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OBJECTIVE: To assess the impact of DIMS (defocus incorporated multiple segments) spectacle lenses on the quality of life of children using it. METHODS: Separate in-depth interviews were conducted with children using DIMS as a myopia control strategy for at least 1 month and their parents based on prepared guides. The recorded audio of the interviews was transcribed, and the significant data points were coded using a hybrid approach, that is, both the inductive and deductive coding methods were used to identify themes. The generated codes were further grouped, categorised and finally fitted as per relevance into the subdomains of the four domains of the WHO Quality of Life-Brief framework, namely the domains of social relationships, physical, psychological and environmental health. RESULTS: A total of 29 interviews were conducted, 15 with children (mean age: 12.47±2.13 years) and 14 with parents. Thematic analysis was done and a total of 63 codes were generated with 2, 16, 17 and 28 codes aligning to the domains of social relationships, environmental, psychological and physical health, respectively. Most parents did not notice any change in their child's visual behaviour, yet children did experience symptoms such as peripheral blurred vision, eyestrain, headache, haloes and more during the adaptation period. High-cost, scratch-prone nature and difficulty in procurement were a few concerns raised by parents. CONCLUSIONS: Participants were satisfied with most of the facets of social relationships, physical and psychological health domains. However, a few facets such as quality, accessibility and finance of the environmental health domain need improvement.
Subject(s)
Eyeglasses , Myopia , Qualitative Research , Quality of Life , Humans , Quality of Life/psychology , Child , Female , Male , Myopia/psychology , Myopia/therapy , Adolescent , Parents/psychology , Visual Acuity , Surveys and QuestionnairesABSTRACT
The evolution of digitally based pedagogies, such as extended reality (XR) - a group of simulated learning environments that include virtual simulation, virtual reality, and augmented reality - has prompted optometry educators to seek evidence to guide the implementation of these teaching and learning activities within their curricula. Looking more broadly across the medical and allied health fields, there is a wealth of evidence to guide the incorporation of XR, as it is increasingly being integrated into the curricula of other select health professions disciplines. Educators from these disciplines continue to explore and embed XR in practice. This narrative review summarises the findings and appraises the literature on the use of XR in optometry education. It identifies the learning domains in which XR has been implemented in optometry education and proposes areas for further investigation. The review questions the technology-focused approach that has driven the literature within the review and calls for richer pedagogical foundations with suggestions for future research agendas. As such, this narrative review provides optometry educators with new ways of understanding XR and its relationship with the curriculum.
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SIGNIFICANCE: This study used behavior change models to understand the perspectives of falls among patients with visual impairment who are at greater risk of falls. Resulting themes on barriers and facilitators led to the identification of a "SMART" intervention strategy that remains to be tested as a fall-reducing behavior. PURPOSE: This study explored the perspectives of adults with visual impairment on falls and proposed falls prevention strategies using behavior change models. METHODS: Participants 18 years or older who were diagnosed with low vision or blindness from a tertiary eye hospital in India and had a history of falls in the previous year were recruited. "Reduction of falls" was defined as a behavior, and interview questions were designed to explore awareness, context, and consequences of falls to determine barriers and facilitators that could help reduce falls. The interviews were audio-recorded, transcribed, translated into English, and analyzed using thematic analysis. The results were linked to the Theoretical Domains Framework and the Behavior Change Wheel, under different levels of a The Socio-Ecological Model. Intervention functions from the Behavior Change Wheel were identified using the APEASE criteria (affordability, practicability, effectiveness/cost-effectiveness, acceptability, safety/side effects, and equity) to finalize behavior change techniques. RESULTS: Themes on barriers and facilitators at individual, family, and societal levels were identified from 36 semistructured telephone interviews. Key barriers were fear of falling, social stigma and lack of training in using assistive devices, not considering falls as a major concern, environmental hazards, and loss of support from caregivers. Key facilitators were consciously monitoring falls, undergoing orientation and mobility training, getting assistance for outdoor mobility, and self-confidence. CONCLUSIONS: This study proposed a five-step "SMART" intervention strategy for prevention of falls to be prospectively tested. SMART include Support from caregivers and use of assistive devices, Monitoring of falls, Awareness about falls, Reduction of hazards, and Training for safe mobility.
