ICD-10 Code H18.22 – Idiopathic Corneal Edema (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H18.22 – Idiopathic corneal edema
What it is
H18.22 identifies corneal swelling of unknown cause. Use it when the record documents idiopathic corneal edema and no underlying eye disease or external cause is stated.
Clinical signs
Typical findings include corneal haze, thickening, and reduced transparency that may affect vision. Clinical features vary; refer to documentation for the exact ophthalmic findings and laterality if recorded.
When to use this code
Use this code when the ophthalmologist documents idiopathic corneal edema as the diagnosis. It is appropriate when the edema is confirmed but the chart does not identify a specific cause such as trauma, surgery, or another corneal disorder.
If the note only says “corneal edema” without a cause, check documentation before assigning H18.22. Code the documented condition as written and ensure any underlying etiology is captured if present.
Do not use for
Do not use this code for corneal edema with a known cause or for postoperative, traumatic, or disease-related edema. Check documentation if the record names a specific corneal disorder or external cause.
Coding tip
Assign H18.22 only when “idiopathic” is clearly documented; otherwise, verify whether another corneal edema code or an underlying cause applies.