Global proliferation of mobile technology presents huge opportunities for healthcare, specifically regards improving operational efficiency, lowering costs, extending health systems' reach and improving adherence and acceptance. Foremost of reasons cited as prohibiting advancement of mHealth technologies from pilot to widespread adoption is paucity of data concerning the full impact on the health system's workflow.;The aim of this thesis is to investigate whether workflow modelling techniques, established in other fields, might be applied to the field of mHealth to address the lack of knowledge concerning its full health-system impact. Thus, it seeks to provide information that will help reduce the number of mHealth designs that fail to produce results in clinical pilots that lead to adoption at scale.;Data on the operation of proposed mHealth designs for use in community eye screening and retinopathy of prematurity screening were sourced from the scientific literature, technical datasheets and lab-based testing in the first instance and then pilot studies embedded in a community eye health study in Nakuru, Kenya. This included the design and prototyping of a novel smartphone-based ophthalmoscope appropriate for community settings in low-income countries.;The data acquired were analysed using standard statistical techniques. These analyses were then used to build stochastic timed coloured Petri-nets.;Classical statistical simulations based on these models generated data concerning the optimal design, workflow placement and usage of the mHealth devices. The data relating to retinopathy of prematurity screening specifically was used to design a tablet-computer operated, portable fundus camera for screening of preterm infants.;The results suggest that several mHealth design parameters have optimal values at odds with many of the piloted technologies that have failed to achieve adoption within the respective scenarios. It is recommended that further research, extending the techniques discussed and validating their effectiveness at producing designs appropriate for scale, be undertaken.