2026 ICD-10-CM Diagnosis Code H21.261Iris atrophy (essential) (progressive), right eye

ICD-10-CM Codes›H00–H59›H15-H22›H21

ICD-10-CM H21.261
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H21.261 is a billable ICD-10-CM diagnosis code for iris atrophy (essential) (progressive), 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. Coders also document this condition as atrophy of iris of right eye. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified eye disorders.

Code Identity

ICD-10-CM Code
H21.261
Billable Status
Yes — Valid for Submission
Code Describes
Iris atrophy (essential) (progressive), right eye
Short Description
Iris atrophy (essential) (progressive), right eye
Same as the full description in the CMS dataset.
Parent Code
H21.26
Iris atrophy (essential) (progressive)

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH15-H22Disorders of sclera, cornea, iris and ciliary body
CategoryH21Other disorders of iris and ciliary body
This CodeH21.261Iris atrophy (essential) (progressive), right eye

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Atrophy of iris of right eye
  • Chandler syndrome
  • Iridocorneal endothelial syndrome
  • Iridocorneal endothelial syndrome of right eye
  • Progressive iris atrophy
  • Right essential iris atrophy

Clinical ClassificationClinical

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

CCSR EYE012
Other specified eye disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Iridocorneal Endothelial Syndrome

    a grouping of three closely linked conditions: iris nevus (or cogan-reese) syndrome, chandler syndrome, and essential (progressive) iris atrophy. the most common features of this syndrome are the movement of endothelial cells off the cornea onto the iris leading to corneal swelling, distortion of the iris, and variable degrees of distortion of the pupil. the abnormal cell movement plugs fluid outflow channels of the eye causing glaucoma.

  • Glaucoma

    an ocular disease, occurring in many forms, having as its primary characteristics an unstable or a sustained increase in the intraocular pressure which the eye cannot withstand without damage to its structure or impairment of its function. the consequences of the increased pressure may be manifested in a variety of symptoms, depending upon type and severity, such as excavation of the optic disk, hardness of the eyeball, corneal anesthesia, reduced visual acuity, seeing of colored halos around lights, disturbed dark adaptation, visual field defects, and headaches. (dictionary of visual science, 4th ed)

  • Iridocorneal Endothelial Syndrome

    a group of disorders characterized by the presence of an abnormal inner layer of the cornea. this abnormality results in iris distortion, corneal swelling, pupil distortion, and glaucoma. it usually affects only one eye.

Patient EducationClinical

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Convert H21.261 to ICD-9-CMHistory

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

ICD-9-CM
364.51 Progressive iris atrophy
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 H21.261Overview

Is H21.261 (Iris atrophy (essential) (progressive)) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report iris atrophy (essential) (progressive), right eye on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does H21.261 group to?

When iris atrophy (essential) (progressive), 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 H21.261?

Under the General Equivalence Mappings, iris atrophy (essential) (progressive), right eye converts to ICD-9-CM 364.51 (progressive iris atrophy). 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.