H21.509 ICD-10-CM Code: Unspecified adhesions of iris and ciliary body, unspecified eye
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FY 2026 Apr update / Diseases of the eye and adnexa (H00-H59) / Disorders of sclera, cornea, iris and ciliary body (H15-H22)
H21.509
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceUnspecified adhesions of iris and ciliary body, unspecified eye
This code describes scar tissue or abnormal connections that have formed between the iris (the colored part of the eye) and the ciliary body (muscles that control the lens), but the specific type of adhesion is not documented and the affected eye is not specified. This condition can develop after eye inflammation, injury, or surgery.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
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Code Book Path
Inclusion Terms
Official- Synechia (iris) NOS
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for H21.509 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for H21.509 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for H21.509 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for H21.509 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for H21.509 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for H21.509 in this effective period.
Buddy Documentation Tip
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 H21.509 an HCC code?
No. H21.509 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
H21.509 is the ICD-10-CM diagnosis code for unspecified adhesions of iris and ciliary body, unspecified eye. This code describes scar tissue or abnormal connections that have formed between the iris (the colored part of the eye) and the ciliary body (muscles that control the lens), but the specific type of adhesion is not documented and the affected eye is not specified. This condition can develop after eye inflammation, injury, or surgery. H21.509 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering disorders of sclera, cornea, iris and ciliary body (h15-h22).
H21.509 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.
If the eye is specified (right, left, or bilateral), use a more specific code (H21.501, H21.502, or H21.503) rather than the unspecified code H21.509.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for H21.509 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •If the eye is specified (right, left, or bilateral), use a more specific code (H21.501, H21.502, or H21.503) rather than the unspecified code H21.509
- •Review clinical documentation to determine if the adhesion type is specified (such as posterior synechiae or anterior synechiae), as this may allow for a more precise code selection