My culture had access to quality materials (lead oxide) for glass creation, high-enough grit materials for polishing glass, a basic understanding of magnification and mirrors, and about Kepler-level of lens-knowledge in 50 BC, with all other technologies being about the same as the Roman Empire for 50 BC. Assuming the same historical Earth conditions from 50 BC to 1000 AD, what technologies would have advanced faster than they did in our history?
A few I can think of offhand: Astronomy would be much more advanced, and thus sea travel might have advanced at a more rapid pace. Corrective lenses might have improved productivity and quality of life. Microscopes might have advanced germ knowledge at a much earlier age, and thus improved medicine and sanitation. What else am I not thinking of?