ICD-10-CM > H00-H59 > H15-H22 > H21 > H21.2 > H21.26 H21.26 Iris atrophy (essential) (progressive) Non-Billable/Non-Specific Codes H21.261Iris atrophy (essential) (progressive), right eyeH21.262Iris atrophy (essential) (progressive), left eyeH21.263Iris atrophy (essential) (progressive), bilateralH21.269Iris atrophy (essential) (progressive), unspecified eye