articles were found, 22 studies that met the eligibility requirements were included. The pooled prevalence of retinopathy among patients with diabetes in Ethiopia was 24.35% (95% CI: 18.88-29.83), with considerable heterogeneity (I2 = 98.18%, p < 0.001). Ten years and longer with diabetes (AOR = 4.36, 95% CI: 1.71-7.01), hypertension (AOR = 2.54, 95% CI: 1.45-3.63), poor glycemic control (AOR = 3.83, 95% CI: 1.62-6.04), and positive proteinuria (AHR = 1.55, 95% CI: 1.02-2.07) were risk factors for diabetic retinopathy. Retinopathy affects one in four patients with diabetes. Diabetic patients with longer duration, hypertension, poor glycemic control, and positive proteinuria should receive special care.

Material Constraints for Assistant-Supported Learning

This paper explores classroom desk interaction where the student has a visual impairment (VIS), and the interaction involves a third supportive party, the student’s learning support assistant. Based on video recordings and multimodal conversation analysis, the paper examines how a VIS, his assistant, and the teacher within a contingent socio-material environment work toward solving an assignment. The analysis is organized following the sequential unfolding of the assignment-solving situation, going from a) determining the need for teacher assistance, b) the recruitment of the teacher’s assistance with the assignment, c) how the participation framework for the joint activity of reviewing the assignment is established with the assistant positioning herself as a fellow “learner”, and d) how the issue is identified and solved. The analysis shows the situated properties of the socio-material environment in which the participants and the local material contingencies are assembled and thus become consequential for the collaborative and observable production of the situation.

Out-of-Field Teachers: Issues and Strategies for Teaching Students with Visual Impairment

Out-of-Field Teachers: Issues and Strategies for Teaching Students with Visual Impairment

Effect of self-determination training on personality characteristics in adolescents with visual impairment

Effect of self-determination training on personality characteristics in adolescents with visual impairment

A cross-sectional study of fundus lesion characteristics in patients with acute visual impairment caused by COVID-19 infection.

To investigate the characteristics of acute visual dysfunction and fundus lesions in patients with COVID-19 pneumonia. A retrospective case series study was conducted. Data from 48 patients (96 eyes) with COVID-19 infection who presented to our ophthalmology department with acute onset visual disturbance between December 5, 2022, and February 28, 2023 were collected. Asymptomatic patients and those who had already recovered were excluded. Data collected included patient demographics, ophthalmic examinations, multicolor imaging (MCI), infrared autofluorescence (IR), spectral-domain optical coherence tomography (OCT), fundus fluorescein angiography (FFA). Of the 48 patients, 15 were male and 33 were female, with a mean age of 32 years. All patients had bilateral involvement. OCT showed hyperreflective signals in the outer plexiform layer and outer nuclear layer of the macular region in all 96 eyes of 48 patients (100%). Additionally, 66 eyes of 33 patients (68.8%) of eyes demonstrated abnormal reflectivity in the ellipsoid and interdigitation zones. MCI revealed petaloid or wedge-shaped hyperreflective areas in the macula in 46 (47.9%) of eyes, corresponding to hyporeflective areas on IR. Cotton-wool spots were observed in the peripapillary or posterior pole area in 54 (56.3%) of eyes. COVID-19 infection can lead to acute, bilateral, symmetric, and widespread retinal damage. Characteristic findings can be observed in ophthalmological examinations such as OCT, MCI, and IR.

A deep dive into penetrating ocular trauma: Insights from a South Indian tertiary eye care center

Penetrating ocular trauma is a significant cause of visual impairment and blindness worldwide. In India, with its vast and diverse population, understanding the epidemiology and patterns of Penetrating ocular trauma is crucial for effective prevention and management. This study aims to investigate the prevalence, characteristics, and outcomes of penetrating ocular trauma in the South Indian population. By analyzing data from a tertiary eye care center in South India, this research seeks to contribute to the existing knowledge base and inform evidence-based interventions to reduce the burden of penetrating ocular trauma in this region.To analyze the clinical profile, management, and outcomes of penetrating ocular trauma cases at a tertiary eye care center in South India.A retrospective review of medical records from January 2024 to June 2024 was conducted. Data collected included demographic details, mode of injury, clinical presentations, management approaches, and visual outcomes.Out of 150 cases, 120 were male (80%) and 30 female (20%). The majority of cases occurred in the 20-40 age group (60%). Common causes included workplace accidents (45%), domestic injuries (30%), and road traffic accidents (15%). Initial visual acuity varied from no light perception to &amp;#62;6/18. Surgical intervention was required in 90% of cases. Post-operative follow-up indicated that 60% achieved a visual acuity of 6/60 or better, while 20% had no light perception.Penetrating ocular trauma predominantly affects young males in South India, with workplace injuries being a major cause. Early surgical intervention improves visual outcomes. Public awareness and safety measures could reduce the incidence of such injuries.

