This patient presented complaining of pain when he woke up one morning. He has also had pain in the eye a couple afternoons. On examination he has this small irregularity just below the pupil on the cornea. This irregularity causes adhesion between the lid and the cornea during sleep and then when waking up the outer protective cells of the cornea come off with the lid, exposing the unprotected layers beneath.
Treatment is usually artificial tears to start with. If that is not enough, then a special ointment at bedtime helps. If that doesn’t help, then surgery to flatten the area of the cornea is indicated.
How does the irregularity start to begin with? It can occur from a genetic disorder that causes an irregular corneal surface, or from scarring from a previous injury, or a focal scar from a previous herpes simplex virus infection.