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ICD-10-CM 2027 diagnosis code

H44.421Hypotony of right eye due to ocular fistula

✓ Billable / specific

H44.421 is a valid, billable ICD-10-CM code for hypotony of right eye due to ocular fistula. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About H44.421

H44.421 is the ICD-10-CM diagnosis code for hypotony of right eye due to ocular fistula. It belongs to category H44 (disorders of globe), block H43-H44 (disorders of vitreous body and globe) and chapter 7 (diseases of the eye and adnexa). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within H44.42 (hypotony of eye due to ocular fistula), H44.421 is specifically for hypotony of right eye due to ocular fistula. Related codes cover left eye due to ocular fistula (H44.422), bilateral (H44.423) and unspecified eye due to ocular fistula (H44.429).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 124 (Other Disorders of the Eye with MCC or Thrombolytic Agent, relative weight 1.2471) and DRG 125 (Other Disorders of the Eye without MCC, relative weight 0.7702), in MDC 02 (Diseases and Disorders of the Eye), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 360.32 (ocular fistula causing hypotony).

Notes that apply from higher levels

Instructions written at a parent level also apply to H44.421.

› From H44 Disorders of globe
Includes
  • disorders affecting multiple structures of eye

Broader instructions also apply from Chapter 7: Diseases of the eye and adnexa.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 360.32Ocular fistula causing hypotonyapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about H44.421

Is H44.421 billable?

Yes. H44.421 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can H44.421 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict H44.421 as a principal diagnosis.

Is H44.421 a CC or MCC?

No. H44.421 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does H44.421 group to?

H44.421 is used in the MS-DRG v44.0 logic for MS-DRG 124 (Other Disorders of the Eye with MCC or Thrombolytic Agent) and MS-DRG 125 (Other Disorders of the Eye without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for H44.421?

The CMS General Equivalence Mappings map H44.421 to ICD-9-CM 360.32.