Russian opposition leader Aleksei Navalny has been briefly hospitalized after being hit in the face by green dye, the second time he has been targeted with a green liquid in the past five weeks.
Navalny on April 27 said his cornea was damaged when he was hit by the green dye outside the Moscow headquarters of the Anticorruption Fund, which he established.
It was not clear who carried out the attack.
"Shrek 2: now one-eyed," Navalny wrote on his blog alongside a picture showing his face spattered and one eye half-shut. He also said that "my eye burns from the fire of hell and I cannot open it."
Navalny is seeking to run for president in March 2018 -- a direct challenge to President Vladimir Putin, who is widely expected to seek a new six-year term.
On March 20, Navalny was doused with green antiseptic while opening a campaign office in the Siberian city of Barnaul.
Russian authorities say Navalny will be barred from the ballot if a conviction on financial-crimes charges is upheld on appeal.
He denies wrongdoing and has vowed to press on with his campaign.
The attack comes the same day as police searched a Moscow office of Open Russia -- a nongovernmental organization that has called for antigovernment street protests on April 29.