ICD-10 Code H21.329 – Implantation cysts of iris, ciliary body or anterior chamber, unspecified eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.329 – Implantation cysts of iris, ciliary body or anterior chamber, unspecified eye
What it is
This code identifies an implantation cyst involving the iris, ciliary body, or anterior chamber, when the eye is not specified. It refers to a cystic lesion formed by implanted epithelial tissue inside the eye.
Clinical signs
Findings may include a visible cystic mass in the anterior segment, iris distortion, or anterior chamber involvement. Clinical features vary; refer to documentation.
When to use this code
Use H21.329 when the provider documents an implantation cyst in the iris, ciliary body, or anterior chamber and does not name the eye. It is appropriate for postoperative or traumatic implantation cysts when laterality is not recorded. Check documentation if the record describes a different anterior segment lesion.
Do not use for
Do not use this code for cysts in a specified eye when laterality is documented. Do not assign it for other iris or anterior chamber disorders, or for non-implantation cysts.
Coding tip
Confirm both the anatomic site and whether the eye is unspecified before coding.