What is ICD-10 code H42?

H42 is the ICD-10-CM diagnosis code for Glaucoma in diseases classified elsewhere. Glaucoma that develops as a result of another disease or condition affecting the eye. It belongs to the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59). H42 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. H42 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

H42 does not map to a payment HCC under the CMS-HCC V28 or V24 community risk adjustment model, but it does map under the Part D RxHCC model (Glaucoma, Other). The CMS-HCC ESRD model applies to beneficiaries with end-stage renal disease, and the Part D RxHCC model drives the prescription-drug (Part D) risk score, so H42 can still affect risk-adjusted payment for those populations even though it carries no V28/V24 community RAF.

Yes. H42 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. H42 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for H42?

H42 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither community model rewards H42 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's V28/V24 community RAF score in either version. It does, however, map under the Part D RxHCC model (Glaucoma, Other), which affects the ESRD and/or Part D (RxHCC) risk scores. Coders should check whether provider documentation supports a more specific child code that does map to a community payment HCC.

What should coders know when reporting H42?

This code requires a secondary diagnosis code for the underlying disease causing the glaucoma Common underlying conditions include diabetes, inflammation, or vascular disorders; ensure both conditions are coded

H42: Glaucoma in diseases classified elsewhere — ICD-10

ICD-10-CM Code View

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Code lookupH42Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the eye and adnexa (H00-H59) / Glaucoma (H40-H42)

H42

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Glaucoma in diseases classified elsewhere

Glaucoma that develops as a result of another disease or condition affecting the eye.

Buddy Insight

This manifestation code identifies glaucoma occurring secondary to systemic or other classified diseases, such as diabetes mellitus, amyloidosis, Lowe syndrome, or other metabolic disorders.

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

N/A

—

Not risk-adjusted for this model/period.

Not mapped

RXHCC

Mapped

HCC 244

Glaucoma, Other

RAF 0.067

Code Book Path

Official

H4Glaucoma (H40-H42)

H42Glaucoma in diseases classified elsewhere

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for H42 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for H42 in this effective period.

Related Child Codes

Official

ICD-10-CM does not list child codes under H42 for this display context.

Includes

Official

ICD-10-CM does not list Includes notes for H42 in this effective period.

Excludes 1

Official

glaucoma (in) onchocerciasis (B73.02)
glaucoma (in) syphilis (A52.71)
glaucoma (in) tuberculous (A18.59)
neovascular secondary angle closure glaucoma (H40.84-)

Code First

Official

underlying condition, such as:
amyloidosis (E85.-)
aniridia (Q13.1)
glaucoma (in) diabetes mellitus (E08.39, E09.39, E10.39, E11.39, E13.39)
Lowe's syndrome (E72.03)

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for H42 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for H42 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documented diagnosis of glaucoma as a manifestation of an underlying systemic disease

Identification and documentation of the underlying disease (e.g., diabetes, amyloidosis, Lowe syndrome)

Confirmation that glaucoma is causally related to the underlying condition

Intraocular pressure measurement

MEAT Support

HCC Buddy guidance

Documented diagnosis of glaucoma as a manifestation of an underlying systemic disease

Identification and documentation of the underlying disease (e.g., diabetes, amyloidosis, Lowe syndrome)

Confirmation that glaucoma is causally related to the underlying condition

Intraocular pressure measurement

Audit Caution

HCC Buddy guidance

Sequencing H42 as the primary code — it is a manifestation code and must always follow the underlying disease code

Using H42 without coding the underlying systemic condition — both codes are required

Coding H42 when the glaucoma is secondary to an eye disease rather than a systemic disease — use H40.4x-H40.6x instead

Confusing H42 with primary glaucoma that happens to coexist with a systemic disease — there must be a causal link

Common Mistakes

HCC Buddy guidance

H40.40-H40.43 — Glaucoma secondary to eye inflammation (use for uveitic glaucoma, not systemic disease)

H40.50-H40.53 — Glaucoma secondary to other eye diseases (use for other ocular conditions causing glaucoma)

H40.60-H40.63 — Glaucoma secondary to drugs (use when medication is the cause)

H40.89 — Other specified glaucoma (use when glaucoma type is specified but not secondary to a classified disease)

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is H42 an HCC code?

H42 is not in the CMS-HCC V28 or V24 community payment model, but it does map to Glaucoma, Other under the Part D RxHCC model.

HCC Category Mapping

RxHCCHCC 244, Glaucoma, Other

0.067

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work H42 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for H42

For H42to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed H42 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

H42 is the ICD-10-CM diagnosis code for glaucoma in diseases classified elsewhere. Glaucoma that develops as a result of another disease or condition affecting the eye. H42 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering glaucoma (h40-h42).

H42 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

This code does not map to a CMS-HCC V28 payment category. Capture depends on documentation that supports the diagnosis; verify the HCC assignment against the current CMS mapping for the applicable payment year. Coders reviewing H42 should check whether additional documentation would support a more specific child code in the same hierarchy that does map to a payment HCC, capturing the correct specificity is the highest-impact RAF improvement available within accurate coding.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for H42 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This code requires a secondary diagnosis code for the underlying disease causing the glaucoma
•Common underlying conditions include diabetes, inflammation, or vascular disorders; ensure both conditions are coded

Clinical Significance

This manifestation code identifies glaucoma occurring secondary to systemic or other classified diseases, such as diabetes mellitus, amyloidosis, Lowe syndrome, or other metabolic disorders. As a manifestation code, H42 must always be sequenced after the underlying disease code. Capturing this relationship is important for understanding the full clinical picture and comorbidity burden of the patient.

Documentation Requirements

✓Documented diagnosis of glaucoma as a manifestation of an underlying systemic disease
✓Identification and documentation of the underlying disease (e.g., diabetes, amyloidosis, Lowe syndrome)
✓Confirmation that glaucoma is causally related to the underlying condition
✓Intraocular pressure measurement
✓Optic nerve evaluation
✓Code the underlying disease first, then H42 as the manifestation code

Excludes 1, Do NOT code together

glaucoma (in) onchocerciasis (B73.02)
glaucoma (in) syphilis (A52.71)
glaucoma (in) tuberculous (A18.59)
neovascular secondary angle closure glaucoma (H40.84-)

Code First

underlying condition, such as:
amyloidosis (E85.-)
aniridia (Q13.1)
glaucoma (in) diabetes mellitus (E08.39, E09.39, E10.39, E11.39, E13.39)
Lowe's syndrome (E72.03)
Rieger anomaly (Q13.81)
specified metabolic disorder (E70-E88)

Commonly Confused Codes

•H40.40-H40.43: Glaucoma secondary to eye inflammation (use for uveitic glaucoma, not systemic disease)
•H40.50-H40.53: Glaucoma secondary to other eye diseases (use for other ocular conditions causing glaucoma)
•H40.60-H40.63: Glaucoma secondary to drugs (use when medication is the cause)
•H40.89: Other specified glaucoma (use when glaucoma type is specified but not secondary to a classified disease)
•E11.39: Type 2 diabetes with other diabetic ophthalmic complication (the underlying code that would pair with H42)

Code Hierarchy

└H42Glaucoma in diseases classified elsewhere

H42 ICD-10-CM Code: Glaucoma in diseases classified elsewhere

HCC Buddy Code Card

H42

Is H42 an HCC code?

HCC Category Mapping

MEAT Criteria for H42

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What This Code Means

Coding Tips

Clinical Significance

Documentation Requirements

Excludes 1, Do NOT code together

Code First

Commonly Confused Codes

Code Hierarchy

Work H42 in HCC Buddy