H55 ICD-10-CM Code: Nystagmus and other irregular eye movements

H55 is the ICD-10-CM diagnosis code for nystagmus and other irregular eye movements. H55 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering other disorders of eye and adnexa (h55-h57).

Header codes like H55 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at H55's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.