FL-41 is a generic tint that has been proven to help with conditions associated with light sensitivity.  We are the original retailer of SpectraShield tinted lenses online.  Our proprietary Spectrashield tint looks distinctly different than the generic  FL-41 version.  Our blend has been fine-tuned over 20 years.

SpectraShield successfully blocks the distressing portion of the light spectrum, which bothers light sensitive people and causes cumulative eye damage over a lifetime.  All of our lenses also block UVA and UVB light.