2026 ICD-10-CM Diagnosis Code H05.123Orbital myositis, bilateral

ICD-10-CM Codes›H00–H59›H00-H05›H05

ICD-10-CM H05.123
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H05.123 is a billable ICD-10-CM diagnosis code for orbital myositis, bilateral. 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. Coders also document this condition as bilateral orbital myositis of eyes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Oculofacial plastics and orbital conditions.

Code Identity

ICD-10-CM Code
H05.123
Billable Status
Yes — Valid for Submission
Code Describes
Orbital myositis, bilateral
Short Description
Orbital myositis, bilateral
Same as the full description in the CMS dataset.
Parent Code
H05.12
Orbital myositis

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH00-H05Disorders of eyelid, lacrimal system and orbit
CategoryH05Disorders of orbit
This CodeH05.123Orbital myositis, bilateral

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral orbital myositis of eyes
  • Orbital myositis
  • Orbital myositis of left eye
  • Orbital myositis of right eye

Clinical ClassificationClinical

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

CCSR EYE008
Oculofacial plastics and orbital conditions
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Orbital Myositis

    inflammation of the extraocular muscle of the eye. it is characterized by swelling which can lead to ischemia, fibrosis, or orbital pseudotumor.

  • Orbital Pseudotumor

    a nonspecific tumor-like inflammatory lesion in the orbit of the eye. it is usually composed of mature lymphocytes; plasma cells; macrophages; leukocytes with varying degrees of fibrosis. orbital pseudotumors are often associated with inflammation of the extraocular muscles (orbital myositis) or inflammation of the lacrimal glands (dacryoadenitis).

  • Orbital Myositis

    a rare form of myositis that affects only the orbital muscles.

Patient EducationClinical

Eye Diseases

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Read the full article at MedlinePlus

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

Convert H05.123 to ICD-9-CMHistory

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

ICD-9-CM
376.12 Orbital myositis
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 H05.123Overview

Is H05.123 (Orbital myositis) a billable code?

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

What MS-DRG does H05.123 group to?

When orbital myositis, bilateral 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 H05.123?

Under the General Equivalence Mappings, orbital myositis, bilateral converts to ICD-9-CM 376.12 (orbital myositis). 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.