To the Editor.
—You recently published a case report1 in which the authors described a 22-year-old patient with multiple sclerosis who was said to be blind in the right eye from an optic neuritis but who still had sharp vision and full fields in the left eye. To the authors' surprise, the patient was found to have only a small, relative afferent pupillary defect in the right eye, and two days later even that defect had resolved. This observation led the authors into a fruitless discussion of retained pupillary responses in blind eyes. Faced with a similar situation, we would have challenged the patient's contention that she had no light perception in the right eye. In our clinic we rely heavily on the relative afferent pupillary defect and we would not have been so quick to abandon a valuable, trusted, and objective test.It seems likely that visual and