ICD-10 Code H18.509 – Unspecified hereditary corneal dystrophies, unspecified eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H18.509 – Unspecified hereditary corneal dystrophies, unspecified eye
What it is
This code identifies a hereditary corneal dystrophy when the exact subtype is not documented and the affected eye is not specified. Use it for inherited corneal clouding or degeneration of unclear type.
Clinical signs
Clinical features vary; refer to documentation. Findings may include corneal opacity, recurrent visual disturbance, or symptoms consistent with a dystrophic corneal process, but the specific hereditary subtype is not named.
When to use this code
Use H18.509 when the record states a hereditary corneal dystrophy but does not identify the subtype. It also fits when laterality is not documented as right, left, or bilateral. If the clinician names a specific dystrophy, code that condition instead.
Do not use for
Do not use this code for acquired corneal disorders, nonspecific corneal opacity, or clearly documented nonhereditary disease. Check documentation if the chart identifies a more specific corneal dystrophy or laterality.
Coding tip
Confirm both heredity and the unspecified eye status in the note before assigning H18.509.