ICD-10 Code H40.1 – Open-angle glaucoma (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H40.1 – Open-angle glaucoma
What it is
H40.1 identifies open-angle glaucoma, a chronic eye disease in which optic nerve damage is associated with impaired aqueous humor outflow. It is commonly documented as primary open-angle glaucoma unless another cause is specified.
Clinical signs
Clinical features may include gradual peripheral vision loss, optic disc cupping, and elevated intraocular pressure, though pressure can be normal in some cases. Clinical features vary; refer to documentation.
When to use this code
Use H40.1 when the provider documents open-angle glaucoma without a more specific subtype or laterality that requires a more detailed code. Apply it for confirmed glaucoma diagnoses in outpatient, inpatient, or problem-list documentation. If the record names a secondary cause or different glaucoma type, code that instead.
Do not use for
Do not use H40.1 for angle-closure, congenital, traumatic, or drug-induced glaucoma. If documentation only says “glaucoma” or is unclear, check documentation before coding.
Coding tip
Review the chart for laterality, stage, and cause, because a more specific glaucoma code may be available.