ICD-10-CM > H00-H59 > H15-H22 > H21 > H21.5 > H21.55 H21.55 Recession of chamber angle Non-Billable/Non-Specific Codes H21.551Recession of chamber angle, right eyeH21.552Recession of chamber angle, left eyeH21.553Recession of chamber angle, bilateralH21.559Recession of chamber angle, unspecified eye