ICD-10 Code H21.549 – Posterior synechiae (iris), unspecified eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.549 – Posterior synechiae (iris), unspecified eye
What it is
H21.549 identifies adhesions between the iris and the lens or ciliary body in an unspecified eye. Use it when the record states posterior synechiae of the iris but does not name right or left eye.
Clinical signs
Findings may include an irregular or fixed pupil, reduced pupil movement, and evidence of iris adhesion on eye examination. Clinical features vary; refer to documentation.
When to use this code
Use this code when the clinician documents posterior synechiae of the iris and laterality is not specified. It may also fit follow-up notes describing a known adhesion without new eye-side detail. Confirm the diagnosis is current, not merely historical.
Do not use for
Do not use this code if the chart specifies right or left eye; choose the laterality-specific code instead. Do not apply it to other iris disorders or to anterior synechiae.
Coding tip
If the note says only “posterior synechiae,” check the exam and assessment for eye laterality before defaulting to the unspecified code.