@DusselDuck Essilor is the largest eyewear manufacturer, yes. But in terms of lens processing, Hoya is a number of its own Then comes Rodenstock and then Essilor.
@Der_Dividenden_Monteur I don't know what sources you use, but everywhere I look, Essilor is the leader (in lenses, not frames) Addition (according to Statica.com, by market share): 1st Essilor / Varilux 12% 2. Hoya 10% 3. Transistions 9%
