Keratoconus, unstable, bilateral

This code signifies a progressive, non-inflammatory thinning and bulging of the cornea into a cone-like shape, affecting both eyes, where the condition is actively worsening. This instability often leads to significant visual distortion and reduced visual acuity.

Apply this code when documentation indicates bilateral keratoconus with evidence of progression, such as increasing corneal steepness, thinning, or worsening vision despite corrective lenses. This is typically supported by ophthalmological examination findings, including topography and pachymetry measurements over time.

• Ensure documentation explicitly states "unstable" or provides evidence of progression for both eyes.
• Distinguish from stable keratoconus (H18.603) or keratoconus affecting only one eye.
• Consider sequencing with codes for associated complications, such as corneal hydrops, if present.