METHODS: A simple visual acuity test algorithm in the form of a single letter E display was designed as the optotype for development of a mobile application. The standardised optotype is presented at random to test visual acuity for corresponding level of 3/60, 6/60, 6/18, and 6/12. The final result is auto-generated based on the classification of the WHO for visual impairment and blindness. The Snellen chart was used as the gold standard to determine its validity while five different users were involved to determine its inter-rater reliability. A pilot study was performed between April till November 2019, in the Universiti Sultan Zainal Abidin Medical Centre (UMC) at Kuala Nerus and Mooris Optometrist Centre at Marang, Terengganu. A total of 279 participants aged four years old and above were involved in this study.
RESULTS: The highest sensitivity was found at the vision level cut-off point of 6/12 with the percentage of 92.7% and 86.8% for the right and left eye, respectively. The specificity was more than 89% for all vision levels in both eyes. The Krippendorff's alpha value for the inter-rater reliability was 0.87 and 0.83.
CONCLUSION: The relatively high level of validity and reliability obtained indicate the feasibility of using the designed optotype to develop a valid and reliable mobile app for vision test. The app can be used to screen vision by nonmedical persons, at anytime and anywhere to help improve public awareness and capability to correctly determine their visual status.
METHOD: Participants of school-age and adolescent students from Klang Valley School completed the 21-item Malay OCI-CV using Google Form. OCI-CV English version was translated backward and forward to the Malay language. Face validity was conducted first before distributing the questionnaire to the participants. Exploratory Factor analysis (EFA) and Confirmatory Factor Analysis (CFA) was conducted to evaluate the psychometric properties of OCI-CV.
RESULTS: A total of 102 school-age children and adolescents with a mean age of 15.96 years (male: 41.2%, female: 58.8%) participated in the study. The Malay OCI-CV showed high internal consistency, with Cronbach Alpha values of 0.90 for the whole scale. EFA showed multifactorial components. Five factors were labelled as "Washing / Ordering, Doubting, Obsessions, Checking, and Hoarding,". In the CFA, the five-factor model indicates adequate fit indices of (χ2/df = 1.51, RMSEA = .071, GFI = .824, AGFI = .769, NFI = .724, CFI = .880).
CONCLUSION: The Malay OCI-CV has good psychometric properties and is suitable for use in the Malaysian context. Further validation studies should be conducted among a clinical population to enhance the generalization of this finding.