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Vision, Low , Adult , Humans , Fear , Blindness , IndiaABSTRACT
Purpose: Center-surround contrast suppression-typically induced when a center pattern is surrounded by another pattern with similar spatial features-is considered a perceptual analogue of center-surround neurophysiology in the visual system. Surround suppression strength is altered in a range of brain conditions affecting young people (e.g., schizophrenia, depression, migraine) and is modulated by various neurotransmitters. The early teen years are associated with neurotransmitter changes in the human visual cortex, which could impact on excitation-inhibition balance and center-surround antagonistic effects. Hence, we predict that early adolescence is associated with perceptual changes in center-surround suppression. Methods: In this cross-sectional study, we tested 196 students at every age from 10 to 17 years and 30 adults (aged 21-34 years) to capture the preteen, adolescent, and adult periods. Contrast discrimination thresholds were measured for a central, circular, vertical sinusoidal grating pattern (0.67° radius, 2 cyc/deg spatial frequency, 2 deg/s drift rate) with and without the surround (4° radius, otherwise same spatial properties as the center). Individual suppression strength was determined by comparing the perceived contrast of the target with and without the surround. Results: After excluding unreliable data (7% of total), we found an effect of age on perceptual center-surround contrast suppression strength, F(8,201) = 2.30, P = 0.02, with weaker suppression in the youngest adolescents relative to adults (Bonferroni pairwise comparisons between adults vs 12-year-olds P = 0.01; adults vs 13-year-olds P = 0.002). Conclusions: Our data demonstrate different center-surround interactions in the visual system-a key building block for visual perception-in early adolescence relative to adulthood.
Subject(s)
Contrast Sensitivity , Visual Cortex , Adult , Humans , Adolescent , Child , Cross-Sectional Studies , Photic Stimulation , Visual Perception/physiology , Visual Cortex/physiology , Neurotransmitter AgentsABSTRACT
BACKGROUND: Inherent features in virtual simulation could be utilised to deliver collaborative global education that is inclusive, accessible, and valued by students and facilitators. The aim of this study was to evaluate the impact of the International Eyecare Community (IEC) platform's virtual simulated international placements (VSIP) in optometric education. METHODS: An international, multi-center, cross-sectional mixed methods study with Deakin University, Australia, and the Elite School of Optometry, India, was used to evaluate the impact of VSIP in the IEC using pre-existing deidentified data collected from teaching and learning activities within the optometry course curriculum. Data on students and facilitators perceptions of the VSIP were collected through deidentified transcripts from focus group discussions. The data were interpreted using descriptive statistics and qualitative analysis using constant comparison for thematic analysis. RESULTS: A total of 64 out of 167 student participants completed survey responses (39%) and 46 out of 167 (28%) completed self-reflective inventories. Focus groups with 6 student participants and 6 facilitator participants were recorded and analysed. Student participants reported the IEC was relevant (98% agreement) and motivated them to apply theoretical knowledge to a clinical context (97% agreement). The themes identified through qualitative analysis were: factors inherent to the virtual simulation that enabled learning through VSIP, the VSIP supported cognitive apprenticeship, VSIP enabled clinical learning for optometric education, VSIP' role in cross-cultural professional identity development in optometry students. CONCLUSION: The study found that the VSIP platform helped to motivate students to learn and improve their clinical skills. The VSIP was considered a potential supplement to physical clinical placements and could revolutionize global optometric education by offering co-learning across cultures.
