ICD-10 Code H21.30 – Idiopathic cysts of iris, ciliary body or anterior chamber (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.30 – Idiopathic cysts of iris, ciliary body or anterior chamber
What it is
This code identifies a cyst in the iris, ciliary body, or anterior chamber when the cause is not known. Use it for a documented idiopathic cyst, not for a mass with a clear underlying cause.
Clinical signs
Findings may include a visible cyst on eye examination, sometimes with no symptoms. Clinical features vary; refer to documentation.
When to use this code
Use H21.30 when the provider documents an idiopathic cyst affecting the iris, ciliary body, or anterior chamber. It is appropriate when the record states the lesion is benign-appearing and no specific cause is identified. Check documentation if the note only says “eye cyst” without location.
Do not use for
Do not use this code for cysts with a documented cause, such as trauma or surgery. Do not assign it when the record describes a different anterior segment lesion or the location is not specified.
Coding tip
Confirm both the anatomic site and the idiopathic nature of the cyst before coding H21.30.