H49.12
BillableFourth [trochlear] nerve palsy, left eye
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is H49.12 an HCC code?
No. H49.12 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
H49.12 is the ICD-10-CM diagnosis code for fourth [trochlear] nerve palsy, left eye. This condition involves weakness or paralysis of the fourth cranial nerve (trochlear nerve) on the left side, which controls one of the eye muscles responsible for downward and inward eye movement. Patients typically experience difficulty looking down and inward with the affected eye, often causing double vision and head tilting. H49.12 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering disorders of ocular muscles, binocular movement, accommodation and refraction (h49-h52).
H49.12 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 laterality is documented as left eye in the medical record before assigning the 'left eye' component of this code.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for H49.12 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.