What is ICD-10 code H40.9?

H40.9 is the ICD-10-CM diagnosis code for Unspecified glaucoma. Glaucoma where the specific type or cause has not been determined or documented. It belongs to the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59). H40.9 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. H40.9 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.

Yes. H40.9 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. H40.9 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 H40.9?

H40.9 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 model rewards H40.9 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

What should coders know when reporting H40.9?

This is a default code; use only when the type of glaucoma cannot be determined from the record Query the provider to obtain more specific glaucoma classification when possible

H40.9: Unspecified glaucoma — ICD-10

ICD-10-CM Code View

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Code lookupH40.9Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

H40.9

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

Unspecified glaucoma

Glaucoma where the specific type or cause has not been determined or documented.

Buddy Insight

Unspecified glaucoma indicates a diagnosis of glaucoma without further specification of the type, stage, or laterality.

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Not risk-adjusted for this model/period.

RAF 0

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Not risk-adjusted for this model/period.

RAF 0

RXHCC

Mapped

HCC 244

Glaucoma, Other

RAF 0.0

Code Trumping

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Code Book Path

Official

H40Glaucoma

H40.9Unspecified glaucoma

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for H40.9 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for H40.9 in this effective period.

Related Child Codes

Official

H40.0Glaucoma suspect

H40.1Open-angle glaucoma

H40.2Primary angle-closure glaucoma

H40.3Glaucoma secondary to eye trauma

H40.4Glaucoma secondary to eye inflammation

Includes

Official

ICD-10-CM does not list Includes notes for H40.9 in this effective period.

Excludes 1

Official

absolute glaucoma (H44.51-)
congenital glaucoma (Q15.0)
traumatic glaucoma due to birth injury (P15.3)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for H40.9 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for H40.9 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for H40.9 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

At minimum, a documented diagnosis of glaucoma by the treating provider

Intraocular pressure measurement

Optic nerve assessment

Query provider for specific type (open-angle, angle-closure, secondary) and laterality to enable more specific coding

MEAT Support

HCC Buddy guidance

At minimum, a documented diagnosis of glaucoma by the treating provider

Intraocular pressure measurement

Optic nerve assessment

Query provider for specific type (open-angle, angle-closure, secondary) and laterality to enable more specific coding

Audit Caution

HCC Buddy guidance

Using H40.9 when the medical record contains enough information to assign a more specific glaucoma code

Not querying the provider for additional specificity when the record is ambiguous

Coding glaucoma suspect as unspecified glaucoma — suspect and confirmed glaucoma are different clinical concepts

Accepting 'glaucoma' as sufficient documentation without reviewing the full ophthalmology note for type and laterality details

Common Mistakes

HCC Buddy guidance

H40.10-H40.14 — Primary open-angle glaucoma (most common type; code specifically when documented)

H40.20x — Angle-closure glaucoma subtypes (code specifically when documented)

H40.89 — Other specified glaucoma (use when a specific type is documented but has no dedicated code)

H40.001-H40.009 — Glaucoma suspect (use when glaucoma is suspected but not confirmed)

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 H40.9 an HCC code?

No. H40.9 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

HCC Category Mapping

RxHCCHCC 244, Glaucoma, Other

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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 H40.9 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for H40.9

For H40.9to 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 H40.9 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

H40.9 is the ICD-10-CM diagnosis code for unspecified glaucoma. Glaucoma where the specific type or cause has not been determined or documented. H40.9 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering glaucoma (h40-h42).

H40.9 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.

Maps to RxHCC 244 (Glaucoma, Other) with a RAF weight of 0.000 in the prescription drug model. No mapping under CMS-HCC v28, v24, or ESRD models. Using this unspecified code captures the same RxHCC as more specific glaucoma codes, but best practice requires coding to the highest level of specificity supported by documentation. No hierarchies apply.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for H40.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is a default code; use only when the type of glaucoma cannot be determined from the record
•Query the provider to obtain more specific glaucoma classification when possible

Clinical Significance

Unspecified glaucoma indicates a diagnosis of glaucoma without further specification of the type, stage, or laterality. While this code is valid, it represents the lowest specificity level and may indicate incomplete documentation. More specific coding improves clinical data quality and ensures accurate risk stratification for patient management.

Documentation Requirements

✓At minimum, a documented diagnosis of glaucoma by the treating provider
✓Intraocular pressure measurement
✓Optic nerve assessment
✓Query provider for specific type (open-angle, angle-closure, secondary) and laterality to enable more specific coding
✓If specific type cannot be determined, document the clinical reasoning

Commonly Confused Codes

•H40.10-H40.14: Primary open-angle glaucoma (most common type; code specifically when documented)
•H40.20x: Angle-closure glaucoma subtypes (code specifically when documented)
•H40.89: Other specified glaucoma (use when a specific type is documented but has no dedicated code)
•H40.001-H40.009: Glaucoma suspect (use when glaucoma is suspected but not confirmed)