ICD-10 Code H55.00 – Unspecified nystagmus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H55.00 – Unspecified nystagmus
What it is
H55.00 identifies nystagmus when the chart does not specify the type, cause, or direction. It covers involuntary, repetitive eye movements documented only as unspecified nystagmus.
Clinical signs
Clinical features vary; refer to documentation. Typical notes may describe rhythmic eye movements, oscillopsia, or impaired visual fixation, but you should code only what is recorded.
When to use this code
Use H55.00 when the provider documents nystagmus without further detail, such as horizontal, vertical, congenital, or acquired type. It is also appropriate when the record confirms nystagmus but does not state a cause or subtype. Check documentation if a more specific code is available.
Do not use for
Do not use this code if the record specifies a different nystagmus type or an underlying condition that should be coded instead. Avoid it when the documentation is incomplete and needs clarification.
Coding tip
If the note says only “nystagmus,” code H55.00 unless the provider gives a more specific classification.