In patients with extremely poor vision, typically advanced glaucoma, spurious images are generated by the visual cortex (brain), which can be distressing for the patient.  One such patient, I recently saw, described black and green vertical ribbons with snake-like heads moving against a honeycomb pink and grey backdrop.  Each patient’s experience will be unique, however.  Unfortunately, there is no specific treatment, but most patients are reassured that this experience has been described by other patients in similar circumstances.