ICD-10 Code H40.00 – Preglaucoma, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H40.00 – Preglaucoma, unspecified
What it is
H40.00 identifies a preglaucoma condition without a specified eye or further detail. Use it when documentation notes glaucoma risk, suspicious optic findings, or borderline pressure concerns, but does not confirm a more specific glaucoma diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Commonly noted findings may include suspicious optic nerve appearance, elevated or borderline intraocular pressure, or visual field changes that are not yet diagnostic of glaucoma.
When to use this code
Use H40.00 when the provider documents preglaucoma and gives no laterality or subtype. It may fit follow-up visits for monitoring patients at risk for glaucoma, especially when the record does not support a confirmed glaucoma code.
If the note specifies open-angle, angle-closure, or another defined form, choose the more specific code instead. Check documentation for eye laterality and any progression to established glaucoma.
Do not use for
Do not use this code for confirmed glaucoma, ocular hypertension, or other specified glaucoma types. Also avoid it when the documentation identifies a different eye disorder or provides enough detail for a more specific code.
Coding tip
Code H40.00 only when the record explicitly says preglaucoma and lacks a more specific glaucoma diagnosis.