ICD-10 Code H40.031 – Anatomical narrow angle, right eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H40.031 – Anatomical narrow angle, right eye
What it is
This code identifies a narrow anterior chamber angle in the right eye due to anatomy. It signals a structural risk for impaired aqueous outflow and angle-closure glaucoma.
Clinical signs
Findings may include a shallow anterior chamber, narrow or crowded iridocorneal angle on exam, and elevated concern for angle closure. Clinical features vary; refer to documentation.
When to use this code
Use H40.031 when the provider documents anatomical narrow angle specifically in the right eye. It is appropriate for screening, follow-up, or evaluation notes that confirm the right-sided finding. Code the documented laterality exactly as recorded.
Do not use for
Do not use this code for primary angle-closure glaucoma, glaucoma suspect without documented narrow angle, or unspecified laterality. Check documentation if the record only mentions narrow angles generally.
Coding tip
Confirm laterality and whether the note describes anatomy alone versus glaucoma or suspected glaucoma before assigning H40.031.