2026 ICD-10-CM Diagnosis Code H16.001Unspecified corneal ulcer, right eye

ICD-10-CM Codes›H00–H59›H15-H22›H16

ICD-10-CM H16.001
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H16.001 is a billable ICD-10-CM diagnosis code for unspecified corneal ulcer, right eye. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 121 through 122. Coders also document this condition as corneal erosion. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cornea and external disease.

Code Identity

ICD-10-CM Code
H16.001
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified corneal ulcer, right eye
Short Description
Unspecified corneal ulcer, right eye
Same as the full description in the CMS dataset.
Parent Code
H16.00
Unspecified corneal ulcer

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH15-H22Disorders of sclera, cornea, iris and ciliary body
CategoryH16Keratitis
This CodeH16.001Unspecified corneal ulcer, right eye

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Corneal erosion
  • Corneal ulcer caused by Acanthamoeba
  • Corneal ulcer of right eye
  • Erosion of cornea of right eye
  • Protozoal corneal ulcer
  • Ulcer of right cornea caused by Acanthamoeba

Clinical ClassificationClinical

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

CCSR EYE001
Cornea and external disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Corneal Ulcer

    loss of epithelial tissue from the surface of the cornea due to progressive erosion and necrosis of the tissue; usually caused by bacterial, fungal, or viral infection.

Patient EducationClinical

Corneal Disorders

Your cornea is the outermost layer of your eye. It is clear and shaped like a dome. The cornea helps to shield the rest of the eye from germs, dust, and other harmful matter. It also helps your eye to focus. If you wear contact lenses, they float on top of your corneas.

Read the full article at MedlinePlus

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

Convert H16.001 to ICD-9-CMHistory

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

ICD-9-CM
370.00 Corneal ulcer NOS
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 H16.001Overview

Is H16.001 (Unspecified corneal ulcer) a billable code?

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

What MS-DRG does H16.001 group to?

When unspecified corneal ulcer, right eye is the principal diagnosis on an inpatient stay, it groups to MS-DRG 121, 122, with relative weights from 0.7858 to 1.1633 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of H16.001?

Under the General Equivalence Mappings, unspecified corneal ulcer, right eye converts to ICD-9-CM 370.00 (corneal ulcer NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.