2027 ICD-10-CM Diagnosis Code H33.123Parasitic cyst of retina, bilateral

ICD-10-CM Codes›H00–H59›H30-H36›H33

ICD-10-CM H33.123
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

H33.123 is a billable ICD-10-CM diagnosis code for parasitic cyst of retina, bilateral. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 121 through 122. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 29 closely related codes. Coders also document this condition as bilateral parasitic retinal cysts. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Retinal and vitreous conditions.

Code Identity

ICD-10-CM Code
H33.123
Billable Status
Yes — Valid for Submission
Code Describes
Parasitic cyst of retina, bilateral
Short Description
Parasitic cyst of retina, bilateral
Same as the full description in the CMS dataset.
Parent Code
H33.12
Parasitic cyst of retina

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH30-H36Disorders of choroid and retina
CategoryH33Retinal detachments and breaks
This CodeH33.123Parasitic cyst of retina, bilateral

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral parasitic retinal cysts
  • Left parasitic retinal cyst
  • Parasitic cyst of retina
  • Right parasitic retinal cyst
  • Secondary retinal cyst

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to H33.123: its own notes plus those printed at H33.1, H33, and Chapter 7. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From H33.1 Retinoschisis and retinal cysts applies to 16 codes
  • congenital retinoschisis (Q14.1)
  • microcystoid degeneration of retina (H35.42-)
From H33 Retinal detachments and breaks applies to 65 codes

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 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.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name H33.123, its category, or a range that includes it.

Use Additional Code 1

These codes say to use an additional code from the note, and H33.123 is one of the codes named.

  • H44.2C Degenerative myopia with retinal detachment
    code to identify the retinal detachment (H33.-) names H33.-, which includes this code

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR EYE005
Retinal and vitreous conditions
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Parasitic Diseases

Parasites are living things that use other living things - like your body - for food and a place to live. You can get them from contaminated food or water, a bug bite, or sexual contact. Some parasitic diseases are easily treated and some are not.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert H33.123 to ICD-9-CMHistory

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

ICD-9-CM
360.13 Parasitic endophthal NOS
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 H33.123Overview

What is the ICD-10 code for parasitic cyst of retina, bilateral?

The ICD-10-CM code for parasitic cyst of retina, bilateral is H33.123 (sometimes written as H33123). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is H33.123 (Parasitic cyst of retina) a billable code?

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

What MS-DRG does H33.123 group to?

When parasitic cyst of retina, bilateral is the principal diagnosis on an inpatient stay, it groups to MS-DRG 122, 121, with relative weights from 0.7403 to 1.2249 depending on complications. Higher weights mean higher Medicare reimbursement.

Is H33.123 a CC or MCC?

CMS lists H33.123 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 29 closely related codes in its exclusion list.

Can H33.123 be reported with Q14.1?

Not as a rule. The Excludes1 note at H33.1, which applies to H33.123, lists "congenital retinoschisis (Q14.1)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).