Quan Tech Quest Ltd. Advances in Medical Informatics 2819-8298 1 2025 05 14 Usability Evaluation of the Doctor Saina Online Consultation Application Using the Think-Aloud Method 5 5 eng Faezeh Raje Department of Health Information Technology, Varastegan Institute for Medical Sciences, Mashhad, Iran Fateme Moghbeli Statistical Data Analyst- Researcher and Assessment Services, York Region District Board (YRDSB), Ontario, Canada Zahra Sangsefidi Department of Health Information Technology, Varastegan Institute for Medical Sciences, Mashhad, Iran Hamed Maktabdar Roshkhar Sadjad University of Technology, Mashhad, Iran Mohammad Reza Mazaheri Habibi Department of Health Information Technology, Varastegan Institute for Medical Sciences, Mashhad, Iran 0000-0001-8096-2530 2025 04 22 2025 05 10 Introduction: The rapid advancement of technology and economic growth has created both opportunities and challenges in healthcare accessibility. The unequal distribution of medical resources, which disproportionately favors economically developed regions, has led to a decline in the quality and efficiency of healthcare services in rural and underdeveloped areas, highlighting the urgent need for innovative solutions. Telemedicine effectively overcoming geographical barriers and improving access to medical care. However, usability issues in some of these applications present significant challenges, potentially compromising service quality and user experience. This study aimed to evaluate the usability of the Doctor Saina application, identifying key factors that influence its effectiveness, user satisfaction, and overall success. Material and Methods: In this study, digital health application Doctor Saina which facilitate online medical consultations, making healthcare services more accessible, was examined. A laboratory-based usability evaluation was conducted using a predefined scenario-driven approach and the think-aloud method with 15 participants. The identified usability issues were categorized using the Van den Haak classification framework, and their severity was assessed based on Nielsen’s heuristic evaluation model. Results:  The average duration of the usability evaluation per participant was 22.08 minutes. During the evaluation process, 23 issues were identified by the users, 5 of which had a severity greater than 2. The most frequent usability issues identified by users were in the Comprehensiveness category (43.5%). During the evaluation process, 9% of the issues were resolved by users without facilitator intervention. Conclusion: Among the identified usability challenges, layout and comprehensiveness were reported as the most significant barriers affecting user experience. Addressing these issues is crucial for enhancing the overall usability, accessibility, and effectiveness of the Doctor Saina application.