Validating a novel visual field assessment app: A pilot study

Abstract

Introduction The paper Cullen chart has been a validated adjunct to perimeters in detecting scotomas for various neuro-ophthalmological pathologies for decades. It was digitized into a prototype-app to empower future users to conduct remote monitoring of visual fields. This project aimed to refine the apps' usability for future users to self-assess and monitor their visual fields by exploring the difficulties faced using the app, to gather feedback, and subsequently to improve its usability for future iterations to objectively compare iterations using the MAUQ scores. Methods Participants (n = 15; age: 24-58) recruited through convenience sampling underwent mixed (quantitative and qualitative) methods to measure 1. Participants' adherence to the app instruction through observation, 2. objective experiences of using the app through self-reporting using the mHealth App Usability Questionnaire (MAUQ), and 3. Subjective experience of app using through semi-structured interviews. Descriptive analysis was computed for observation and MAUQ data. Thematic analysis was adopted to analyse the semi-structured interview data. Results 1/15 adhered to 3 written instructions and 8/15 participants had awkward hand movements. The MAUQ median score was 123/147, the MAUQ domain mean scores - ease of use and satisfaction, system information arrangement and usefulness were 81.6%(45.7/56), 80.6%(33.9/42) and 80.2%(39.3/49), respectively. Questions 4, 5, 9, 11 and 19 were the 5 lowest-scoring questions. Qualitative data were categorised into instructions, test, and feedback which had codes and subcodes. Conclusion Feedback for improvements were surrounding central fixation, remembering peripheral stimuli, uncover eye when interacting with peripheral stimuli, video examples, an introduction to the app and audio instructions.