ICD-10 Code H18.603 – Keratoconus, unspecified, bilateral (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H18.603 – Keratoconus, unspecified, bilateral
What it is
H18.603 identifies keratoconus affecting both eyes when the record does not specify the stage, subtype, or other details. It describes a bilateral corneal thinning disorder that causes the cornea to bulge into a cone shape.
Clinical signs
Clinical features vary; refer to documentation. Common findings include progressive blurred vision, irregular astigmatism, and increased corneal curvature on exam or imaging.
When to use this code
Use this code when the provider documents bilateral keratoconus but does not give a more specific bilateral code or subtype. It also fits cases where both eyes are affected and the note only states “keratoconus, unspecified.”
Check the chart for laterality and specificity before coding. If the record names only one eye, or a different corneal disorder, do not assign H18.603.
Do not use for
Do not use this code for unilateral keratoconus, keratoconus with a specified subtype, or other corneal ectasias. Check documentation if the diagnosis is uncertain or incomplete.
Coding tip
Confirm bilateral involvement and unspecified status in the provider note before assigning H18.603.