ICD-10 Code H51.2 – Internuclear ophthalmoplegia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H51.2 – Internuclear ophthalmoplegia
What it is
H51.2 identifies internuclear ophthalmoplegia, a disorder of eye movement coordination caused by impaired communication between the eyes’ movement centers. It is used when documentation names this specific neurologic eye movement deficit.
Clinical signs
Typical findings include impaired adduction of one eye with horizontal gaze, often with nystagmus of the abducting eye. Clinical features vary; refer to documentation.
When to use this code
Use H51.2 when the record clearly documents internuclear ophthalmoplegia or INO as the diagnosis. It may appear in neurologic evaluations, neuro-ophthalmology notes, or imaging workups when the condition is confirmed or strongly supported. Check documentation if the note only describes diplopia or vague eye movement problems.
Do not use for
Do not use this code for nonspecific double vision, general ophthalmoplegia, or other eye movement disorders without documentation of internuclear ophthalmoplegia. If the diagnosis is uncertain, check documentation.
Coding tip
Confirm that the provider specifically documents internuclear ophthalmoplegia, not just abnormal gaze or diplopia, before assigning H51.2.