Boychuk returned Aug. 1 to play three games during the postseason, including two against the Tampa Bay Lightning in the Eastern Conference Final, though he said he knew "there was something going on" with the eye. Further medical tests resulted in Boychuk having to stop playing.
"There's some damage that has been diagnosed as irreversible, I guess," he said. "There could be something that can help me, but there's some that's not going to come back and that's what I've been told."
The injury in March was his second to the eye. Boychuk fractured an orbital bone when he was hit in the side of the head by a shot playing for the Boston Bruins against the Vancouver Canucks on Feb. 6, 2010, and said he began wearing a visor after that.
Boychuk scored 206 points (54 goals, 152 assists) in 725 NHL games with the Colorado Avalanche, Bruins and Islanders, and 30 points (13 goals, 17 assists) in 104 Stanley Cup Playoff games. He helped Boston win the Stanley Cup in 2011.
Boychuk, who has two seasons remaining on a seven-year contract he agreed to March 12, 2015, said he wasn't sure what he will do next.
"The injury's causing me to stop playing, so don't know if it's retiring or [long-term injured reserve]," Boychuk said. "I just know it's going to cause me to not play because it's basically not safe for me if I can't see things coming. For the future, I have no idea what to do. This has been two months of going to doctors, and I'm trying to think about what I can do after, but I'm not too sure yet. I want to be on [Long] Island, obviously. We built a house there. There were no plans on leaving. But I just don't know."