I had a patient referred to me from a corneal specialist. The patient has a history of a corneal transplant in the right eye and some corneal dystrophy in the left eye. The transplant looked great. There was a significant difference in prescription between the two eyes. She was already wearing rigid gas permeable lenses. They worked well. The patient needed a back-up pair of glasses. It's fortunate the patient is able to wear glasses. Sometimes when there is a significant difference in prescription between the two eyes, the patient can't function well with glasses. This is due to a difference in image size between the two eyes generated by the glasses. This generally does not occur with contact lenses. This is a situation when contact lenses are a lot better solution than glasses.