Separate surface design from refractive index, coatings and processing scope. Compare spherical and aspheric lenses using identifiable designs and consistent sample records.
Compare 1.61, 1.67 and 1.74 lenses by material identity, finished geometry and order scope. Use a consistent comparison record before approving an index change.
Understand hard coating, anti-reflective treatment and hydrophobic finishes, then compare coating packages with a practical buyer specification record.
