Characterizing product performance photography as visual imaging that influences designer thinking in user-centred rehabilitation product development

User-centred design in rehabilitation often struggles to translate patient experiences into meaningful design insights. This study addresses that gap by characterizing Product Performance Photography (PPP) as a visual imaging method that influences designer thinking in rehabilitation product development. Grounded in Design Thinking theory, the research explores how visual data can enhance empathy, cognition and ideation among designers engaged in rethinking assistive hand splints for stroke patients. A qualitative multi-method approach was employed, combining three interrelated phases: (i) content analysis of scholarly sources to identify key dimensions of patient experience (PEX); (ii) Product Performance Photography to visually capture real-life interactions between patients and their hand splints; and (iii) Verbal Protocol Analysis (VPA) with designers to examine how these visual cues shaped their reflective reasoning and design decisions. Data were analysed thematically using MAXQDA to reveal recurring patterns of empathy, perception and design response. Findings demonstrate that PPP functions through referential, communicative and aesthetic dimensions, enabling designers to understand patient challenges such as discomfort, stiffness and emotional frustration. The visual data fostered empathetic reflection and inspired adaptive redesign ideas, including softer materials, adjustable wrist joints and easier fastening mechanisms. The study contributes a visual design framework that positions PPP as a mediating artefact within the early stages of Design Thinking (Empathise - Define Ideate). By foregrounding authentic visual data, PPP transforms photography from passive documentation into an active cognitive tool that drives empathy-based innovation. The research extends beyond the technical domain of product design, highlighting the broader relevance of visual inquiry for healthcare innovation, interdisciplinary design and inclusive creative practice.