ICD-10-CM 2027
ICD-10 code for iris cyst
Idiopathic cysts of iris, ciliary body or anterior chamber, unspecified eye
From the official ICD-10-CM alphabetic index entry “Cyst (colloid) (mucous) (simple) (retention) › iris”. Page updated September 29, 2026.
About coding iris cyst
The ICD-10-CM code for iris cyst is H21.309 (Idiopathic cysts of iris, ciliary body or anterior chamber, unspecified eye). The official index lists 6 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on H21.309.
Within H21.30, choose H21.309 (unspecified eye) only when documentation doesn't support a more specific option: right eye (H21.301), left eye (H21.302) and bilateral (H21.303).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 124 (Other Disorders of the Eye with MCC or Thrombolytic Agent, relative weight 1.2471) and DRG 125 (Other Disorders of the Eye without MCC, relative weight 0.7702), in MDC 02 (Diseases and Disorders of the Eye), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific iris cyst codes (official index)
- exudative H21.31 — Exudative cysts of iris or anterior chamber
- idiopathic H21.30 — Idiopathic cysts of iris, ciliary body or anterior chamber
- implantation H21.32 — Implantation cysts of iris, ciliary body or anterior chamber
- parasitic H21.33 — Parasitic cyst of iris, ciliary body or anterior chamber
- pars plana (primary) H21.34 — Primary cyst of pars plana
- exudative H21.35 — Exudative cyst of pars plana
Common questions about iris cyst ICD-10 codes
What is the ICD-10 code for iris cyst?
- H21.309 — Idiopathic cysts of iris, ciliary body or anterior chamber, unspecified eye. More specific codes apply when the documentation supports them: H21.31, H21.30, H21.32, H21.33 and others below.
What is the ICD-10 code for exudative iris cyst?
- H21.31 — Exudative cysts of iris or anterior chamber (header code; choose a more specific subcode).
What is the ICD-10 code for idiopathic iris cyst?
- H21.30 — Idiopathic cysts of iris, ciliary body or anterior chamber (header code; choose a more specific subcode).
What is the ICD-10 code for implantation iris cyst?
- H21.32 — Implantation cysts of iris, ciliary body or anterior chamber (header code; choose a more specific subcode).
What is the ICD-10 code for parasitic iris cyst?
- H21.33 — Parasitic cyst of iris, ciliary body or anterior chamber (header code; choose a more specific subcode).
What is the ICD-10 code for pars plana iris cyst?
- H21.34 — Primary cyst of pars plana (header code; choose a more specific subcode).
Is H21.309 billable?
- Yes. H21.309 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can H21.309 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict H21.309 as a principal diagnosis.
Is H21.309 a CC or MCC?
- No. H21.309 is neither a CC nor an MCC under MS-DRG v44.0.