ICD-10 Code H21.21 – Degeneration of chamber angle (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.21 – Degeneration of chamber angle
What it is
H21.21 identifies degeneration of the chamber angle, the drainage area where aqueous humor leaves the eye. Use it when documentation specifically describes degenerative change in the anterior chamber angle.
Clinical signs
Clinical features vary; refer to documentation. Findings may include abnormal angle appearance on gonioscopy or other eye examination that supports degenerative change rather than acute inflammation or injury.
When to use this code
Use this code when the ophthalmology note states degeneration of the chamber angle, angle degeneration, or a similar documented diagnosis. It is appropriate for outpatient, consult, or follow-up encounters when the condition is the reason for evaluation or affects care.
Do not use for
Do not use it for glaucoma, angle-closure disease, or traumatic angle injury unless the provider documents degeneration of the chamber angle. Check documentation if the note only mentions abnormal intraocular pressure or a nonspecific anterior segment finding.
Coding tip
Code only when the provider names chamber-angle degeneration; otherwise, query or check documentation for a more specific eye diagnosis.