Outcomes and complications of cataract surgery using phacoemulsification in eyes with and without pseudo exfoliation syndrome

Cataract remains a significant cause of visual impairment globally, with pseudo exfoliation syndrome (PEX) posing additional challenges for cataract surgery. This study aimed to compare outcomes and complications in patients with and without PEX undergoing phacoemulsification for senile cataract. A total of 70 patients were divided into two groups: PEX (Group 1) and non-PEX (Group 2). Surgical procedures were performed, and outcomes were evaluated. Group 1 exhibited smaller pupil diameter and higher rates of advanced cataracts and intraoperative complications. Despite similar postoperative parameters, Group 1 showed increased inflammatory response and poorer initial visual recovery. Tailored management strategies for PEX patients undergoing cataract surgery are warranted.

Evaluation of mesenchymal stem cells as an in vitro model for inherited retinal diseases

Retinal pathologies are major causes of vision impairment and blindness in humans, and inherited retinal diseases (IRDs), such as retinitis pigmentosa, Leber congenital amaurosis, and Stargardt disease, greatly contribute to this problem. In vitro disease modeling can be used for understanding the development of pathology and for screening therapeutic pharmaceutical compounds. In the preclinical research phase, in vitro models complement in vivo models by reducing animal studies, decreasing costs, and shortening research timelines. Additionally, animal models may not always accurately replicate the human disease phenotype. This review examines the types of cells that can be used to create in vitro IRD models, including retina-specific cell lines, primary retinal cells, induced pluripotent stem cells (iPSCs), and more. Special attention is given to mesenchymal stem cells (MSCs), which are characterized by various isolation sources, relative ease of isolation, and straightforward differentiation. MSCs derived from bone marrow (BM), adipose tissue (AT), dental tissue (DT), umbilical cord (UC), and other sources can differentiate into retinal cells, including photoreceptor cells and retinal pigment epithelial (RPE) cells, dysfunction of which is most commonly associated with IRDs. Subsequent differentiation of MSCs into retinal cells can be carried out via various methods: culturing in induction media supplemented with certain growth factors, co-culturing with retinal cells or in their conditioned media, or regulating gene expression with viral vector-delivered transcription factors (TFs) or microRNAs (miRNAs). Compared to the popular iPSCs, for example, MSC-based models are significantly cheaper and faster to obtain, making them more feasible for large-scale drug screening. Nevertheless, the existing differentiation methods need further optimization for this promising platform to receive the success it deserves.

Correcting near vision impairment and women’s empowerment: a before-after mixed-methods study among older Zanzibari craftswomen

ObjectiveTo understand if presbyopia correction could empower older craftswomen entrepreneurs living in Zanzibar.DesignMixed-method, before-after intervention study.SettingUnguja and Pemba islands, Zanzibar.Participants209 craftswomen (weaving, tailoring and sewing, pottery and producing oil and...

Ocular outcomes of toxoplasmosis in the Amazon-Cerrado transition zone, Brazil: a population-based study.

Eye damage represents one of the gravest outcomes of toxoplasmosis, potentially leading to varying degrees of vision impairment, up to and including blindness. Monitoring ophthalmological indicators in individuals affected by toxoplasmosis, alongside understanding its impact on visual acuity, can motivate the scientific community to advocate for strategies to prevent vision loss associated with toxoplasmosis. This is a retrospective study analysing medical records and clinical documentation from patients at an ophthalmological clinic in a city located at the intersection of the Cerrado and Amazon Forest biomes. It was noted that >20% of patients exhibited visual acuity ≤20/200, a condition medically recognized as blindness for the affected eye. Our study highlights a significant portion of individuals experiencing lasting visual impairments due to toxoplasmosis. These findings remain obscured by the existing national guidelines, which only mandate reporting for congenital and gestational toxoplasmosis cases, thereby overlooking sporadic manifestations and their consequential effects. The effort to identify ophthalmologic consequences is crucial both for personalized clinical care and for shaping national guidelines for managing toxoplasmosis.

Case Report: Periocular Steroid Injection Combined Vemurafenib Therapy in the Long-term Management of Orbital Involvement of Erdheim-Chester Disease.

