2026 ICD-10-CM Diagnosis Code H18.503Unspecified hereditary corneal dystrophies, bilateral

ICD-10-CM Codes›H00–H59›H15-H22›H18

ICD-10-CM H18.503
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H18.503 is a billable ICD-10-CM diagnosis code for unspecified hereditary corneal dystrophies, 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 dystrophy of anterior surface of cornea of eyes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cornea and external disease.

Code Identity

ICD-10-CM Code
H18.503
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified hereditary corneal dystrophies, bilateral
Short Description
Unspecified hereditary corneal dystrophies, bilateral
Same as the full description in the CMS dataset.
Parent Code
H18.50
Unspecified hereditary corneal dystrophies

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH15-H22Disorders of sclera, cornea, iris and ciliary body
CategoryH18Other disorders of cornea
This CodeH18.503Unspecified hereditary corneal dystrophies, bilateral

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral dystrophy of anterior surface of cornea of eyes
  • Bilateral dystrophy of posterior surface of cornea of eyes
  • Bilateral hereditary dystrophy of cornea of eyes
  • Dystrophy of anterior cornea

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

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

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Code History & ChangesHistory

Replacement H18.503 replaces the following previously assigned code(s):

  • H18.50 - Unspecified hereditary corneal dystrophies
FY 2021AddedAdded to the ICD-10-CM code setEffective October 1, 2020.
FY 2022–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About H18.503Overview

Is H18.503 (Unspecified hereditary corneal dystrophies) a billable code?

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

What MS-DRG does H18.503 group to?

When unspecified hereditary corneal dystrophies, 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.

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.