ABSTRACT
@#algorithm for mobile application and perform a pilot study todetermine its validity and reliability as a tool for vision testin the community.Methods: A simple visual acuity test algorithm in the form ofa single letter E display was designed as the optotype fordevelopment of a mobile application. The standardisedoptotype is presented at random to test visual acuity forcorresponding level of 3/60, 6/60, 6/18, and 6/12. The finalresult is auto-generated based on the classification of theWHO for visual impairment and blindness. The Snellen chartwas used as the gold standard to determine its validity whilefive different users were involved to determine its inter-raterreliability. A pilot study was performed between April tillNovember 2019, in the Universiti Sultan Zainal AbidinMedical Centre (UMC) at Kuala Nerus and MoorisOptometrist Centre at Marang, Terengganu. A total of 279participants aged four years old and above were involved inthis study. Results: The highest sensitivity was found at the vision levelcut-off point of 6/12 with the percentage of 92.7% and 86.8%for the right and left eye, respectively. The specificity wasmore than 89% for all vision levels in both eyes. TheKrippendorff’s alpha value for the inter-rater reliability was0.87 and 0.83.Conclusion: The relatively high level of validity andreliability obtained indicate the feasibility of using thedesigned optotype to develop a valid and reliable mobile appfor vision test. The app can be used to screen vision by non-medical persons, at anytime and anywhere to help improvepublic awareness and capability to correctly determine theirvisual status.
ABSTRACT
<p><b>INTRODUCTION</b>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.</p><p><b>MATERIALS AND METHODS</b>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.</p><p><b>RESULTS</b>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%).</p><p><b>CONCLUSION</b>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.</p>