Sir Elton John shared a concerning health update about his vision in a recent interview to promote his new documentary, Disney+'s Elton John: Never Too Late, which is set to premiere next month.In an interview, John discussed his latest collaboration with Brandi Carlile a song titled "Never Too Late," which inspired the name of his documentary and shared heartbreaking details about losing his eyesight in recent months."I unfortunately lost my eyesight in my right eye in July, because I had an infection in the south of France. It's been four months now since I haven't been able to see," John told Good Morning America's Robin Roberts when asked about whether he'd make a new album. "My left eye is not the greatest. There's hope and encouragement that it will be OK, but I'm kind of stuck in the moment."The music legend continued, "I can do something like this [an interview] but going into the studio and recording, I don't know. I can't see a lyric, for a start. We're taking an initiative to try and get it better. But, at the moment, that's really what we're concentrating on. It's never fortunate for anything like this to happen, and it kind of floored me. I can't see anything. I can't read anything. I can't watch anything."John also explained how his latest collaboration with Carlile came about."She [Carlile] wrote this song called 'Never Too Late,' and everything in the lyric encompasses what I've been through," he explained. "She said, 'You're an Iron Man, baby.' And I am a bit of an Iron Man. I've been through so much and I've come out the other side."GMA host Roberts asked John if the lyrics to "I'm Still Standing" are resonating with John even more at this time in his career.The singer replied, "I'm so lucky. I'm the luckiest man in the world. I'm so proud of the documentary. I'm proud of my sons. I'm proud of my attitude towards myself and what's going on.""I'm just very lucky and I'm very grateful," John concluded.Elton John: Never Too Late premieres Friday, December 13 on Disney+.