2027 ICD-10-CM Diagnosis Code H46.12Retrobulbar neuritis, left eye
ICD-10-CM Codes›H00–H59›H46-H47›H46
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Chronic Condition
H46.12 is a billable ICD-10-CM diagnosis code for retrobulbar neuritis, left eye. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 123. 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 12 closely related codes. Coders also document this condition as neuritis of left optic nerve. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Neuro-ophthalmology.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Neuritis of left optic nerve
- Retrobulbar neuritis
- Retrobulbar optic neuritis of left eye
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to H46.12: its own notes plus those printed at H46.1, H46, 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.
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.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name H46.12, its category, or a range that includes it.
Excludes2 2
These codes carry an Excludes2 note naming H46.12: its condition is not part of those codes, and both may be reported when the patient has both.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Optic Neuritis
inflammation of the optic nerve. commonly associated conditions include autoimmune disorders such as multiple sclerosis, infections, and granulomatous diseases. clinical features include retro-orbital pain that is aggravated by eye movement, loss of color vision, and contrast sensitivity that may progress to severe visual loss, an afferent pupillary defect (marcus-gunn pupil), and in some instances optic disc hyperemia and swelling. inflammation may occur in the portion of the nerve within the globe (neuropapillitis or anterior optic neuritis) or the portion behind the globe (retrobulbar neuritis or posterior optic neuritis).
Patient EducationClinical
Optic Nerve Disorders
The optic nerve is a bundle of more than 1 million nerve fibers that carry visual messages. You have one connecting the back of each eye (your retina) to your brain. Damage to an optic nerve can cause vision loss. The type of vision loss and how severe it is depends on where the damage occurs. It may affect one or both eyes.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert H46.12 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About H46.12Overview
What is the ICD-10 code for retrobulbar neuritis, left eye?
The ICD-10-CM code for retrobulbar neuritis, left eye is H46.12 (sometimes written as H4612). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is H46.12 (Retrobulbar neuritis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report retrobulbar neuritis, left eye on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does H46.12 group to?
When retrobulbar neuritis, left eye is the principal diagnosis on an inpatient stay, it groups to MS-DRG 123 (neurological Eye Disorders), which carries a relative weight of 0.8218. Higher weights mean higher Medicare reimbursement.
Is H46.12 a CC or MCC?
CMS lists H46.12 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 12 closely related codes in its exclusion list.
Can H46.12 be reported with A52.15?
Not as a rule. The Excludes1 note at H46.1, which applies to H46.12, lists "syphilitic retrobulbar neuritis (A52.15)". 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).
