H55.00 Unspecified nystagmus

The ICD-10-CM code for Unspecified nystagmus is H55.00 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

7: Diseases of the eye and adnexa (H00-H59)

Section

H55-H57: Other disorders of eye and adnexa (H55-H57)

Category H55

12 codes (9 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to H55.00:

• Nystagmus

U.S. Hospital Utilization

• An estimated 22,290 U.S. inpatient stays in 2023 included H55.00 among the documented diagnoses.
• 135 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

Glaucoma (TOC entry)

a. Glaucoma .............................................................................................................................. 48

Assigning glaucoma codes (use as many H40 codes as needed)

Assign as many codes from category H40, Glaucoma, as needed to identify the type of glaucoma, the affected eye, and the glaucoma stage.

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)