ICD-10-CM > H00-H59 > H15-H22 > H21 > H21.5 > H21.54 H21.54 Posterior synechiae (iris) Non-Billable/Non-Specific Codes H21.541Posterior synechiae (iris), right eyeH21.542Posterior synechiae (iris), left eyeH21.543Posterior synechiae (iris), bilateralH21.549Posterior synechiae (iris), unspecified eye