ICD-10 Code H21.242 – Degeneration of pupillary margin, left eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.242 – Degeneration of pupillary margin, left eye
What it is
Use this code for degenerative change affecting the pupillary margin of the left iris. It identifies a localized structural abnormality, not a general eye complaint.
Clinical signs
Documentation may note irregular or atrophic pupillary margin changes on the left side. Clinical features vary; refer to documentation.
When to use this code
Assign H21.242 when the provider specifically documents degeneration of the pupillary margin in the left eye. Use it for a confirmed diagnosis, such as an ophthalmology exam describing left-sided pupillary margin degeneration. If the record only says “iris abnormality” or “pupil changes,” check documentation.
Do not use for
Do not use this code for right eye or bilateral findings, or for nonspecific pupillary abnormalities without degeneration. Check documentation.
Coding tip
Verify laterality carefully; H21.242 is left eye only.