Comparative Study of the Snellen iPad App versus Traditional Light Box Snellen Chart in Distance Visual Acuity

Abstract

This study aimed to the Snellen whether measurements of distance visual acuity using Snellen Chart displayed on iPad tablet is comparable with traditional light-box Snellen Chart among patients in Ophthalmology Outpatient Department by using Snellen iPad application (Eye Chart HD iOS application) as a visual acuity assessment tool. It utilized a cross sectional study design among 100 new patients identified through purposive sampling. Only those who met the criteria (new patients, male or female and aged 8-years-old and above) were included in the study while patients who had a visual acuity of less than 6/30 were not included. Visual acuity was assessed through two testing modalities: (1) The traditional Snellen Light-Box Chart and (2) An iPad Mini 2 with Eye Chart HD iOS application. Findings showed that results of the Snellen iPad application (Eye Chart HD iOS application) and traditional light-box Snellen Chart are comparable with each other. Confounders were also identified such as patient-related factors wherein participants may have memorized the traditional Snellen Chart prior to their eye examination, thereby invalidating the accuracy of the results from the first testing modality employed. Recommendations for future studies include using a larger sample size, exploring the use a paid apps, and controlling the luminous intensity of the iPad Mini 2 and the traditional light-box Snellen Chart to ensure that luminous intensity of each test modality does not affect the validity of the outcome or results of the study.