Abstract Purpose: To report a rare case of vision loss from Erdheim-Chester Disease (ECD) and long term, follow up, management and results. Case Report: A 62-year-old woman presented with bilateral exophthalmos and deterioration in visual acuity of both eyes. Magnetic resonance imaging studies revealed bilateral intraconal orbital tumors. She was diagnosed optic neuropathy in both eyes. The patient was treated with pegylated interferon and systemic pulse steroid. However, recurrences were common. Subsequently, the patient underwent regular corticosteroid injection directly into the retro-orbital region of both eyes monthly, which led to intermittent improvement of vision. At the 8th month of visual impairment, Vemurafenib was initiated. Results: The visual acuity and visual field scores were stable for 6 years during the follow-up. No major complication was observed. Conclusion: Combined vemurafenib and perioculer steroid injection is a well tolerated therapy with less systemic adverse effects which may benefit patients with orbital involvement of ECD. Key words: Erdheim–Chester disease; compressive optic neuropathy; vemurafenib; Optical coherence tomography; Optical coherence tomography angiography.

Effects of MMP2 and its inhibitor TIMP2 on DNA damage, apoptosis and senescence of human lens epithelial cells induced by oxidative stress.

Oxidative stress-induced lens epithelial cells (LECs) death plays a pivotal role in pathogenesis of age-related cataract (ARC), causing significant visual impairment. Apoptosis of porcine granulosa cells mediated by MMP2 is linked to DNA damage. The current study aimed to investigate the potential mechanism of MMP2 in DNA damage, apoptosis and senescence of lens epithelial cells caused by oxidative stress. HLE-B3 cells were treated with different doses of H2O2 for 24h, and CCK-8 was used to detect cell viability. Furthermore, western blotting was used to detect the expressions of MMP2, Bcl2, Bax, cleaved caspase3, γ-H2AX, p16, p21, and TIMP2. DCFH-DA staining was used to assess ROS levels. Moreover, EdU staining was used to detect cell proliferation, and flow cytometry was used to detect cell apoptosis. Then, 15A3 immunofluorescence staining and γ-H2AX staining were used to detect DNA damage. In addition, SA-β-gal staining was used to observe cell senescence. The present findings suggest that oxidative stress triggers damage to LECs viability and elevates the expression of MMP2. Furthermore, MMP2 interference attenuates H2O2-induced active damage, apoptosis, DNA damage, and cellular senescence in LECs. Additionally, TIMP2 expression is down-regulated in H2O2-induced LECs, which suppresses the expression of MMP2 induced by H2O2. These findings highlight the crucial role of MMP2 and TIMP2 in the modulation of oxidative stress-induced cellular responses in LECs. Collectively, TIMP2 alleviates H2O2-induced lens epithelial cell viability damage, apoptosis, DNA damage and cell senescence in LECs by inhibiting MMP2.

Investigating Microperimetric Features in Bietti Crystalline Dystrophy Patients: A Cross-Sectional Longitudinal Study in a Large Cohort.

To assess the clinical and genetic characteristics of patients with Bietti crystalline dystrophy (BCD) with a focus on potential of microperimetry in monitoring macular function. A total of 208 genetically-confirmed BCD patients were enrolled in this retrospective study. The patients were categorized into subgroups based on their fundus characteristics (fovea sparing and fovea involved), optical coherence tomography (OCT) findings (presence/absence of retinal pigment epithelium [RPE] or ellipsoid zone [EZ] line at the fovea/parafovea), and genetic profiles (Mis/Mis, Tru/Mis, Tru/Tru). Fixation patterns were analyzed, and macular sensitivity (MS) parameters were compared among different groups. Longitudinal analysis was performed to calculate the annual changes in MS parameters. Correlation between genotype and phenotype were further investigated by analyzing cumulative incidence of vision impairment among different genotypic groups. Patients with well-preserved RPE or EZ at the foveal/parafoveal region exhibited higher MS. Notably, there was a decline in sensitivity parameters, with a decrease of -2.193dB/year (95% confidence interval [CI] -4.292 to -0.095, P = 0.041) at the fovea and -1.353dB/year (95% CI -2.047 to -0.659, P < 0.001) in average sensitivity. An age-adjusted comparison of sensitivity among genotypic groups and cumulative incidence analyses showed no association between genotypic groups and vision loss. Microperimetry proves to be one of a credible tool for detecting macular functional changes in BCD patients. BCD patients with different genotypes may have similar disease progression.

