2026 ICD-10-CM Diagnosis Code H40.1123Primary open-angle glaucoma, left eye, severe stage

ICD-10-CM Codes›H00–H59›H40-H42›H40

ICD-10-CM H40.1123
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H40.1123 is a billable ICD-10-CM diagnosis code for primary open-angle glaucoma, left eye, severe stage. The 7th character 3 reports severe stage glaucoma. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 124 through 125. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Glaucoma.

Code Identity

ICD-10-CM Code
H40.1123
Billable Status
Yes — Valid for Submission
Code Describes
Primary open-angle glaucoma, left eye, severe stage
Short Description
Primary open-angle glaucoma, left eye, severe stage
Same as the full description in the CMS dataset.
Parent Code
H40.112
Primary open-angle glaucoma, left eye

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH40-H42Glaucoma
CategoryH40Glaucoma
This CodeH40.1123Primary open-angle glaucoma, left eye, severe stage

Quality Payment Program MeasuresBilling

Medicare quality measures that can apply when H40.1123 is part of the patient record.

Primary Open-Angle Glaucoma (POAG): Reduction of Intraocular Pressure (IOP) by 20% OR Documentation of a Plan of Care.

High Priority: YES

Measure Type: Outcome

Submission Methods: Claims, Registry

Description: Percentage of patients aged 18 years and older with a diagnosis of primary open-angle glaucoma (POAG) whose glaucoma treatment has not failed (the most recent IOP was reduced by at least 20% from the pre-intervention level) OR if the most recent IOP was not reduced by at least 20% from the pre-intervention level, a plan of care was documented within the 12 month performance period.

View Measure

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR EYE003
Glaucoma
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Glaucoma

Glaucoma is a group of diseases that can damage the optic nerve of one, or both, of your eyes. This can result in vision loss. There are different types of glaucoma, but the most common type is open-angle glaucoma. Other less common types include angle-closure glaucoma, and congenital glaucoma.

The full article covers:

  • What is glaucoma?
  • What causes glaucoma?
  • What are the symptoms of glaucoma?
  • How is glaucoma diagnosed?
  • What are the treatments for glaucoma?
  • Can glaucoma be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert H40.1123 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
365.11 Prim open angle glaucoma
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
365.73 Severe stage glaucoma
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

Code History & ChangesHistory

Replacement H40.1123 replaces the following previously assigned code(s):

  • H40.11X3 - Primary open-angle glaucoma, severe stage
FY 2018AddedAdded to the ICD-10-CM code setEffective October 1, 2017.
FY 2019–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About H40.1123Overview

Is H40.1123 (Primary open-angle glaucoma, left eye) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report primary open-angle glaucoma, left eye, severe stage on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character 3 in H40.1123 mean?

The final character 3 reports severe stage glaucoma, in this case involving the primary open-angle glaucoma.

What MS-DRG does H40.1123 group to?

When primary open-angle glaucoma, left eye, severe stage is the principal diagnosis on an inpatient stay, it groups to MS-DRG 124, 125, with relative weights from 0.7678 to 1.3231 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of H40.1123?

Under the General Equivalence Mappings, primary open-angle glaucoma, left eye, severe stage converts to ICD-9-CM 365.11 (prim open angle glaucoma) and 365.73 (severe stage glaucoma). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.