Lens index: what 1.50, 1.60 and 1.67 mean
Higher index can change thickness, but it is only one part of choosing a lens.
THE CLEAR VISION GUIDE
Lens materials
Look beyond the index number.
Why frame size changes lens thickness
Your prescription, frame shape and fitting measurements work together.
Lens materials: more than thinness
Discuss weight, optical properties and impact needs as separate requirements.
Polycarbonate and Trivex: when impact matters
Compare a lens material with the requirements of the whole pair of glasses, especially for active use.
Abbe value: why some lenses show colour fringes
Understand dispersion without turning one material number into a universal quality score.
Aspheric lenses: design, appearance and fit
Learn what a flatter lens design can change and which questions still need an individual answer.