ICD-10 Code H18.71 – Corneal ectasia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H18.71 – Corneal ectasia
What it is
H18.71 identifies corneal ectasia, a condition in which the cornea becomes abnormally thin and bulges forward. Use it when the record documents corneal weakening or progressive corneal protrusion.
Clinical signs
Typical findings include corneal thinning, irregular astigmatism, and progressive change in corneal shape. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents corneal ectasia by name, or describes ectatic corneal change consistent with that diagnosis. It may appear after corneal surgery or in progressive corneal disorders, but you should code only what is clearly stated. Check documentation if the chart uses nonspecific terms.
Do not use for
Do not use H18.71 for unrelated corneal scars, edema, or simple refractive error. If the diagnosis is only suspected or not confirmed, do not assign this code.
Coding tip
Verify that the note documents ectasia itself, not just reduced vision or abnormal refraction.