H40.00 – Preglaucoma, unspecified

ICD-10-CM 2027 diagnosis code · Glaucoma

Non-billable header

ICD-10-CM code H40.00

Code: H40.00 (claims format: H4000)
Description: Preglaucoma, unspecified
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 › H40.0

Billable codes under H40.00

H40.00 is a header code and cannot be used on claims. Choose the most specific code:

H40.001 – Preglaucoma, unspecified, right eyeBillable
H40.002 – Preglaucoma, unspecified, left eyeBillable
H40.003 – Preglaucoma, unspecified, bilateralBillable
H40.009 – Preglaucoma, unspecified, unspecified eyeBillable

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 H40.00

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

Related codes in H40.0

Frequently asked questions

What is ICD-10 code H40.00?

H40.00 is the ICD-10-CM code for preglaucoma, unspecified, in the block H40-H42 (Glaucoma).

Is H40.00 a billable code?

No. H40.00 is a header code with more specific child codes; report one of the billable codes listed above.

What category does H40.00 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.