Gardaí at Watercourse Street in Cork are appealing for witnesses following the assault, which occurred at Rings Bar on Church Street, Cork City.
The incident happened at approximately 10pm on Sunday, April 16 2017.
The man was rushed to Cork University Sanatorium.
Independent.ie understands that the man has lost sight in one of his eyes as a result of his maltreatments.
Gardaí are keen to speak to anyone who can help in their ongoing discovery procedure and would like to speak to anyone who was in the pub that night.
Anyone with low-down can contact Watercourse Rd Garda Station on 021-4558260, the Garda Intimate Line 1 800 666 111 or any Garda Station.