H40.10 – Unspecified open-angle glaucoma

ICD-10-CM 2027 diagnosis code · Glaucoma

Non-billable header

ICD-10-CM code H40.10

Code: H40.10 (claims format: H4010)
Description: Unspecified open-angle glaucoma
Billable: No – use a more specific code below
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 7. Diseases of the eye and adnexa (H00-H59)
Block: H40-H42 Glaucoma
Parent codes: H40 › H40.1

Billable codes under H40.10

H40.10 is a header code and cannot be used on claims. Choose the most specific code:

7th character values

Codes in this category need a 7th character to describe the encounter or episode of care (use placeholder X for empty positions).

Character	Meaning
`0`	stage unspecified
`1`	mild stage
`2`	moderate stage
`3`	severe stage
`4`	indeterminate stage

Notes for H40.10

7th character note:

One of the following 7th characters is to be assigned to code H40.10 to designate the stage of glaucoma

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

H40 – Glaucoma

Excludes1 (not coded here):

absolute glaucoma (H44.51-)
congenital glaucoma (Q15.0)
traumatic glaucoma due to birth injury (P15.3)

Index terms for H40.10

Entries in the ICD-10-CM alphabetic index that lead to this code:

Glaucoma, open angle

Related codes in H40.1

Frequently asked questions

What is ICD-10 code H40.10?

H40.10 is the ICD-10-CM code for unspecified open-angle glaucoma, in the block H40-H42 (Glaucoma).

Is H40.10 a billable code?

No. H40.10 is a header code with more specific child codes; report one of the billable codes listed above.

What category does H40.10 belong to?

It belongs to category H40 – Glaucoma.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.