2026 ICD-10-CM Diagnosis Code H40.1231Low-tension glaucoma, bilateral, mild stage

ICD-10-CM Codes›H00–H59›H40-H42›H40

ICD-10-CM H40.1231
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H40.1231 is a billable ICD-10-CM diagnosis code for low-tension glaucoma, bilateral, mild stage. The 7th character 1 reports mild stage glaucoma. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Glaucoma.

Code Identity

ICD-10-CM Code
H40.1231
Billable Status
Yes — Valid for Submission
Code Describes
Low-tension glaucoma, bilateral, mild stage
Short Description
Low-tension glaucoma, bilateral, mild stage
Same as the full description in the CMS dataset.
Parent Code
H40.123
Low-tension glaucoma, bilateral

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH40-H42Glaucoma
CategoryH40Glaucoma
This CodeH40.1231Low-tension glaucoma, bilateral, mild stage

Code EditsBilling

Medicare Code Editor checks that affect claim validity for H40.1231.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Quality Payment Program MeasuresBilling

Medicare quality measures that can apply when H40.1231 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 No · 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 H40.1231 to ICD-9-CMHistory

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

ICD-9-CM
365.12 Low tension 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
365.71 Mild 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 HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About H40.1231Overview

Is H40.1231 (Low-tension glaucoma, bilateral) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report low-tension glaucoma, bilateral, mild stage on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character 1 in H40.1231 mean?

The final character 1 reports mild stage glaucoma, in this case involving the low-tension glaucoma.

Can H40.1231 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because low-tension glaucoma, bilateral, mild stage describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

What is the ICD-9 equivalent of H40.1231?

Under the General Equivalence Mappings, low-tension glaucoma, bilateral, mild stage converts to ICD-9-CM 365.12 (low tension glaucoma) and 365.71 (mild 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.