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H18.55 ICD-10-CM Code: Macular corneal dystrophy

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Billing Status: NO. This is a non-billable ICD-10-CM code: report a more specific billable code beneath it.

Not billable · FY2027A non-billable heading in the tabular list: report a more specific code beneath it.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too, and is marked with where it comes from.

The tabular list publishes no instructional note for this code itself.

Where it sits Source: CMS/NCHS

Under:Chapter 7: Diseases of the Eye and AdnexaH15-H22 Disorders of sclera, cornea, iris and ciliary bodyH18 Other disorders of corneaH18.5 Hereditary corneal dystrophies

Codes under H18.55 (4)

  • H18.551Macular corneal dystrophy, right eyeBillable
  • H18.552Macular corneal dystrophy, left eyeBillable
  • H18.553Macular corneal dystrophy, bilateralBillable
  • H18.559Macular corneal dystrophy, unspecified eyeBillable

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Coder workflow for H18.55

MedCoder structured workflow — derived from this code’s own official record

Before you code H18.55

  1. H18.55 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

    ReviewH18.551, H18.552, H18.553, H18.559

    See the relationships section · Guide: How to choose an ICD-10-CM code →

Choose the right path

  1. Does the documentation support one of the more specific codes beneath H18.55?
    Yes → Select that code and continue the checks below on its own page.
    No → H18.55 cannot be reported as written. Where the codes beneath it include an unspecified code, that code applies when the record goes no further; otherwise query for the missing detail.

    ReviewH18.551, H18.552, H18.553, H18.559

Report the code beneath H18.55 that the documentation supports, not H18.55 itself. Then confirm that code is valid for the date of service on its own page.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Coding context

Guidelines, coding notes, decision aids, relationships (with MS-DRG and CCSR classification), hierarchy, HCC, coverage and the context map: what a coder reaches for after the core. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Code Overview

Macular corneal dystrophy is a non-billable ICD-10-CM category code (H18.55). A more specific billable subcode must be selected for claims submission.

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Verify Before Coding

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder-derived relationships — computed from published CMS and AHRQ datasets

Clinical classification (AHRQ CCSR):EYE001 — Cornea and external disease (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Cornea and external disease).

+809 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Dystrophy, dystrophia”; these codes share that main term but sit in a different category of the Tabular List.

G71.0341 — Limb girdle muscular dystrophy due to alpha sarcoglycan dysfunction (muscular, limb-girdle, R3), G71.0342 — Limb girdle muscular dystrophy due to beta sarcoglycan dysfunction (muscular, limb-girdle, R4), G71.0349 — Limb girdle muscular dystrophy due to other sarcoglycan dysfunction (muscular, limb-girdle, R5), G71.035 — Limb girdle muscular dystrophy due to anoctamin-5 dysfunction (muscular, limb-girdle, R12), G71.036 — Limb girdle muscular dystrophy due to fukutin related protein dysfunction (muscular, limb-girdle, R9), G71.038 — Other limb girdle muscular dystrophy (muscular, limb-girdle, R7), G71.039 — Limb girdle muscular dystrophy, unspecified (Leyden-Möbius), G71.09 — Other specified muscular dystrophies (ocular), G71.11 — Myotonic muscular dystrophy (muscular, myotonic), G90.2 — Horner's syndrome (cervical sympathetic), H31.20 — Hereditary choroidal dystrophy, unspecified (choroid), H31.21 — Choroideremia (choroid, choroideremia), H31.22 — Choroidal dystrophy (central areolar) (generalized) (peripapillary) (choroid, central areolar), H31.23 — Gyrate atrophy, choroid (choroid, gyrate atrophy), H31.29 — Other hereditary choroidal dystrophy (choroid, specified type NEC), H35.50 — Unspecified hereditary retinal dystrophy (retinal), H35.51 — Vitreoretinal dystrophy (vitreoretinal), H35.52 — Pigmentary retinal dystrophy (retinal, pigmentary), H35.53 — Other dystrophies primarily involving the sensory retina (retinal, involving, sensory area), H35.54 — Dystrophies primarily involving the retinal pigment epithelium (tapetoretinal), +20 more

Contextual Map

Every relationship of H18.55 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

Clinical classification (CCSR)

Nearest codes (40)

Change history (2)

Reference

Index terms and tables, published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

Common coding questions

MedCoder editorial

Can H18.55 be billed directly?

No. H18.55 (Macular corneal dystrophy) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder-derived relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder editorial explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "H18.55 — Macular corneal dystrophy." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/h18.55-macular-corneal-dystrophy

Change history

  • FY2021 — October 1, 2020
    Became a non-billable header
    FY2021 changes
  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Macular corneal dystrophy

Nearest Codes in This Family

Official ICD-10-CM classifications closest to H18.55 in its code family, with their registry titles.

View all codes in the H18 family