H21.519 ICD-10-CM Code: Anterior synechiae (iris), 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)
H21.519
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceAnterior synechiae (iris), unspecified eye
Anterior synechiae refers to abnormal adhesions (scar tissue connections) between the iris and the cornea or lens in the eye. This condition can restrict eye movement and potentially affect vision or eye pressure.
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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Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for H21.519 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for H21.519 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for H21.519 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for H21.519 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for H21.519 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for H21.519 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for H21.519 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 H21.519 an HCC code?
No. H21.519 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
H21.519 is the ICD-10-CM diagnosis code for anterior synechiae (iris), unspecified eye. Anterior synechiae refers to abnormal adhesions (scar tissue connections) between the iris and the cornea or lens in the eye. This condition can restrict eye movement and potentially affect vision or eye pressure. H21.519 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).
H21.519 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.
Verify documentation specifies 'unspecified eye' before assigning code H21.519; if the eye is documented as right, left, or bilateral, use the more specific codes H21.511 (right eye) or H21.512 (left eye).
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for H21.519 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation specifies 'unspecified eye' before assigning code H21.519; if the eye is documented as right, left, or bilateral, use the more specific codes H21.511 (right eye) or H21.512 (left eye)
- •Anterior synechiae is often a complication of uveitis, trauma, or surgery, so review the medical record for the underlying cause which may need to be coded separately