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ICD-10-CM 2027 diagnosis code

H21.56Pupillary abnormalities

Not billable — use a more specific code

H21.56 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About H21.56

H21.56 is the ICD-10-CM diagnosis code for pupillary abnormalities. It belongs to category H21 (other disorders of iris and ciliary body), block H15-H22 (disorders of sclera, cornea, iris and ciliary body) and chapter 7 (diseases of the eye and adnexa). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

Within H21.5 (other and unspecified adhesions and disruptions of iris and ciliary body), H21.56 is specifically for pupillary abnormalities. Related codes cover unspecified adhesions of iris (H21.50), anterior synechiae (iris) (H21.51), goniosynechiae (H21.52), Iridodialysis (H21.53), posterior synechiae (iris) (H21.54) and recession of chamber angle (H21.55).

To report this condition, pick the subcode that matches the documentation: H21.561 (eye), H21.562 (eye), H21.563 (bilateral) and H21.569 (eye).

Don't report H21.56 together with the conditions in its Excludes1 note: congenital deformity of pupil (Q13.2-).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under H21.56

Coding notes

Applicable toConditions and synonyms classified to this code
  • Deformed pupil
  • Ectopic pupil
  • Rupture of sphincter, pupil
Excludes1Not coded here — never report together with this code
  • congenital deformity of pupil (Q13.2-)

Notes that apply from higher levels

Instructions written at a parent level also apply to H21.56.

› From H21.5 Other and unspecified adhesions and disruptions of iris and ciliary body
Excludes1
› From H21 Other disorders of iris and ciliary body
Excludes2

Broader instructions also apply from Chapter 7: Diseases of the eye and adnexa.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to H21.56.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about H21.56

Is H21.56 billable?

No. H21.56 is a header code. Report one of its more specific subcodes instead.