ICD-10-CM > H00-H59 > H15-H22 > H21 > H21.3 > H21.34 H21.34 Primary cyst of pars plana Non-Billable/Non-Specific Codes H21.341Primary cyst of pars plana, right eyeH21.342Primary cyst of pars plana, left eyeH21.343Primary cyst of pars plana, bilateralH21.349Primary cyst of pars plana, unspecified eye