Association Between Fatty Liver Index and Incidence of Cataract Surgery in Individuals Aged 50 Years and Older Based on the Korean National Health Insurance Service-Health Screening Cohort (NHIS-HEALS) Data: Longitudinal Retrospective Cohort Study.

Cataract is a leading cause of vision impairment. Obesity-related risk factors, including insulin resistance, increase the risk of cataract. The fatty liver index (FLI) is a biomarker for noninvasive fat layer prediction of nonalcoholic fatty liver disease. The FLI has been used to evaluate the metabolic contribution in other organs besides the eye. However, no study exists on the FLI and eye disease. This retrospective cohort study for the association between the FLI and incidence of cataract surgery in individuals older than 50 years was designed to show that a higher FLI is associated with an increased incidence of cataract surgery in individuals aged 50 years and older. This study was retrospectively designed based on the Korean National Health Insurance Service-Health Screening Cohort (NHIS-HEALS) cohort (median follow-up of 9.8 years). Participants were assigned to 1 of 3 groups based on the FLI: low (FLI<30), intermediate (FLI 30-59), or high (FLI≥60). Kaplan-Meier survival analysis was performed on the cumulative incidence of all-cataract and senile-cataract surgery. Multivariable Cox proportional hazards regression models were used to study the association between the FLI group and cataract surgery after adjusting for potential confounders. Of the 138,347 included participants, the incidence of cataract surgery was 12.49% (4779/38,274), 13.95% (6680/47,875), and 14.16% (7496/52,930) in the low, intermediate, and high FLI groups, respectively. After adjusting for all confounding factors, hazard ratios (HRs; 95% CIs) in the high FLI group for all-cataract surgery were 1.111 (1.028-1.199) and 1.184 (1.101-1.274) in men and women, respectively, when compared with the low FLI group. HRs (95% CIs) in the high FLI group for senile-cataract surgery were 1.106 (1.022-1.197) and 1.147 (1.065-1.237) in men and women, respectively, when compared with the low FLI group. The project was conducted between August 2023 and February 2024 without donations from external bodies. Individuals with a higher FLI had a higher risk of all-cataract surgery. This association was maintained even after limiting the analyses to senile-cataract surgery.

Mapping gaps and exploring impairment and disability prevalence in South Asian (SAARC) countries: a scoping review

Despite the considerable health and economic burden of disability in the South Asian (SA) region, there is limited evidence of impairments and disabilities prevalence and the need for Assistive Technologies (ATs). This scoping review aims to synthesise the evidence of the impairments and disabilities in SA countries. This review followed Arksey and O’Malley’s methodological framework. EBSCOhost, EMBASE, PubMed, and Web of Science databases were searched for original research articles from SA countries. In this study, impairment and disability refer to functional limitations restricting individuals from performing activities, including visual, hearing, speaking, cognitive, mobility, and self-care difficulties. The review included full-text, English-language articles addressing any impairment and disability, without restrictions on publication date. This review identified 105 articles distributed over the six impairment and disability domains: visual, hearing, mobility, self-care, speaking, and cognitive. Most evidence originated from India (50.5%) and focused on visual impairments (53.3%). The review identified that heterogeneity in methodologies, case identification definitions, and study settings contributed to variations in prevalence estimation and restricted the comparability within and across countries. Besides, the uneven distribution of studies across countries suggests varying inclinations of countries toward specific impairment and disability domains. The review identified variations in prevalence due to differences in methodologies, definitions, and contexts. The review also identified the uneven distribution of studies, limited evidence on ATs, reliance on self-reported data, and lack of nationally representative research. Future research should use standardised case identification and evidence-based approaches to enhance comparability and minimise response biases.

Role of epigenetics in corneal health and disease.

Epigenetics plays a vital role in corneal health and diseases. Epigenetic changes regulate the expression of genes by altering the accessibility of chromatin via histone modifications, DNA methylation and miRNAs without altering DNA sequence. Ocular trauma and infections are common causes of corneal damage, vision impairment, and mono/bilateral blindness worldwide. Mounting literature shows that epigenetic modifications can modulate corneal clarity, function, and pathogenesis including inflammation, wound healing, fibrosis, and neovascularization. Additionally, epigenetic modifications can be targeted to reverse corneal pathologies and develop interventional therapies. However, current understanding on how epigenetic modifications lead to corneal abnormalities and diseases is limited. This review provides in-depth knowledge and mechanistic understanding of epigenetics alterations in corneal pathogenesis, and information on potential epigenetic targets for treatment of corneal diseases.