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Curriculum , Students , Humans , Cross-Sectional Studies , Australia , LearningABSTRACT
PURPOSE: To provide the prevalence of vision impairment and blindness among 250,000 school children aged 6 to 17 years, screened in Tamil Nadu, India. METHODS: The study was conducted between 2016 and 2019 as a part of the school eye screening program in Kanchipuram district, Tamil Nadu. The clinical examination included basic vision testing, objective refraction, subjective acceptance, spectacle dispensing, and a posterior segment evaluation. The prevalence of vision impairment, blindness, low vision, and the association with other demographic variables using logistic regression were calculated. RESULTS: A total of 250,052 children were screened in 1047 schools and the prevalence of vision impairment, blindness, and low vision in Kanchipuram district was 3.83%, 0.01%, 0.19%, respectively. The major causes for vision impairment, blindness, and low vision were refractive errors (3.05%), high myopia (0.002%), and refractive amblyopia (0.04%), respectively. Vision impairment was significantly associated with urban location (OR = 1.42, 95% CI 1.36-1.48, p < .0001), females (OR = 1.11, 95%CI - 1.08-1.15, p < .0001), private schools (OR = 2.43, 95%CI - 2.35-2.42, p < .0001), higher secondary class grade (OR = 1.69, 95%CI - 1.61-1.77, p = .001), high-school class grade (OR = 1.65, 95%CI - 1.58-1.72, p = .001) and middle school class grade (OR = 1.53, 95%CI - 1.47-1.59, p = .001). CONCLUSION: This large-scale school eye screening reports a comparatively lower prevalence of vision impairment, blindness, and low vision when compared to other studies conducted around the world. Although the overall prevalence is relatively low, the causes are mostly refractive. Urban, female, private school-going children aged 11-17 are at higher risk.
Subject(s)
Refractive Errors , Vision Screening , Vision, Low , Humans , Child , Female , Visual Acuity , Vision, Low/epidemiology , India/epidemiology , Cross-Sectional Studies , Refractive Errors/epidemiology , Blindness/epidemiology , Prevalence , Vision Screening/methodsABSTRACT
PURPOSE: The purpose of this study is to report the distribution of astigmatism among school children in South India. METHODS: The study was conducted as part of a national school eye screening project named 'Refractive Error Among Children' (REACH) between 6 and 17 years of age. Children underwent presenting visual acuity screening, external eye examination, screening for color vision deficiency, and non-strabismic binocular vision anomalies. Those who failed screening underwent, objective and subjective refraction, and identification of other ocular conditions. Astigmatism was defined as cylindrical power greater than 0.50D. Refractive errors were classified into myopia (≤0.50D), hyperopia (≥0.75D), and other refractive errors (between -0.50D and +0.75D). The data on astigmatism were analyzed and were deduced into its vector components (M, J0 and J45). Descriptive statistics and regression analysis were performed. RESULTS: Data of 245,565 children from 1047 schools were taken for analysis. The average age was 11.63 ± 3.32 (range:6-17) years. After screening, refractive errors and astigmatism was found to be 6.57% (n = 16157) and 3.69% (n = 9064), respectively. Astigmatism among children aged 6 to 10 years was 1.37%. The mean cylindrical power, J0, and J45 was found to be 1.93 ± 1.06D, 0.06 ± 0.59D, and 0.43 ± 0.81D, respectively. Linear regression showed a decreasing trend in the cylindrical component (p < .001) and shift towards less positive J0 values (p < .001). Higher proportions of astigmatism more than 1.50 D (1.83%,n = 4578) and unilateral astigmatism (1.20%,n = 2952) are evident among refractive errors. CONCLUSION: More than 50% of children who failed vision screening with refractive errors presented with astigmatism. Prevalence was higher among primary school children. Presence of higher magnitude and unilateral astigmatism is amblyogenic and needs early intervention.
