Graduate Trying to source Photochromic lenses based on laboratory data

[Vakho]

TL;DR

Photochromic lenses

Hello,

I have a photochromic lenses that I analyzed in a laboratory using a spectrometer. I sent the obtained data to various manufacturers in China, but for some reason, they are unable to produce an exact match. Instead, they sent me a similar material.

What could be the reason for this, and how can I solve this issue?

 

[Tom.G]

Try German and/or American manufacturers.