Lewis Hamilton said driving with one eye closed for part of the Monaco Grand Prix was "virtually impossible" after dirt got underneath his visor.
The Mercedes Formula 1 driver was heard complaining about the issue over team radio during the closing stages of the race.
The team invited him to pit for attention if required and made medical assistance available at the podium ceremony, but Hamilton said the problem eventually cleared itself.
He fell away from race-leading team-mate Nico Rosberg while struggling with his eye and was caught by Daniel Ricciardo's Red Bull, which finished just four tenths behind.
"I had quite a bit of wind coming in, I got close to Nico in one stage and I got some debris or dirt in my eye," Hamilton explained.
"I was driving with one eye which is virtually impossible to do.
"Through low speed corners I had to close eye which made it worse, but five laps to go it cleared up and I was able to stay ahead of Daniel."
RICCIARDO TRIED TO TAKE ADVANTAGE
Red Bull urged Ricciardo to try to take advantage of Hamilton's issue, and the Australian caught the Mercedes at a rate of 1.5 seconds per lap towards the flag before falling just short.
"I pushed and didn't need to save tyres, and we got close to one of the Mercedes in the end but it is quite hard to pass," said Ricciardo.
"I tried to put a bit of pressure on but third was the best we could do.
"I knew the team felt I had to catch him, I knew I would get on to him, and I was waiting to see what happened.
"I wasn't going to settle for third but if there was a clean move to be taken I would have taken it."