A missing contacts lens isn’t something you should turn a blind eye toward.

Case in point: A 42-year-old woman in Great Britain who lost a lens when she was a teen, only to have doctors discover it embedded in her eye 28 years later.

According to the medical journal BMJ Case Reports, the patient went to the doctor after she discovered a pea-sized lump below her left eyebrow.

The cyst was visible on an MRI and cause the woman’s left eyelid to droop, according to CNN. 

When doctors went in to remove the cyst, they discovered a rigid contact lens that somehow migrated into the eyelid, according to USA Today.

At first, the woman couldn’t recall how the contact lens got stuck in her peepers. Then her mom remembered the patient losing a lens during a badminton game when the patient was just 14.

Since the woman had no symptoms, she figured the lens had simply fallen out and gone missing.

“The patient never wore [rigid gas-permeable] lenses following this incident. We can infer that the RGP lens migrated into the patient’s left upper eyelid at the time of trauma and had been in situ for the last 28 years,” the authors said in their report.

Once the cyst and the lens were removed from the woman’s eyes, her peepers went back to normal.

This isn’t the only bizarre eye injury that’s hard to stomach.

In late 2016, a 67-year-old British woman went in for cataracts surgery only to discover the “blueish mass” in one of her eyes was actually 27 contact lenses.

If something similar happens to you and you don’t have nearly three decades to wait for removal, Health.com suggests flipping your upper eyelid to see if it’s hiding underneath and using saline drops to flush it out.

If that doesn’t work, see your eye doctor.