Background:Many clinical techniques exist to quantify the magnitude of heterophoria in free space. In this article, we determine the agreement between the modified Thorington test and three different tests for dissociated heterophoria at near distance in free space. Methods:The modified Thorington, Maddox rod, von Graefe and alternate cover tests were performed on 49 university students at near distance in free space. The 95% limits of agreement between the modified Thorington and other tests were compared in pairs by using the Bland-Altman statistical test. Results: While the Maddox rod-modified Thorington pair showed narrow 95% limit range (2.5 to -3.34 Conclusion:The modified Thorington test cannot be interchanged with the other three near tests for heterophoria in free space. The accuracy in the measurement and the different methods of dissociation may play a crucial role in comparisons of the different tests for heterophoria.

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Purpose: To evaluate the performance of Plusoptix A09 in detecting ametropia, warranted against frequently-used technique of retinoscopy in children attending school (5–15 years) and its probability as a screening tool. Methods: This study was the subset of a larger epidemiological study visual acuity refractive error squint conducted in schools to determine the prevalence of ocular morbidity among the 5–15 years' school children population. Every 7 th student in the class (each school had mean value of 100 students) was randomly selected for this study after ascertaining their eligibility as per the inclusion criteria. A cohort of a total of 150 children within the age group of 5–15 (mean, 10.21 ± 2.83) years were recruited from 11 schools of Udupi district. Students with best corrected visual acuity of 20/20, refractive error within ±5.00 diopter (D), without any eccentric fixation, and no history of ocular pathology or seizures were recruited. Refractive error was tested by Plusoptix photorefractor followed by non-cycloplegic and cycloplegic retinoscopic techniques. The examiners performing these tests were masked and unware of the findings. Bland Altman plotted the agreement between the techniques, followed by the receiver operating characteristic curve (ROC), and sensitivity of Plusoptix. Results: One-way analysis of variance calculated statistical differences among Plusoptix, objective retinoscopy, and cycloplegic retinoscopy for mean spherical value (1.12 ± 1.16 D, 0.65 ± 0.69 D, and 0.8 ± 0.82 D), cylindrical value (−0.83 D ± 1.27, −0.32 D ± 0.86, and −0.34 D ± −0.93), and spherical equivalent value (0.71 D ± 1.06, 0.45 D ± 0.7, and 0.61 D ± 0.81), with P = 0.0001, 0.0001, and 0.097, respectively. Bland Altman plots showed good agreement for spherical equivalent values of Plusoptix and objective retinoscopy. However, the area under the ROC curve (0.386) suggests that lower diagnostic ability of this device in this age group population in comparison to retinoscopy (0.575) with the sensitivity and specificity of Plusoptix was 69.2% and 84.8%. Conclusions: This study fails to report ideal sensitivity mandated for a screening tool, although good specificity and agreement are observed. Along with retinoscopy, this tool will be effective in screening a children's population aged between the age group of 5 and 15 years.

Purpose: To observe the inter-rater reliability between the observers for visual acuity, refractive error, corneal reflex, and inter-pupillary distance. Methods: A random subset of 50 students from primary (1st to 4th grade), higher primary (5th to 7th grade) and secondary school (8th to 10th grade), for a total of 150 students were selected by stratified sampling from the prevalence study VARES (Visual acuity, refractive error, and squint) performed among 1752 school children of Udupi district, India in 2013-2014. The Institutional Ethical Committee & District Health Administration board permission was acquired. There were two examiners: Examiner 1 (JT), a qualified optometrist with two years of experience, and Examiner 2 (MT), an optometry student. Examiners 1 and 2 performed a single measurement for visual acuity using the COMPlog computerized logMAR vision chart at 3 metres; Landolt C or Sloan letter optotypes used. Refractive error, corneal reflex, and inter-pupillary distance was measured by Plusoptix Power-refractor twice by Examiner 1 and thrice by Examiner 2; the average of each value was considered for analysis. Data was tested for normality using the Kolmogorov-Smirnov test. Statistical significance was considered p < 0.05. The agreement between the observers for the two procedures was traced by a Bland-Altman plot. Results: The mean age of the students was 10.21 years (± 2.80 SD). The measurement of agreement for visual acuity (COMPlog) between the examiners was tested using Kappa statistics with 0.79 for OD, p < 0.05 and 1.0 for OS, p < 0.05 supported by Wilcoxon sign rank test showing 0.067 for OD and 0.564 for OS between the observers. The Bland-Altman plot also showed good agreement between the observers. Paired t-test for refractive error showed 0.117 (CI: -0.11­–0.10) for OD & 0.067 (CI: -0.005–0.157) for OS, with Bland-Altman plot showing good agreement between the observers. Paired t-test showed 0.323 for corneal reflex and 0.520 for inter-pupillary distance. Conclusion: From the results we report that there is no interobserver variability for visual acuity, refractive error, corneal reflex and inter-pupillary distance in school screening with COMPlog and Plusoptix A09.

AIM:The aim of this study is to estimate the prevalence of visual impairment among school-going children in Udupi district, Karnataka.MATERIALS AND METHODS:A cross-sectional study across eleven schools from both urban and rural parts of Udupi taluk was conducted to report the magnitude of visual impairment among the schoolchildren. Complex survey design was used in allocating the sample size through stratification and clustering. Totally 1784 schoolchildren between the age groups of 5 and 15 years participated in the study. Presenting visual acuity and objective refraction was measured using computerized logMAR acuity charts and Plusoptix A09 photorefractor, respectively. Manifest ocular deviation or squint was also recorded.RESULTS:The mean age of the students was found to be 10.62 ± 2.72 years. The prevalence of visual impairment, i.e., visual acuity worse than or equal to 20/40 in the better eye was found to be 4.32% (95% confidence interval: 3.38%, 5.26%). The prevalence rate was significantly higher among students from urban area (5.6%) compared to those from rural area (3.6%) (P = 0.011).CONCLUSION:Visual impairment was found to be 4.32% in the school-going population of Udupi district. Effective and user-friendly devices aided the visual deficit screening including refractive error and squint.