2027 ICD-10-CM Diagnosis Code H51.23Internuclear ophthalmoplegia, bilateral

ICD-10-CM Codes›H00–H59›H49-H52›H51

ICD-10-CM H51.23
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

H51.23 is a billable ICD-10-CM diagnosis code for internuclear ophthalmoplegia, bilateral. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 91 through 93. Coders also document this condition as bilateral internuclear ophthalmoplegia of eyes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Neuro-ophthalmology.

Code Identity

ICD-10-CM Code
H51.23
Billable Status
Yes — Valid for Submission
Code Describes
Internuclear ophthalmoplegia, bilateral
Short Description
Internuclear ophthalmoplegia, bilateral
Same as the full description in the CMS dataset.
Parent Code
H51.2
Internuclear ophthalmoplegia

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH49-H52Disorders of ocular muscles, binocular movement, accommodation and refraction
CategoryH51Other disorders of binocular movement
This CodeH51.23Internuclear ophthalmoplegia, bilateral

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral internuclear ophthalmoplegia of eyes
  • Dissociated gaze palsy
  • Internuclear ophthalmoplegia
  • Internuclear ophthalmoplegia of left eye
  • Internuclear ophthalmoplegia of right eye
  • Wall-eyed bilateral internuclear ophthalmoplegia syndrome

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to H51.23: its own notes plus those printed at block H49-H52 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 Block H49-H52 Disorders of ocular muscles, binocular movement, accommodation and refraction applies to 150 codes
  • nystagmus and other irregular eye movements (H55)
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 H51.23, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming H51.23: its condition is not part of those codes, and both may be reported when the patient has both.

  • H49 Paralytic strabismus
    internuclear ophthalmoplegia (H51.2-) names H51.2-, which includes this code

Clinical ClassificationClinical

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

CCSR EYE006
Neuro-ophthalmology
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Eye Movement Disorders

When you look at an object, you're using several muscles to move both eyes to focus on it. If you have a problem with the muscles, the eyes don't work properly.

Read the full article at MedlinePlus

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

Convert H51.23 to ICD-9-CMHistory

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

ICD-9-CM
378.86 Internucl ophthalmopleg
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 H51.23Overview

What is the ICD-10 code for internuclear ophthalmoplegia, bilateral?

The ICD-10-CM code for internuclear ophthalmoplegia, bilateral is H51.23 (sometimes written as H5123). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is H51.23 (Internuclear ophthalmoplegia) a billable code?

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

What MS-DRG does H51.23 group to?

When internuclear ophthalmoplegia, bilateral is the principal diagnosis on an inpatient stay, it groups to MS-DRG 91, 92, 93, with relative weights from 0.7783 to 1.7050 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of H51.23?

Under the General Equivalence Mappings, internuclear ophthalmoplegia, bilateral converts to ICD-9-CM 378.86 (internucl ophthalmopleg). The mapping is approximate, so confirm the match fits the documentation.