High-index materials bend light more efficiently than standard plastic, which can reduce lens thickness for stronger prescriptions. The visible difference depends on prescription power, lens shape, frame size, decentration, and the chosen material.
A smaller, well-centered frame can sometimes reduce edge thickness more effectively than selecting a very large frame with a higher index. Strong plus prescriptions have different thickness patterns from strong minus prescriptions, so a blanket thinnest claim is not useful.
Higher index does not automatically mean lighter or optically preferable for every prescription. Material density, lens dimensions, impact needs, and chromatic aberration all matter. Polycarbonate or Trivex may be considered where impact resistance is a priority.
Anti-reflective coating is commonly considered because higher-index surfaces can show more reflections. The final choice should be based on a reviewed prescription and frame combination, not only the material name.
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