ICD-10 Code H21.51 – Anterior synechiae (iris) (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.51 – Anterior synechiae (iris)
What it is
Anterior synechiae are adhesions between the iris and the cornea or trabecular meshwork. This code identifies documented iris adhesions that may affect aqueous outflow.
Clinical signs
Findings may include iris strands or broad adhesions seen on slit-lamp exam or gonioscopy. Clinical features vary; refer to documentation.
When to use this code
Use H21.51 when the record specifically documents anterior synechiae of the iris, whether incidental or associated with another eye condition. Apply it when the provider notes adhesions without a more specific underlying diagnosis being coded instead. Check documentation if the note only mentions angle closure or scarring.
Do not use for
Do not use this code for posterior synechiae, which involve the iris and lens. It is also incorrect for nonspecific glaucoma or other anterior segment abnormalities unless anterior synechiae are clearly documented.
Coding tip
Confirm the exact anatomic site in the ophthalmology note before assigning H21.51.