ICD-10 Code H21.342 – Primary cyst of pars plana, left eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.342 – Primary cyst of pars plana, left eye
What it is
H21.342 identifies a primary cyst of the pars plana in the left eye. It refers to a cystic lesion in the ciliary body region, documented as primary rather than secondary.
Clinical signs
Clinical features vary; refer to documentation. The finding is usually identified on ophthalmic examination, often as a visible or imaging-detected cyst in the pars plana area of the left eye.
When to use this code
Use this code when the provider documents a primary pars plana cyst specifically in the left eye. It is appropriate for confirmed ocular findings recorded on exam, imaging, or specialist assessment. Check documentation if laterality or primary status is unclear.
Do not use for
Do not use this code for cysts in the right eye, bilateral disease, or cysts described as secondary. If the chart does not clearly identify a primary pars plana cyst, check documentation.
Coding tip
Confirm both laterality and the word “primary” in the ophthalmology note before assigning H21.342.