03/12/2020
Did you know that back in the 13th century, Italian glassblowers discovered that they could create crude glass lenses of different thicknesses that would add or subtract from the eye’s focusing power to compensate for these vision problems?
As they came to understand the physics behind flawed vision, three types of handblown lenses evolved:
Concave lenses: Thick at the perimeter and thin at the center, the concave shape moved the eye’s focus back toward the retina screen to correct nearsightedness (myopia).
Convex lenses: Like a magnifying glass, these lenses are thickest at the center, moving the eye’s focus forward from behind the retina to correct farsightedness (hyperopia).
Cylindrical lenses: The thicker/thinner portions of these lenses are asymmetrical, designed to correct astigmatisms.
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