ICD-10 Code H50.55 – Alternating heterophoria (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H50.55 – Alternating heterophoria
What it is
H50.55 identifies alternating heterophoria, a latent eye misalignment that may shift between eyes. It means the eyes tend to drift when binocular fusion is interrupted, but alignment is usually maintained when both eyes work together.
Clinical signs
Clinical features vary; refer to documentation. Common findings include intermittent eye drift on cover testing, symptoms of eye strain, or difficulty maintaining single vision during fatigue or near work.
When to use this code
Use this code when the record specifically documents alternating heterophoria as the diagnosis. It may also apply when an eye care provider notes a latent deviation that alternates between eyes and is not described as manifest strabismus. Check documentation if the type of deviation is unclear.
Do not use for
Do not use this code for manifest strabismus, pure phorias without alternation, or nonspecific eye misalignment. If the note only says “eye deviation” or “double vision,” check documentation before coding.
Coding tip
Code H50.55 only when alternating heterophoria is explicitly documented; otherwise, query for the exact ocular alignment diagnosis.