ICD-10 Code H21.543 – Posterior synechiae (iris), bilateral (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.543 – Posterior synechiae (iris), bilateral
What it is
H21.543 identifies posterior synechiae in both eyes, meaning the iris is abnormally attached to the lens. Use this code when documentation clearly states bilateral involvement.
Clinical signs
Findings may include irregular pupil shape, poor pupillary movement, or evidence of iris adhesion on eye examination. Clinical features vary; refer to documentation.
When to use this code
Use H21.543 when the provider documents posterior synechiae affecting both irides, whether as a primary finding or as part of another eye condition. Code it from ophthalmology notes, exam reports, or consults that specify bilateral posterior synechiae. Check documentation if laterality is unclear.
Do not use for
Do not use this code for unilateral posterior synechiae or for other iris adhesions without posterior involvement. If the record does not confirm bilateral disease, do not assume it.
Coding tip
Verify laterality in the exam note before assigning H21.543.