ICD-10 Code H18.609 – Keratoconus, unspecified, unspecified eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H18.609 – Keratoconus, unspecified, unspecified eye
What it is
This code identifies keratoconus when the chart does not specify which eye is affected. Keratoconus is a progressive thinning and cone-like steepening of the cornea that can blur vision.
Clinical signs
Common findings include irregular astigmatism, reduced visual acuity, and distorted or ghosted vision. Clinical features vary; refer to documentation for the affected eye and exam findings.
When to use this code
Use H18.609 when the provider documents keratoconus but does not identify the right or left eye. It also fits when the note confirms keratoconus yet laterality is unavailable or not recorded. If the record names a specific eye, code that more specific option instead.
Do not use for
Do not use this code for other corneal disorders, corneal ectasia from surgery, or nonspecific blurred vision. Check documentation if the diagnosis is uncertain.
Coding tip
Always look for laterality in the assessment, impression, or ophthalmology exam before assigning this unspecified-eye code.