2026 ICD-10-CM Diagnosis Code H40.031Anatomical narrow angle, right eye

ICD-10-CM Codes›H00–H59›H40-H42›H40

ICD-10-CM H40.031
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H40.031 is a billable ICD-10-CM diagnosis code for anatomical narrow angle, right eye. 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
H40.031
Billable Status
Yes — Valid for Submission
Code Describes
Anatomical narrow angle, right eye
Short Description
Anatomical narrow angle, right eye
Same as the full description in the CMS dataset.
Parent Code
H40.03
Anatomical narrow angle

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH40-H42Glaucoma
CategoryH40Glaucoma
This CodeH40.031Anatomical narrow angle, right eye

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute angle closure due to anterior chamber angle anomaly
  • Acute angle closure due to intraocular neoplasm
  • Acute angle closure of right eye
  • Acute angle closure of right eye caused by drug
  • Acute angle closure of right eye due to congenital malformation of angle of anterior chamber of right eye
  • Acute angle closure of right eye due to intraocular neoplasm
  • Acute angle closure of right eye due to neovascularization
  • Acute angle closure of right eye due to uveitis
  • Angle closure of right eye caused by drug
  • Angle closure of right eye due to congenital malformation of angle of anterior chamber of right eye
  • Angle closure of right eye due to intraocular neoplasm
  • Angle closure of right eye due to iridocorneal endothelial syndrome
  • Angle closure of right eye due to neovascularization
  • Angle closure of right eye due to uveitis
  • Drug-induced acute angle closure
  • Narrow angle of anterior chamber of right eye
  • Narrow angle of right eye
  • Phacomorphic secondary acute angle closure
  • Phacomorphic secondary acute angle closure of right eye
  • Postoperative acute angle closure
  • Postoperative acute angle closure of right eye
  • Postoperative angle closure of right eye
  • Primary angle closure suspect
  • Primary angle closure suspect of right eye
  • Secondary acute angle closure due to neovascularization
  • Secondary acute angle closure due to uveitis
  • Secondary acute angle closure of right eye
  • Secondary angle closure due to neovascularization
  • Secondary angle closure due to uveitis
  • Secondary angle closure of right eye
  • Secondary angle-closure - synechial
  • Secondary angle-closure due to iridocorneal endothelial syndrome
  • Secondary angle-closure of right eye - synechial

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 H40.031 to ICD-9-CMHistory

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

ICD-9-CM
365.02 Anatomical narrow angle
Approximate The match is approximate rather than exact.

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 H40.031Overview

Is H40.031 (Anatomical narrow angle) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report anatomical narrow angle, right eye on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does H40.031 group to?

When anatomical narrow angle, right eye 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 H40.031?

Under the General Equivalence Mappings, anatomical narrow angle, right eye converts to ICD-9-CM 365.02 (anatomical narrow angle). 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.