ICD-10 Code H18.6 – Keratoconus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H18.6 – Keratoconus
What it is
Keratoconus is a noninflammatory corneal disorder in which the cornea thins and bulges into a cone-like shape. This distortion can cause irregular astigmatism and reduced visual clarity.
Clinical signs
Typical findings include progressive visual blurring, increasing astigmatism, and corneal thinning or steepening on exam. Clinical features vary; refer to documentation.
When to use this code
Use H18.6 when the record clearly documents keratoconus as the diagnosis, including suspected progression or established disease. You may also use it when the provider describes corneal cone deformity with compatible findings. Check documentation if the note only mentions refractive error without confirming keratoconus.
Do not use for
Do not use this code for nonspecific corneal astigmatism, corneal scarring, or other corneal disorders without keratoconus. If the diagnosis is uncertain, check documentation.
Coding tip
Code keratoconus only when the provider documents it explicitly or the record clearly supports the diagnosis.