As someone who knows very little about medicine, this is awesome. Seems like the entire concept could be extrapolated to other types of diseases that can be diagnosed using image processing.
Its funny how the iPhone often gets used for its sensors/functionalities for far flung use cases. I wonder if an android phone would be capable of this.
The test would need to be validated against a single SKU of phone, guaranteed to have the same camera module across all units. That's a big advantage of using the iPhone for hardware applications - the number of configs is very small.