ICD-10 Code H21.343 – Primary cyst of pars plana, bilateral (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.343 – Primary cyst of pars plana, bilateral
What it is
This code identifies a primary cyst of the pars plana in both eyes. It refers to a bilateral cystic lesion in the ciliary body region, documented as primary rather than secondary.
Clinical signs
Clinical features vary; refer to documentation. It may be found on eye examination or imaging as a cystic lesion near the pars plana, sometimes without symptoms.
When to use this code
Use H21.343 when the provider documents a primary pars plana cyst affecting both eyes. Code it when the diagnosis is confirmed and the record specifies bilateral involvement. If the note only mentions an intraocular cyst without location or laterality, check documentation.
Do not use for
Do not use this code for a unilateral pars plana cyst or a cyst described as secondary. Do not assign it when the chart does not clearly identify the pars plana or bilateral eyes.
Coding tip
Confirm both the anatomic site and laterality in the ophthalmology note before assigning H21.343.