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The ancients were aware of the magnify property of crystal and did some research on it. Now let us say that some ancient genius had worked out how to develop decent lens. There would be a big market in reading glasses which could push startups in this industry.
In the space of about 400 years afterwards, telescopes were invented which was widely used by the military and the navy. The microscope was developed soon after that. Then soon the semaphore line was established which allowed messages to be sent in hours which used to take despatch riders on horseback days to get there.
Now, what if such technology had been available to the ancient Romans 2000 years ago. Having glasses would greatly increase their economic productivity. It would give them a substantial military advantage over their barbarian enemies on the field. It would be beneficial for their ships. It would probably provide them with a germ theory which might have a significant effect on their sanitation. It would revolutionise their knowledge of the heavens which would have a considerable impact on religion. It would also give them much faster communications in their empire.