Optical Prescription Reading Theory Training

I run a small optician shop and need a concise, theory-based lesson that shows me exactly how to read and interpret prescription cards. My main priority is mastering the numbers, abbreviations, and parameters... (Budget: €2 - €6 EUR, Jobs: Content Development, Customer Service, Education & Tutoring, Optical Engineering, Optometry, Teaching/Lecturing, Training, Visual Merchandising)