Tottenham defender Jan Vertonghen accidentally gouged Firmino's eye as the pair tussled for the ball at Wembley, meaning that the Brazilian was briefly taken to hospital before being returned home.
However, the 26-year-old was well enough by Tuesday to make the bench for Liverpool's game against PSG, and score an injury time winner for the Reds.
Footage emerged on the Instagram account of Liverpool defender Alberto Moreno on Wednesday of Firmino trying on a pair of glasses that look to be specifically designed to protect his eye. He then was captured wearing them in training as Liverpool warmed down after their Champions League group stage win.
Firmino's recovery was unexpectedly fast according to manager Jurgen Klopp.
"There was no chance yesterday (Monday). Absolutely no chance the day before (Sunday). But he came (on Tuesday), he came in and said "I'm fine. I can open my eye again." It was good!" said Klopp of Firmino's chances of playing against PSG.
Roberto Firmino in training today. Should replace what he's wearing with the thug life glasses