Table 1.

Usability dimensions.

Usability dimension		No. of HCPsa	Rationale given by HCPs	Benefits relating to usability dimension	HCP quotes
Efficiency
	Time	8	Simple and easy to use, with less manual record keeping.	Ability to see more patients, early diagnosis, and treatment.	“ ...it will be more effective in that we will be able to get to see more patients with eye problems and in that case I will be able to solve them early enough and our patients will not have to go blind...”
	Multitasking	6	Requires less equipment to navigate and manpower to conduct examinations.	Saves human resources.	“ ...you can multi task it by doing all the examination at the same place without moving just by the touch of the application, so it will make it better.”
	Portability and convenience	7	Easier to carry around compared with traditional equipment.	Increase access and coverage in remote areas.	“ ...it’s portable and one can be able to access rural areas where infrastructure is poor so in terms of accessing those places you will be able to get people who could not think of getting help...”
	Cost	6	Cheaper equipment (10,000-40,000 KESacompared with more than 1,000,000 KES for traditional equipment), transport, and negligible software costs and replacement costs.	Economic gains for patients and service provisions.	“ ...the cost of one Portable eye kit does like very many examination procedures compared to the machines so it makes it cheaper, two the cost of transport is cut down because I’ll be able to visit the client at his/her own convenience...”
Effectiveness		6	Accurate, equal, or better than traditional equipment.	Ability to provide better analysis of findings, compared with the substitute.	“ The phone is automatically accurate than the traditional type of equipment. PEEK is more advanced than the traditional equipment gives you the exact figures and images. It is very accurate. Excellent in fact”
Learnability		8	Clear instructions; though useful, no expertise required.	Usable by less qualified HCPs with limited smartphone knowledge.	“ ...anybody as long as you have something in between your ears that is a brain then you can actually work. Because everything is just written and where it is not written you can actually see it everything is self-explanatory with algorithms.”
Flexibility and operability		8	Quickly modifiable based on user feedback and robust technology.	User-friendly, easy to maintain, and meets different needs.	“ ...it is still open ended it is not closed so it is it is able to accommodate, new things and new ideas and new situations that may vary from one region to another from one country to another so it is adaptable.”

^aHCP: health care provider; KES: Kenyan shilling.