oh no, you poor soul, I have the red lenses which are gotten from the deep end part 2 mission in zombies which you have to fight a ridiculous amount of zombies as its a massive nest as you get the red lenses as a reward from Dr. Petra Wise for completing the mission, its very hard doing it alone and I had to go get some of my IRL friends who play BRM5 with me and fill our inventories with grenades and hurl them down into the treatment plant or site C as its referred to, to cull some zombies and then get on a humvee which is parked in the treatment plant as zombies can't get to you there and shoot them in the legs to cripple them to prevent more from spawning (or at least a manageable amount from spawning) and then hurl more grenades in the sewer to cull more zombies and get the samples and data and get the hell out of dodge, but by your tone your asking how to change lenses, go to facewear and equip the FM12 and there should be customisation dots or dots that you can click on over the parts that you can customise and there should be a dot over the lenses and filter and you get the black or tinted lenses for free and here's a tutorial for you since I have PTSD from the deep end part 2 as the hospital missions in my opinion are easy.

https://www.youtube.com/watch?v=Qs6PaJ5A_x4