The surprising discovery was made by medical staff in Dundee after the patient, now aged 42, complained of swelling over her eye.
The lens was found lodged in a cyst which had mysteriously flared up after more than a quarter of a century.
The woman had been struck in the eye by a shuttlecock when she was 14, and it had been assumed the lens had been knocked out by the impact.
The case was reported in the medical journal The BMJ.
Researchers at Ninewells hospital carried out an MRI scan after the woman was referred to the Department of Ophthalmology by her GP.
The patient presented with left upper eyelid swelling and ptosis (a droopy eyelid), according to doctors Sirjhun Patel, Lai-Ling Tan, and Helen Murgatroyd.
Images revealed an ovoid-shaped cyst about 8mm long but there was no evidence of anything inside it.
When surgeons removed the lump, the cyst ruptured revealing the lens.
Dr Patel and colleagues wrote: “On further questioning, the patient’s mother recalled that the patient had a history of blunt trauma to the upper left eyelid as a child.
“The patient was hit in the left eye with a shuttlecock while playing badminton at the age of 14.
“The patient was wearing an RGP (Rigid Gas Permeable) contact lens at the time, which was never found.
“It was assumed that the contact lens dislodged out of the eye and was lost.”