2027 ICD-10-CM Diagnosis Code H21.259Iridoschisis, unspecified eye
ICD-10-CM Codes›H00–H59›H15-H22›H21
- Billable — Valid for Submission
- Not Chronic
H21.259 is a billable ICD-10-CM diagnosis code for iridoschisis, unspecified eye. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 124 through 125. Coders also document this condition as iridoschisis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified eye disorders.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Iridoschisis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to H21.259: its own notes plus those printed at H21 and Chapter 7. A note printed at a category, block or chapter applies to every code under it.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- diabetes mellitus related eye conditions (E09.3-, E10.3-, E11.3-, E13.3-)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury (trauma) of eye and orbit (S05.-)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- syphilis related eye disorders (A50.01, A50.3-, A51.43, A52.71)
Notes
General instructions on how these codes are used.
- Use an external cause code following the code for the eye condition, if applicable, to identify the cause of the eye condition
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Eye Diseases
Even if your eyes feel healthy, you could have a problem and not know it. That's why regular eye exams are so important. Refractive errors are the most common type of vision problem that makes it hard to see clearly. But some eye conditions or diseases don't have any symptoms and can lead to a permanent loss of vision.
The full article covers:
- What diseases can affect the eye?
- What are the symptoms of eye diseases?
- Who is more likely to develop eye diseases?
- What are the treatments for eye diseases?
- Can eye diseases be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert H21.259 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About H21.259Overview
What is the ICD-10 code for iridoschisis, unspecified eye?
The ICD-10-CM code for iridoschisis, unspecified eye is H21.259 (sometimes written as H21259). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is H21.259 (Iridoschisis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report iridoschisis, unspecified eye on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does H21.259 group to?
When iridoschisis, unspecified eye is the principal diagnosis on an inpatient stay, it groups to MS-DRG 125, 124, with relative weights from 0.7699 to 1.2470 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of H21.259?
Under the General Equivalence Mappings, iridoschisis, unspecified eye converts to ICD-9-CM 364.52 (iridoschisis). The mapping is approximate, so confirm the match fits the documentation.