Subject(s)
Astigmatism , Refractive Errors , Vision Screening , Child , Humans , Adolescent , Astigmatism/epidemiology , Refractive Errors/epidemiology , Visual Acuity , Prevalence , IndiaABSTRACT
Objectives: Axial length (AL) is an important contributor to refraction, and growth curves are gaining importance in the prediction of myopia. This study aimed to profile the distribution of ocular biometry parameters and to identify correlates of spherical equivalent refraction (SE) among school children in South India. Materials and Methods: The School Children Ocular Biometry and Refractive Error study was conducted as part of a school screening program in southern India. The enrolled children underwent tests that included vison check, refraction, binocular vision assessment, and biometry measurements. Results: The study included 1382 children whose mean (standard deviation [SD]) age was 10.18 (2.88) years (range: 5-16 years). The sample was divided into 4 groups (grades 1-2, grades 3-5, grades 6-9, and grade 10) based on significant differences in right AL (p<0.001). The mean (SD) AL (range: 20.33-27.27 mm) among the four groups was 22.50 (0.64) mm, 22.88 (0.69) mm, 23.30 (0.82) mm, and 23.58 (0.87) mm, respectively. The mean SE (range: +1.86 to -6.56 D) was 0.08 (0.65 D) in class 1 and decreased with increasing grade to -0.39 (1.20 D) in grade 10. There was a significant difference in all biometry parameters between boys and girls (p<0.001). Age, AL, and mean corneal curvature were the main predictors of SE. Conclusion: This study provides a profile of ocular biometry parameters among school children in South India for comparison against profiles from other regions across the country. The study data will form a reference for future studies assessing myopia in this ethnicity.
Subject(s)
Myopia , Refractive Errors , Male , Female , Humans , Child , Child, Preschool , Adolescent , Refractive Errors/diagnosis , Refractive Errors/epidemiology , Refraction, Ocular , Myopia/diagnosis , Biometry/methods , India/epidemiologyABSTRACT
PURPOSE: School eye screening is a crucial strategy in the elimination of childhood blindness because of its ability to reach out to children who are otherwise inaccessible to eye care needs. Comprehensive screening programs are recommended and are beneficial, but the economic aspects of such models remain to be understood. This study aimed to analyse the cost of a comprehensive school eye screening model while utilizing optometrists and optometry students. METHODS: This cross-sectional study was conducted for 295 schools screened in the academic year 2018-2019. The analysis was performed from the service provider's perspective including only the direct costs. Financial records were used for cost estimates. The outcome measures were cost per school and child, predictors for the cost, DALYs averted, cost of childhood blindness, and Benefit-Cost Ratio. RESULTS: A total of 65 094 children underwent screening from 295 schools. The median (IQR) cost per school and child for screening was $29.65 (29.65-44.34) and $0.66 (0.32-1.13). The regression model predicted that the cost of screening was dependent on school strength, number of screening personnel, distance of the schools, and deliverables. With the interventions to improve compliance, 14686.30 DALYs have been averted. Loss of productivity due to childhood blindness was estimated to be $339070.83. Screening for colour vision also had a Benefit-Cost ratio of greater than one. CONCLUSION: Cost of screening was low and the benefits were high while utilising optometrist and optometry students along with a comprehensive screening protocol.
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Purpose: To present the eye care seeking behavior among rural adults in South India. Methods: This cross-sectional study was conducted between 2019 and 2020 covering three blocks of the Thiruvannamalai district, Tamil Nadu, India. Door-to-door survey was performed to collect demographic information, status of literacy, occupation, and details of previous eye examination. Distance visual acuity was tested for individuals available in the house using a log MAR (logarithm of minimum angle of resonance) chart. Association between demographic details, details of previous eye examination, and status of vision was analyzed using logistic regression. Results: A data of 12,913 individuals were included for the analysis, of which 6460 (50.03%) were females. Of the total individuals, 2007 (15.54%) had undergone an eye examination previously. There were 1639 (28.50%) people who had a vision less than 0.2 log MAR in at least one eye. The odds of reported 'previous eye examination' were more among females [odds ratio (OR) 1.48, 95% confidence interval (CI): 1.32-1.66, P < 0.001]; individuals aged above 60 years [OR: 11.46, 95% CI: 9.44-13.91, P < 0.001], between 40 and 60 years [OR: 10.43, 95% CI: 8.85-12.30, P < 0.001], and between 18 and 40 years [OR: 2.48, 95% CI: 2.16-2.84, P < 0.001]; illiterates (OR: 1.76, 95% CI: 1.45-2.15, P < 0.001); and farmers (OR: 1.32 95% CI: 1.12-1.55, P = 0.001). Conclusion: The study presents the utilization of eye care among rural South Indian adults. Almost 84.46% of individuals had not undergone any eye examination. Robust measures to promote eye care management would help in effective utilization of eye care services among rural adults.
