H18.559 ICD-10-CM Code: Macular corneal dystrophy, 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)
H18.559
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceMacular corneal dystrophy, unspecified eye
Macular corneal dystrophy is a genetic eye condition where cloudy deposits form in the cornea (the clear front part of the eye), affecting vision. This code is used when the condition is present but the specific eye affected is not documented.
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 H18.559 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for H18.559 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for H18.559 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for H18.559 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for H18.559 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for H18.559 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for H18.559 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 H18.559 an HCC code?
No. H18.559 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
H18.559 is the ICD-10-CM diagnosis code for macular corneal dystrophy, unspecified eye. Macular corneal dystrophy is a genetic eye condition where cloudy deposits form in the cornea (the clear front part of the eye), affecting vision. This code is used when the condition is present but the specific eye affected is not documented. H18.559 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).
H18.559 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.
Always attempt to determine which eye is affected (right, left, or bilateral) and use the more specific codes (H18.551, H18.552, or H18.553) rather than the unspecified code when documentation permits.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for H18.559 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Always attempt to determine which eye is affected (right, left, or bilateral) and use the more specific codes (H18.551, H18.552, or H18.553) rather than the unspecified code when documentation permits
- •This is a hereditary condition often diagnosed through genetic testing and slit-lamp examination; ensure documentation clearly supports the diagnosis before coding