ICD-10 Code H40.839 – Aqueous misdirection, unspecified eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H40.839 – Aqueous misdirection, unspecified eye
What it is
This code identifies aqueous misdirection, also called malignant glaucoma, in an unspecified eye. It describes abnormal forward movement of aqueous humor that raises intraocular pressure and shallows the anterior chamber.
Clinical signs
Typical findings include a shallow or flat anterior chamber, elevated intraocular pressure, and blurred vision or eye pain. Clinical features vary; refer to documentation.
When to use this code
Use H40.839 when the provider documents aqueous misdirection but does not specify the affected eye. It also fits when the note confirms the diagnosis without laterality detail. If the record names the right or left eye, code the specified laterality instead.
Do not use for
Do not use this code for other causes of glaucoma, postoperative pressure rise without aqueous misdirection, or unspecified glaucoma diagnoses. Check documentation if the record does not clearly state aqueous misdirection.
Coding tip
Look for provider wording such as malignant glaucoma or aqueous misdirection, and verify that eye laterality is absent before choosing the unspecified code.