2027 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 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

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 2027 (October 1, 2026 through September 30, 2027) 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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to H18.503: its own notes plus those printed at Chapter 7. A note printed at a category, block or chapter applies to every code under it.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 7 (H00-H59) Diseases of the eye and adnexa applies to 2,677 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • diabetes mellitus related eye conditions (E09.3-, E10.3-, E11.3-, E13.3-)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury (trauma) of eye and orbit (S05.-)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • syphilis related eye disorders (A50.01, A50.3-, A51.43, A52.71)

Notes

General instructions on how these codes are used.

From Chapter 7 (H00-H59) Diseases of the eye and adnexa applies to 2,677 codes
  • Use an external cause code following the code for the eye condition, if applicable, to identify the cause of the eye condition

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

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 Dystrophies, Hereditary

    bilateral hereditary disorders of the cornea, usually autosomal dominant, which may be present at birth but more frequently develop during adolescence and progress slowly throughout life. central macular dystrophy is transmitted as an autosomal recessive defect.

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 H18.503 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 2022–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About H18.503Overview

What is the ICD-10 code for unspecified hereditary corneal dystrophies, bilateral?

The ICD-10-CM code for unspecified hereditary corneal dystrophies, bilateral is H18.503 (sometimes written as H18503). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

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, 2026 through September 30, 2027.

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 125, 124, with relative weights from 0.7699 to 1.2470 depending on complications. Higher weights mean higher Medicare reimbursement.