Validity and Reliability of Vis-Screen Application: A Smartphone-Based Distance Vision Testing for Visual Impairment and Blindness Vision Screening.

Background and Objectives: The health-related mobile applications (app) might assist in promoting inclusive health and tele-treatment, especially for the less severe diseases. In this paper, a study had been done to determine the app's reliability in terms of raters and the app's agreement with the Snellen chart. Materials and Methods: A cross-sectional sectional study was conducted between November 2019 and September 2020. Participants were selected via purposive sampling from selected communities in Terengganu state. All participants underwent vision testing with the Vis-Screen app and Snellen chart for validity and reliability accordingly. Results: A total of 408 participants were involved, with a mean age of 29.3. The sensitivity of the presenting vision of the right eye (PVR) ranged from 55.6% to 88.4%, with specificity between 94.7% to 99.3%, while the positive and negative predictive values were between 57.9% and 81.7% and 96.8% and 99.0%, respectively. The positive likelihood ratios ranged between 16.73 and 73.89, whereas the negative likelihood ratios ranged from 0.12 to 0.45. The area under the receiver operating characteristic curve (AUC) for all cut-off points ranged between 0.93 and 0.97, and the optimum cut-off point was at 6/12. The kappa values for intra-rater and inter-rater were 0.85 and 0.75, respectively, while the app's reliability with the Snellen chart was 0.61. Conclusions: Vis-Screen was concluded to be valid and reliable for use as a screening tool for detecting individuals with visual impairment and blindness in the community. A valid and reliable portable vision screener like Vis-Screen will help expand the eye care feasibility while providing similar accuracy as the conventional charts in clinical practices.

Prevalence of refractive error in malay primary school children in suburban area of Kota Bharu, Kelantan, Malaysia.

INTRODUCTION: Refractive error remains one of the primary causes of visual impairment in children worldwide, and the prevalence of refractive error varies widely. The objective of this study was to determine the prevalence of refractive error and study the possible associated factors inducing refractive error among primary school children of Malay ethnicity in the suburban area of Kota Bharu, Kelantan, Malaysia. MATERIALS AND METHODS: A school-based cross-sectional study was performed from January to July 2006 by random selection on Standard 1 to Standard 6 students of 10 primary schools in the Kota Bharu district. Visual acuity assessment was measured using logMAR ETDRS chart. Positive predictive value of uncorrected visual acuity equal or worse than 20/40, was used as a cut-off point for further evaluation by automated refraction and retinoscopic refraction. RESULTS: A total of 840 students were enumerated but only 705 were examined. The prevalence of uncorrected visual impairment was seen in 54 (7.7%) children. The main cause of the uncorrected visual impairment was refractive error which contributed to 90.7% of the total, and with 7.0% prevalence for the studied population. Myopia is the most common type of refractive error among children aged 6 to 12 years with prevalence of 5.4%, followed by hyperopia at 1.0% and astigmatism at 0.6%. A significant positive correlation was noted between myopia development with increasing age (P <0.005), more hours spent on reading books (P <0.005) and background history of siblings with glasses (P <0.005) and whose parents are of higher educational level (P <0.005). Malays in suburban Kelantan (5.4%) have the lowest prevalence of myopia compared with Malays in the metropolitan cities of Kuala Lumpur (9.2%) and Singapore (22.1%). CONCLUSION: The ethnicity-specific prevalence rate of myopia was the lowest among Malays in Kota Bharu, followed by Kuala Lumpur, and is the highest among Singaporean Malays. Better socio-economic factors could have contributed to higher myopia rates in the cities, since the genetic background of these ethnic Malays are similar.