ICD-10 Code H21.302 – Idiopathic cysts of iris, ciliary body or anterior chamber, left eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.302 – Idiopathic cysts of iris, ciliary body or anterior chamber, left eye
What it is
This code identifies an idiopathic cyst in the left eye involving the iris, ciliary body, or anterior chamber. “Idiopathic” means the cause is not known.
Clinical signs
Clinical features vary; refer to documentation. These cysts may be found on eye examination as a visible fluid-filled lesion in the anterior segment, with or without visual symptoms.
When to use this code
Use H21.302 when the provider documents an idiopathic cyst affecting the left iris, ciliary body, or anterior chamber. Apply it when the record specifies the left eye and does not identify a secondary cause.
It may also fit follow-up visits for a known idiopathic cyst if the diagnosis remains active. Check documentation if the cyst is described as congenital, traumatic, inflammatory, or otherwise secondary.
Do not use for
Do not use this code for cysts with a known cause, such as trauma, inflammation, or surgery-related findings. Do not use it if the documentation does not specify the left eye.
Coding tip
Verify laterality and the word “idiopathic” in the ophthalmology note before assigning H21.302.