2026 ICD-10-CM Diagnosis Code H18.599Other hereditary corneal dystrophies, unspecified eye

ICD-10-CM Codes›H00–H59›H15-H22›H18

ICD-10-CM H18.599
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H18.599 is a billable ICD-10-CM diagnosis code for other hereditary corneal dystrophies, unspecified 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 Cornea and external disease.

Code Identity

ICD-10-CM Code
H18.599
Billable Status
Yes — Valid for Submission
Code Describes
Other hereditary corneal dystrophies, unspecified eye
Short Description
Other hereditary corneal dystrophies, unspecified eye
Same as the full description in the CMS dataset.
Parent Code
H18.59
Other 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 CodeH18.599Other hereditary corneal dystrophies, unspecified eye

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Central cloudy dystrophy of Francois
  • Combined corneal dystrophy
  • Congenital corneal dystrophy
  • Congenital osteodystrophy
  • Congenital stromal corneal dystrophy
  • Crocodile shagreen of cornea
  • Crystalline corneal dystrophy
  • Fleck corneal dystrophy
  • Francois syndrome
  • Gelatinous droplike corneal dystrophy
  • Grayson Wilbrandt corneal dystrophy
  • Polymorphous corneal dystrophy
  • Posterior amorphous corneal dystrophy
  • Posterior crocodile shagreen of cornea
  • Pre-descemet's corneal dystrophy
  • Reis-Bucklers' corneal dystrophy
  • Ring-like corneal dystrophy
  • Schnyder crystalline cornea dystrophy
  • Stromal corneal dystrophy
  • Subepithelial mucinous corneal dystrophy
  • Thiel-Behnke corneal dystrophy

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

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

Code History & ChangesHistory

Replacement H18.599 replaces the following previously assigned code(s):

  • H18.59 - Other 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 H18.599Overview

Is H18.599 (Other hereditary corneal dystrophies) a billable code?

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

What MS-DRG does H18.599 group to?

When other hereditary corneal dystrophies, unspecified 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.

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.