A 14-year-old British girl playing badminton was hit in the eye with the birdie, and lost her contact lens.
Twenty-eight years later, doctors found it, embedded in a cyst in her left eyelid.
Now 42, the woman had visited an ophthalmologist because her eyelid was swollen and drooping, and she could feel something solid under the skin, according to the journal BMJ Case Reports.
An MRI revealed a tiny cyst just above her eye, which doctors removed.
The growth split open afterward, revealing the long-lost contact lens.
The woman, who was not identified in the study, couldn't immediately explain the strange discovery.
Then her mother recalled the badminton accident and the lost contact lens. After that injury, the girl stopped wearing hard lenses.
Doctors said the hard lens drifted into the woman's upper eyelid and remained there.
The physicians said they couldn't explain why the foreign body went unnoticed until her eyelid began to sag.