Subject(s)
Patient Acceptance of Health Care , Rural Population , Adult , Aged , Cross-Sectional Studies , Female , Humans , India , Male , Prevalence , Visual AcuitySubject(s)
COVID-19 , Optometry , Asia/epidemiology , COVID-19/epidemiology , Humans , Pandemics , SARS-CoV-2ABSTRACT
Purpose: To profile the presentation of ocular conditions among school children aged 6 to 17 years from the south Indian state of Tamil Nadu. Methods: The study was conducted as part of a school eye health program in Kanchipuram district, Tamil Nadu that aimed to address the refractive needs of children (6-17 years) between July 2016 and June 2019. The study followed a three-phase protocol, which included visual acuity test, modified clinical test, color vision test, binocular vision assessment, objective and subjective refraction, dispensing spectacles, posterior segment evaluation using direct ophthalmoscopy, and referral to the base hospital. The demographics, clinical details, and ocular conditions (classified under 16 categories) were analyzed. Profiling and association of ocular conditions among different locations, types of schools, class grades, and gender were presented. Results: Data of 2,45,565 children were analyzed from 1,047 schools, of which 4,816 (1.96%) children were identified with ocular conditions other than refractive errors. The common reasons for referral were high myopia 901 (0.37%), strabismus 819 (0.33%), and amblyopia 691 (0.28%). Retinal problems (odds ratio [OR]: 1.65, 95% confidence interval [CI]: 1.22-2.22, P = 0.001) and strabismus (OR: 1.41, 95% CI: 1.21-1.65, P < 0.001) were the conditions prevalent in the rural location. Cataract and related conditions (OR: 5.73, 95% CI: 4.10-8.01, P < 0.001) and retinal problems (OR: 4.76, 95% CI: 3.37-6.72, P < 0.001) were common in children studying in public schools. Of the 16 categories, 13 conditions were seen among primary school children. Vernal keratoconjunctivitis (OR: 3.64 95% CI: 2.12-6.23 P < 0.001) was common among males. Conclusion: The study profiled ocular conditions among school children. Most ocular conditions warrant prolonged care and specialty eye care services. Ensuring the availability of such services and follow-up after school eye screening would safeguard the visual development of these children.
Subject(s)
Myopia , Strabismus , Child , Female , Humans , India/epidemiology , Male , Prevalence , Visual AcuityABSTRACT
Purpose: Impact of color vision deficiency (CVD) on activities at school and productivity at work and consequential psychosocial difficulties has been reported. Although early detection and awareness help in overcoming these difficulties, screening for CVD is not a part of the school eye-screening initiatives in many countries. This study aimed at reporting the prevalence of CVD among school-going boys in Kanchipuram district, South India. Methods: The study was carried out as part of a school eye-screening program (SES) conducted in Kanchipuram district, Tamil Nadu, India for children between 6 and 17 years. The SES followed a three-phased protocol, which also included screening for CVD for all the boys between 11 and 17 years. The boys underwent CVD screening with Dalton's pseudo isochromatic plates (PIPs) followed by confirmation with Ishihara's PIP. The data were analyzed and the proportion of CVD in boys among different class grades, type of schools, location of schools, blocks of the district, and other clinical characteristics are presented. Results: Totally 250,052 children were screened in 1047 schools of which 74986 (60.61%) were boys between 11 and 17 years (mean age: 13.75 ± 1.91). The overall prevalence of CVD was found to be 2.76% (n = 2073; 95% confidence interval [CI]: 2.65-2.88). CVD was associated with urban locations (3.17% odds ratio [OR]: 1.90 95%CI: 1.69-2.13 P < 0.05) and public schooling (2.87%) (OR: 1.29 95%CI: 1.17-1.43 P < 0.05). Boys with CVD were less likely to have vision impairment (P = 0.002) and myopia (P < 0.001) as compared with boys with normal color vision. There was no significant difference in the proportion of other ocular conditions between children with and without CVD (P > 0.05). Conclusion: The study shows a significant proportion of CVD among boys in Kanchipuram district, India and its association with various demographic and clinical characteristics. Identification of CVD and counseling the stakeholders earlier through school children screening is crucial.
