What is ICD-10 code H40.231?

H40.231 is the ICD-10-CM diagnosis code for Intermittent angle-closure glaucoma, right eye. A recurring form of glaucoma in the right eye where the drainage angle periodically closes, causing temporary increases in eye pressure. It belongs to the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59). H40.231 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. H40.231 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. H40.231 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. H40.231 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 H40.231?

H40.231 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 H40.231 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 H40.231?

Distinguish this from acute angle-closure glaucoma; intermittent episodes may resolve spontaneously or with treatment Document the frequency and severity of episodes to support medical necessity for ongoing management

H40.231 ICD-10 Code: Intermittent angle-closure

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupH40.231Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

H40.231

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

Intermittent angle-closure glaucoma, right eye

A recurring form of glaucoma in the right eye where the drainage angle periodically closes, causing temporary increases in eye pressure.

Buddy Insight

Intermittent angle-closure glaucoma of the right eye is a form of glaucoma where the drainage angle periodically closes, causing episodic elevation of intraocular pressure.

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

Basket needed

Compare selected patient codes to show trumped or trumps impact.

Code Book Path

Official

H40.2Primary angle-closure glaucoma

H40.23Intermittent angle-closure glaucoma

H40.231Intermittent angle-closure glaucoma, right eye

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for H40.231 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for H40.231 in this effective period.

Related Child Codes

Official

H40.232Intermittent angle-closure glaucoma, left eye

H40.233Intermittent angle-closure glaucoma, bilateral

H40.239Intermittent angle-closure glaucoma, unspecified eye

Includes

Official

ICD-10-CM does not list Includes notes for H40.231 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for H40.231 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for H40.231 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for H40.231 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for H40.231 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Gonioscopy findings documenting intermittent angle closure in the right eye

Intraocular pressure measurements including during and between episodes

Documentation of episodic symptoms (halos, blurred vision, eye pain)

Optic nerve assessment and visual field testing

MEAT Support

HCC Buddy guidance

Gonioscopy findings documenting intermittent angle closure in the right eye

Intraocular pressure measurements including during and between episodes

Documentation of episodic symptoms (halos, blurred vision, eye pain)

Optic nerve assessment and visual field testing

Audit Caution

HCC Buddy guidance

Confusing intermittent angle closure with acute angle-closure crisis, which is a medical emergency

Using open-angle glaucoma codes when angle-closure mechanism has been documented on gonioscopy

Not differentiating between intermittent and chronic angle-closure based on gonioscopy findings

Coding as glaucoma suspect when actual intermittent angle closure with pressure elevation has been documented

Common Mistakes

HCC Buddy guidance

H40.211 — Acute angle-closure glaucoma, right eye: acute crisis with sustained angle closure, more urgent

H40.221 — Chronic angle-closure glaucoma, right eye: persistent angle closure, not intermittent

H40.1111 — Primary open-angle glaucoma, right eye, mild stage: different mechanism, open angles

H40.031 — Anatomical narrow angle, right eye: narrow angles without actual closure or pressure elevation

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 H40.231 an HCC code?

No. H40.231 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.

MEAT Criteria for H40.231

For H40.231to 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 H40.231 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

H40.231 is the ICD-10-CM diagnosis code for intermittent angle-closure glaucoma, right eye. A recurring form of glaucoma in the right eye where the drainage angle periodically closes, causing temporary increases in eye pressure. H40.231 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering glaucoma (h40-h42).

H40.231 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.

In the RxHCC model, H40.231 maps to RxHCC 244 (Glaucoma, Other) with a RAF weight of 0.0. No V28, V24, or ESRD HCC mappings exist. The RxHCC mapping captures the medication management requirements for angle-closure glaucoma, which may differ from open-angle treatment regimens. The distinction between RxHCC 243 (Glaucoma) and 244 (Glaucoma, Other) affects medication cost predictions.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for H40.231 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Distinguish this from acute angle-closure glaucoma; intermittent episodes may resolve spontaneously or with treatment
•Document the frequency and severity of episodes to support medical necessity for ongoing management

Clinical Significance

Intermittent angle-closure glaucoma of the right eye is a form of glaucoma where the drainage angle periodically closes, causing episodic elevation of intraocular pressure. Between episodes, the angle may appear open. This condition carries risk of acute angle-closure crisis, which is an ophthalmic emergency. Identification and prophylactic treatment (typically laser peripheral iridotomy) are essential to prevent permanent vision loss.

Documentation Requirements

✓Gonioscopy findings documenting intermittent angle closure in the right eye
✓Intraocular pressure measurements including during and between episodes
✓Documentation of episodic symptoms (halos, blurred vision, eye pain)
✓Optic nerve assessment and visual field testing
✓Treatment plan including prophylactic laser peripheral iridotomy status

Commonly Confused Codes

•H40.211: Acute angle-closure glaucoma, right eye: acute crisis with sustained angle closure, more urgent
•H40.221: Chronic angle-closure glaucoma, right eye: persistent angle closure, not intermittent
•H40.1111: Primary open-angle glaucoma, right eye, mild stage: different mechanism, open angles
•H40.031: Anatomical narrow angle, right eye: narrow angles without actual closure or pressure elevation