ICD-10 Code H40.033 – Anatomical narrow angle, bilateral (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H40.033 – Anatomical narrow angle, bilateral
What it is
This code identifies a bilateral anatomic narrowing of the anterior chamber angle in the eye. It indicates a structural risk factor for angle-closure glaucoma, not necessarily active glaucoma.
Clinical signs
Findings may include shallow anterior chambers and narrow angles on gonioscopy. Clinical features vary; refer to documentation.
When to use this code
Use H40.033 when the provider documents anatomical narrow angles in both eyes, with or without symptoms. It is appropriate when the record supports a bilateral anatomic finding rather than established glaucoma or an acute angle-closure event.
Choose this code when the note clearly states narrow angles on exam, imaging, or specialist assessment. If the documentation is unclear, check documentation before coding.
Do not use for
Do not use this code for unilateral narrow angle, angle-closure glaucoma, or other glaucoma types. Do not use it when the chart only says “glaucoma suspect” without bilateral anatomical narrow-angle documentation.
Coding tip
Confirm laterality and distinguish anatomic narrow angle from glaucoma before assigning H40.033.