Startup Idea: Eye Prescription Identification Application

Startup idea to develop an app that identifies eye prescriptions. Users read letters shown on the screen and their responses are analyzed by the software to determine an accurate eye prescription.

I've always thought of an idea of creating an app that could correctly identify eye prescriptions. You hold your smartphone and it shows letters and then you'd use the microphone to say the letters if you can see it. It then creates a prescription for you in diopters for you to use.

I'd try to create software like this but don't have the programming knowledge.