Mydriasis

This code describes the abnormal, persistent dilation of the pupil, which can be unilateral or bilateral. Mydriasis results from an imbalance in the autonomic nervous system's control over the iris muscles, leading to an enlarged pupil that does not constrict normally in response to light.

Use this code when documentation specifies mydriasis as a presenting symptom or a diagnosed condition. This may include cases of drug-induced mydriasis, traumatic mydriasis, or mydriasis due to neurological conditions. Supporting documentation should clearly state the presence of pupillary dilation.

• Do not confuse with anisocoria (unequal pupil size) unless mydriasis is the specific cause of the inequality.
• Code any underlying cause of the mydriasis, such as a neurological disorder or drug toxicity, as a primary diagnosis if applicable.
• Specify laterality (right, left, or bilateral) if documented, using the appropriate subcategory.