Subject(s)
Color Vision Defects , Vision Screening , Adolescent , Child , Color Vision Defects/diagnosis , Color Vision Defects/epidemiology , Cross-Sectional Studies , Humans , India/epidemiology , Male , Prevalence , SchoolsABSTRACT
Purpose: To define the prevalence of visual impairment, refractive errors and other ocular problems among school children from the public schools of South India between 2011 and 2015.Methods: This was a cross-sectional study covering 296 schools in the three districts of Tamil Nadu. The school eye screening included visual acuity assessment, external eye examination, objective and subjective refraction, and direct ophthalmoscopy. Vision impairment was defined as logMAR visual acuity of less than 0.2 (Snellen equivalent of 6/9).Results: A total of 91545 children were included with a mean age of 12.9 ± 3.0 years. The prevalence of vision impairment was found to be 5.67% (95%CI 5.53-5.83) and spherical equivalent refractive error was 4.42% (95%CI 4.29-4.56). The prevalence of myopia, hyperopia, and 'other refractive errors' was found to be 3.57% (95%CI 4.01-4.27), 0.03% (95%CI 0.02-0.04), and 0.82% (95%CI 0.76-0.88) respectively. Strabismus, retina and neuro-ophthalmology-related abnormalities, ptosis, and corneal scars were the common ocular problems. In the rural region the prevalence of the refractive errors and the ocular problems were 2.92% and 2.32%, respectively.Conclusion: The study reports a lower prevalence of refractive errors and myopia in this population, much lesser compared to other reported studies from India. Rural regions exhibit an equal need for both refractive services and management of other ocular problems.
Subject(s)
Refractive Errors , Adolescent , Child , Cross-Sectional Studies , Humans , India/epidemiology , Prevalence , Refraction, Ocular , Refractive Errors/diagnosis , Refractive Errors/epidemiology , Schools , Visual AcuityABSTRACT
Purpose: Global trends show a high prevalence of refractive errors among children. The prevalence of vision impairment due to uncorrected refractive errors among school children is increasing and the need for management of other ocular conditions is also reported. This study presents the status of eye health and pattern of daily activities among the school children of a tribal location in Tamil Nadu, South India. Methods: A cross-sectional study was conducted in 13 schools of Karumandurai cluster, Salem district in Tamil Nadu, India. A three-phased comprehensive school screening protocol was conducted to understand the prevalence of vision impairment, refractive error, and other ocular conditions along with a survey about the daily activities of the children at school and home. Results: Among the 3655 children screened, the prevalence of vision impairment was found to be 0.62% (n = 23, 95% confidence interval [CI] 0.42-0.94) and prevalence of refractive error was 0.30% (n = 11, 95%CI 0.17-0.54), among which 0.11% (n = 4) were already wearing spectacles. A total of 44 children (1.20%; 95%CI 0.90-1.61) were found to have other ocular problems and among them, 14 (0.38%) had visual acuity less than 20/30 (6/9). Almost 84% of children required surgical or specialty eye care services. Vision impairment was more in children with other ocular conditions compared to refractive errors (P < 0.001). Conclusion: The prevalence of vision impairment and refractive errors in this tribal area was less. Ocular conditions were more prevalent than refractive errors in this tribal region with the majority of children needing specialty or surgical eye care services. This implies the need for access to secondary or tertiary eye care centers.
