2027 ICD-10-CM Diagnosis Code H21.343Primary cyst of pars plana, bilateral

ICD-10-CM Codes›H00–H59›H15-H22›H21

ICD-10-CM H21.343
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

H21.343 is a billable ICD-10-CM diagnosis code for primary cyst of pars plana, bilateral. 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 bilateral cyst of ciliary body. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified eye disorders.

Code Identity

ICD-10-CM Code
H21.343
Billable Status
Yes — Valid for Submission
Code Describes
Primary cyst of pars plana, bilateral
Short Description
Primary cyst of pars plana, bilateral
Same as the full description in the CMS dataset.
Parent Code
H21.34
Primary cyst of pars plana

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH15-H22Disorders of sclera, cornea, iris and ciliary body
CategoryH21Other disorders of iris and ciliary body
This CodeH21.343Primary cyst of pars plana, bilateral

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral cyst of ciliary body
  • Bilateral primary cysts of pars plana
  • Cyst of ciliary body of left eye
  • Cyst of ciliary body of right eye
  • Left primary cyst of pars plana
  • Primary cyst of pars plana
  • Right primary cyst of pars plana

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to H21.343: its own notes plus those printed at H21.3, 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.

From H21.3 Cyst of iris, ciliary body and anterior chamber applies to 24 codes
From H21 Other disorders of iris and ciliary body applies to 97 codes
From Chapter 7 (H00-H59) Diseases of the eye and adnexa applies to 2,677 codes
  • 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.

From Chapter 7 (H00-H59) Diseases of the eye and adnexa applies to 2,677 codes
  • 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.

CCSR EYE012
Other specified eye disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

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 H21.343 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
364.63 Primary cyst pars plana
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About H21.343Overview

What is the ICD-10 code for primary cyst of pars plana, bilateral?

The ICD-10-CM code for primary cyst of pars plana, bilateral is H21.343 (sometimes written as H21343). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is H21.343 (Primary cyst of pars plana) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report primary cyst of pars plana, bilateral on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does H21.343 group to?

When primary cyst of pars plana, bilateral 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 H21.343?

Under the General Equivalence Mappings, primary cyst of pars plana, bilateral converts to ICD-9-CM 364.63 (primary cyst pars plana). The mapping is approximate, so confirm the match fits the documentation.