ICD-10 Code H49.40 – Progressive external ophthalmoplegia, unspecified eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H49.40 – Progressive external ophthalmoplegia, unspecified eye
What it is
H49.40 identifies progressive external ophthalmoplegia affecting an unspecified eye. It is used when the record documents progressive weakness of the extraocular muscles but does not specify right, left, or both eyes.
Clinical signs
Typical findings include slowly worsening limitation of eye movements and ptosis. Clinical features vary; refer to documentation for laterality and any associated neurologic or mitochondrial features.
When to use this code
Use this code when the provider documents progressive external ophthalmoplegia and does not identify the affected eye. It also fits notes that describe chronic, progressive ophthalmoparesis without a more specific eye designation. If the record specifies laterality, code to that level instead.
Do not use for
Do not use it when the chart names a different cause of ophthalmoplegia or when the condition is not progressive. Check documentation if the record is incomplete or if another eye disorder better explains the findings.
Coding tip
Verify that “progressive external ophthalmoplegia” is explicitly documented before assigning H49.40.