Pupil abnormalities refer to irregularities in the size, shape, or reaction of the pupils in the eyes. Normal pupils are typically round and equal in size, responding to light and focusing. Abnormalities can indicate various medical conditions, such as Horner's syndrome, Adie's pupil, or Marcus Gunn pupil, which may affect vision or signal underlying health issues. Common causes of pupil abnormalities include neurological disorders, eye injuries, or the effects of certain medications. For instance, opioids can cause constricted pupils, while anticholinergic drugs may lead to dilation. Proper assessment by a healthcare professional is essential for diagnosis and treatment.