ICD-10 Code H49.21 – Sixth [abducent] nerve palsy, right eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H49.21 – Sixth [abducent] nerve palsy, right eye
What it is
H49.21 identifies paralysis or weakness of the right sixth cranial nerve, which controls outward movement of the right eye. This causes limited abduction and can lead to horizontal misalignment.
Clinical signs
Typical findings include inability to move the right eye outward, horizontal diplopia, and esotropia that worsens when looking toward the affected side. Clinical features vary; refer to documentation.
When to use this code
Use H49.21 when the record specifically documents sixth nerve palsy affecting the right eye. It may be supported by ophthalmology, neurology, or emergency documentation describing abduction deficit or diplopia.
Do not assign it for nonspecific eye pain, blurred vision alone, or generic cranial nerve palsy without laterality. If the note does not clearly state right-sided involvement, check documentation.
Do not use for
Do not use this code for left or unspecified sixth nerve palsy, or for diplopia without a documented abducent nerve palsy. Check documentation if the cause is recorded instead of the palsy itself.
Coding tip
Verify laterality in the assessment or impression before coding, because sixth nerve palsy codes are side-specific.