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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. [ABSTRACT FROM AUTHOR]

Background: Success of a school vision screening program depends on compliance with the advice that is offered to the children. This study evaluates the effect of an intervention package on compliance to spectacle wear and referral in a school vision screening program.Methods: Among 8,442 children aged 13-17 years in 11 government schools in and around Chennai, India, 114 (2.2 per cent) children who required spectacles were allocated to the control arm (5,116 children) and 124 (3.7 per cent) children to the intervention arm (3,326 children). There were 44 (0.9 per cent) children in the control arm and 49 (1.5 per cent) children in the intervention arm who required referral for further management. Control schools received a conventional school screening protocol and intervention schools received 23-step interventions. Spectacle wear was noted in an unannounced direct observation after one, four and 12 months. Compliance to referral was noted based on the response of children with confirmation from medical records.Results: Spectacle compliance was significantly higher for the intervention arm compared to the control arm based on direct observation in the first month (17.6 per cent versus 49 per cent, adjusted odds ratio [OR] = 4.4, 95 per cent confidence interval [CI] 2.3-8.5, p < 0.05); in the fourth month (23 per cent versus 56 per cent, OR = 4.2, 95 per cent CI 2.3-7.8, p < 0.05); and in the 12th month (13.3 per cent versus 38.8 per cent, OR = 4.1, 95 per cent CI 1.8-9.4, p < 0.05). Referral compliance was significantly higher in the intervention arm in the first month (17.5 per cent versus 70.5 per cent, OR = 10.9, 95 per cent CI 3.8-30.9, p < 0.001) and in the fourth month (31.7 per cent versus 75.6 per cent, OR = 6.2, 95 per cent CI 2.3-16.0, p < 0.001).Conclusion: A 23-step package of interventions was effective in improving compliance to spectacle wear and referral among adolescents in a school vision screening program. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to report the minimum test battery needed to screen non-strabismic binocular vision anomalies (NSBVAs) in a community set-up. When large numbers are to be screened we aim to identify the most useful test battery when there is no opportunity for a more comprehensive and time-consuming clinical examination.Methods: The prevalence estimates and normative data for binocular vision parameters were estimated from the Binocular Vision Anomalies and Normative Data (BAND) study, following which cut-off estimates and receiver operating characteristic curves to identify the minimum test battery have been plotted. In the receiver operating characteristic phase of the study, children between nine and 17 years of age were screened in two schools in the rural arm using the minimum test battery, and the prevalence estimates with the minimum test battery were found.Results: Receiver operating characteristic analyses revealed that near point of convergence with penlight and red filter (> 7.5 cm), monocular accommodative facility (< 10 cycles per minute), and the difference between near and distance phoria (> 1.25 prism dioptres) were significant factors with cut-off values for best sensitivity and specificity. This minimum test battery was applied to a cohort of 305 children. The mean (standard deviation) age of the subjects was 12.7 (two) years with 121 males and 184 females. Using the minimum battery of tests obtained through the receiver operating characteristic analyses, the prevalence of NSBVAs was found to be 26 per cent. Near point of convergence with penlight and red filter > 10 cm was found to have the highest sensitivity (80 per cent) and specificity (73 per cent) for the diagnosis of convergence insufficiency. For the diagnosis of accommodative infacility, monocular accommodative facility with a cut-off of less than seven cycles per minute was the best predictor for screening (92 per cent sensitivity and 90 per cent specificity).Conclusion: The minimum test battery of near point of convergence with penlight and red filter, difference between distance and near phoria, and monocular accommodative facility yield good sensitivity and specificity for diagnosis of NSBVAs in a community set-up. [ABSTRACT FROM AUTHOR]