Adie's Pupil is a condition characterized by an abnormal dilation of one pupil, which reacts poorly to light but may respond to accommodation. This condition is often associated with damage to the autonomic nervous system, particularly affecting the ciliary ganglion. The affected pupil is typically larger than the other and may appear sluggish when exposed to bright light. Adie's Pupil is usually benign and can occur in isolation or as part of Adie's syndrome, which may include other symptoms like decreased deep tendon reflexes.