PMCH superintendent Dr Lakhinder Prasad told HT on Monday that a team of eye specialists had examined Vikas Yadav, the victim, recently.
“The acid has badly burnt the cornea and it is irreparable,” he said, adding that the injuries in his two hands were healing fast.
Miscreants had attacked Yadav, a resident of Vanbhaur village in the Bithan area (Samastipur district), last Thursday. The village is 100km northeast of state capital Patna.
He was taken to a hospital in Samastipur before being referred to PMCH.
Police said Yadav had a criminal past and was overpowered by a rival group after a failed bid to kill one of the gang members.
Police have made just one arrest in connection with the case so far. Five other accused are on the run.
Rosera deputy superintendent of police GM Kumar said the process to confiscate the property of those absconding had been initiated.