ICD-10 Code H21.31 – Exudative cysts of iris or anterior chamber (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.31 – Exudative cysts of iris or anterior chamber
What it is
H21.31 identifies exudative cysts involving the iris or anterior chamber. Use it when documentation describes a cystic lesion related to exudation in this part of the eye.
Clinical signs
Clinical features vary; refer to documentation. You may see an iris or anterior chamber cyst noted on exam, imaging, or ophthalmology assessment, sometimes with visible anterior segment abnormality.
When to use this code
Use this code when the provider documents an exudative cyst of the iris or anterior chamber as the diagnosis. It is appropriate for confirmed ocular cysts in the anterior segment, including follow-up visits when the condition remains active. If the record only says “eye cyst,” check documentation for location and type.
Do not use for
Do not use this code for cysts in other eye structures, such as the eyelid, conjunctiva, or choroid. Check documentation if the note describes a non-exudative or unspecified cyst.
Coding tip
Confirm both the anatomic site and the exudative nature before assigning H21.31.