Anna Nicole Smith's daughter Dannielynn suffers from "strabismus, which is a turning in of one of her eyes," the baby's father, Larry Birkhead, told "Entertainment Tonight."
"I've been taking her to the doctors and ... [mom] Anna [Nicole Smith] had taken Dannielynn to the doctor [in the Bahamas] to see about it when she was just a few months old," he told the program.
Birkhead said the child wears an eye patch to help treat the condition, which is common in about 5 percent of children and cannot be outgrown.
"At first she was really open to it and it didn't really bother her," he said. "Now, she's gotten a little smart because she can pull it off, so it's a little bit harder for me to patch her."
She also takes medicated eyedrops. But if neither works, he says she may have to have surgery.
"I'm going to do everything to make sure that it's corrected," he said, "but having lost Anna and [her son] Daniel and my dad — my dad just came out of a simple surgery and he died — it's just tough for me to think about surgeries with [Dannielynn]."
He said he is not sure how she developed the eye condition.
"All of the opinions that I had [from doctors], every one of them said that it's very, very unlikely, because no one knows one-hundred percent what causes [strabismus]," said Birkhead.
"But I point-blank ask every single doctor, 'Could any medications that Anna was on have caused this?' and they said that it's more likely that a genetic reason could have caused it."