ICD-10 Code H18.622 – Keratoconus, unstable, left eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H18.622 – Keratoconus, unstable, left eye
What it is
This code identifies keratoconus affecting the left eye when the cornea is unstable or changing. It indicates a progressive corneal thinning and steepening disorder documented as unstable.
Clinical signs
Clinical features may include irregular astigmatism, blurred or distorted vision, and corneal thinning or cone-like protrusion. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents keratoconus in the left eye and specifically notes it as unstable, progressive, or changing. Apply it for ophthalmology assessments, follow-up visits, or problem lists that clearly identify the left eye.
If the record only says keratoconus without laterality or stability, check documentation before assigning this code. Do not assume instability from treatment history alone.
Do not use for
Do not use this code for stable keratoconus, unspecified eye, or keratoconus documented only in the right eye. Do not use it when the diagnosis is uncertain; check documentation.
Coding tip
Verify both laterality and instability in the note before coding H18.622.