ICD-10 Code H18.623 – Keratoconus, unstable, bilateral (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H18.623 – Keratoconus, unstable, bilateral
What it is
H18.623 identifies keratoconus affecting both eyes when the corneal cone is unstable or changing. Use it for documented bilateral keratoconus with progression, fluctuation, or other instability noted in the record.
Clinical signs
Typical findings include bilateral corneal thinning and cone-shaped protrusion with irregular astigmatism and reduced visual quality. Clinical features vary; refer to documentation for signs of progression or instability.
When to use this code
Use this code when the provider documents keratoconus in both eyes and specifically notes instability, progression, or an unstable course. It also fits follow-up visits where the diagnosis remains active and bilateral. If the chart does not clearly state bilateral involvement or instability, check documentation.
Do not use for
Do not use H18.623 for stable keratoconus without documented instability. Do not assign it if only one eye is affected or if the note describes another corneal disorder. Check documentation.
Coding tip
Code the laterality and stability exactly as documented; bilateral unstable keratoconus is not the same as unspecified or stable disease.