Subject(s)
Refractive Errors , Child , Cross-Sectional Studies , Humans , India/epidemiology , Prevalence , Refractive Errors/epidemiology , Schools , Visual AcuityABSTRACT
SIGNIFICANCE: This study explains the construction and validation of a chart in Hindi language, one of the commonly spoken languages in the world. The new visual acuity chart is called LEA Hindi chart. The calligraphy construction method described here can help develop other such acuity charts. PURPOSE: The purpose of this study was to construct and validate a new logMAR Hindi visual acuity chart (LEA Hindi chart) using principles similar to that of LEA symbols acuity chart. METHODS: A multicenter (three centers) study was conducted in two phases. The first phase consisted of identifying and constructing the Hindi optotypes using calligraphy techniques. The Hindi optotypes were calibrated against the Landolt C optotypes by measuring the threshold distance for visual acuity. In the second phase, the newly constructed LEA Hindi chart was validated against the Early Treatment Diabetic Retinopathy Study (ETDRS) and Landolt C visual acuity charts. Sixty participants were enrolled for the first phase (centers 1 and 2) and for the second phase of the study (centers 1 and 3). Additional 15 participants were enrolled (center 1) for testing repeatability. RESULTS: Four Hindi optotypes were identified and used for the construction of the chart (first phase). In the second phase, the LEA Hindi chart was found to be comparable with both the Landolt C, (logMAR acuity difference, 0.03 ± 0.13; P > .18) and ETDRS (logMAR acuity difference, -0.02 ± 0.09; P > .25) charts. All the three charts were also found to be repeatable (95% limits of agreement within 0.24 logMAR). CONCLUSIONS: The newly constructed LEA Hindi visual acuity chart gave comparable levels of visual acuity as that measured in an ETDRS or Landolt C charts. The repeatability was also similar to the standard charts. The LEA Hindi visual acuity chart can be used for patients comfortable with Hindi language and also in studies requiring multiple measurements of visual acuity, to avoid familiarity to a given chart.
Subject(s)
Language , Vision Tests/instrumentation , Visual Acuity/physiology , Adolescent , Adult , Equipment Design , Female , Humans , India , Male , Middle Aged , Reproducibility of Results , Vision, Low/physiopathology , Young AdultABSTRACT
BACKGROUND: Diagnosing colour vision deficiency is vital, owing to its impact on the choice of career and activities of daily living. Conventional screening methods require frequent replacement due to soiling of the materials, and hence are expensive and not feasible for large-scale community screening. This study aims to construct and validate a new screening tool, Dalton's pseudo-isochromatic plates (PIP), addressing the disadvantages of the conventional methods. METHODS: The two phases of the study included the construction and validation of the Dalton's PIP. Construction involved utilising specific wavelengths based on spectral tuning, selection of numerals as targets for the chart and identification of a material with durability and resistance to wear and tear. Validation of the chart was done against the 38-plate edition of Ishihara's PIP by two masked examiners for 1,019 school children aged between 11-17 years (mean ± SD: 14 ± 2 years) as part of a school eye-health program. RESULTS: The sensitivity and the specificity of the Dalton's PIP was found to be 94.12 per cent (95% CI 71.31-99.85) and 99.60 per cent (95% CI 98.98-99.89) respectively and the positive and negative predictive values were 80 per cent and 99.90 per cent respectively. Dalton's PIP when used with a failure criterion of less than three plates correct in two screening sets had the maximum sensitivity and specificity and the area under the curve was 0.96 (95% CI 0.90-0.99, p < 0.05). CONCLUSION: The newly constructed Dalton's PIP is found to be a valid screening tool to detect congenital colour vision deficiency and is comparable to the Ishihara PIP. This screening tool with its shorter screening time, cost and longer durability would effectively serve in large-scale vision screening programs.