Question

what are the materials needed to make lens​

Answer 1

Except for the crown glass, these are all plastic materials. Less costly than 1.70-1.74 high-index lenses. Significantly more impact-resistant than CR-39 plastic and high-index plastic lenses (except polycarbonate and Trivex.....

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Answer 2

A GLASS SPHERE.

IS NEEDED WITH A CUTTING MATERIAL AND A HUMAN BEING OF COURSE.