2027 ICD-10-CM Diagnosis Code H26.491Other secondary cataract, right eye

ICD-10-CM Codes›H00–H59›H25-H28›H26

ICD-10-CM H26.491
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

H26.491 is a billable ICD-10-CM diagnosis code for other secondary cataract, right 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 after-cataract of right eye. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cataract and other lens disorders.

Code Identity

ICD-10-CM Code
H26.491
Billable Status
Yes — Valid for Submission
Code Describes
Other secondary cataract, right eye
Short Description
Other secondary cataract, right eye
Same as the full description in the CMS dataset.
Parent Code
H26.49
Other secondary cataract

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH25-H28Disorders of lens
CategoryH26Other cataract
This CodeH26.491Other secondary cataract, right eye

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • After-cataract of right eye
  • Posterior capsule opacification not obscuring vision following extraction of cataract
  • Right after-cataract not obscuring vision

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to H26.491: its own notes plus those printed at H26 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 H26 Other cataract applies to 69 codes
  • congenital cataract (Q12.0)

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 H26.491, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming H26.491: they are not reported together with it, unless the two conditions are unrelated.

  • H59 Intraoperative and postprocedural complications and disorders of eye and adnexa, not elsewhere classified
    secondary cataracts (H26.4-) names H26.4-, which includes this code

Clinical ClassificationClinical

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

CCSR EYE002
Cataract and other lens disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Capsule Opacification

    clouding or loss of transparency of the posterior lens capsule, usually following cataract extraction.

Patient EducationClinical

Cataract

A cataract is a clouding of the clear lens inside your eye. This cloudiness blocks light from reaching the back of the eye, making it harder to see clearly. A cataract can affect one or both eyes, but it doesn't spread from one eye to the other.

The full article covers:

  • What are cataracts?
  • What causes cataracts?
  • Who is more likely to develop cataracts?
  • What are the symptoms of cataracts?
  • How are cataracts diagnosed?
  • How are cataracts treated?
  • Can cataracts be prevented?

Read the full article at MedlinePlus

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

Convert H26.491 to ICD-9-CMHistory

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

ICD-9-CM
366.52 After-cataract NEC
Approximate The match is approximate rather than exact.
ICD-9-CM
366.53 Aftr-catar obscur vision
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 H26.491Overview

What is the ICD-10 code for other secondary cataract, right eye?

The ICD-10-CM code for other secondary cataract, right eye is H26.491 (sometimes written as H26491). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is H26.491 (Other secondary cataract) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other secondary cataract, right eye on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does H26.491 group to?

When other secondary cataract, right 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.

Can H26.491 be reported with Q12.0?

Not as a rule. The Excludes1 note at H26, which applies to H26.491, lists "congenital cataract (Q12.0)". 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).

What is the ICD-9 equivalent of H26.491?

Under the General Equivalence Mappings, other secondary cataract, right eye converts to ICD-9-CM 366.52 (after-cataract NEC) and 366.53 (aftr-catar obscur vision). The mapping is approximate, so confirm the match fits the documentation.