STEPPER 135 SI 30128 F520 54
"The index number is a measurement of how efficiently a lens material bends light, which determines the lens's thickness and weight. A higher index number means the lens is thinner and lighter, making it the best choice for stronger prescriptions, while a lower index is suitable for weaker prescriptions and is more affordable."
TOMMY HILFIGER TH 1045 C3 GUNBK 53
"The index number is a measurement of how efficiently a lens material bends light, which determines the lens's thickness and weight. A higher index number means the lens is thinner and lighter, making it the best choice for stronger prescriptions, while a lower index is suitable for weaker prescriptions and is more affordable."