H40.1221 Low-tension glaucoma, left eye, mild stage

Billable ICD-10-CM code, FY2026.

Built from H40.122 with 7th character 1 (mild stage).

Applies from H40 Glaucoma

Excludes1 (never code together)

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

Applies from H40.12 Low-tension glaucoma

7th character note

• One of the following 7th characters is to be assigned to each code in subcategory H40.12 to designate the stage of glaucoma

7th character required

• 0 — stage unspecified
• 1 — mild stage
• 2 — moderate stage
• 3 — severe stage
• 4 — indeterminate stage

Risk adjustment (HCC)

• RxHCC V08: HCC 244 — Other Non-Acute Glaucoma

Medicare Code Edits (MCE v43.1 (April 2026))

• Unacceptable principal diagnosis: These codes describe a circumstance which influences care but is not a current illness or injury, or capture only an underlying condition, and are unacceptable as principal diagnosis.

Code annotations containing back-references to H40.1221

Back-references to H40.1

• Type 2 Excludes: H25 Age-related cataract ("capsular glaucoma with pseudoexfoliation of lens (H40.1-)")

Back-references to H40

• Use Additional: E08.39 Diabetes mellitus due to underlying condition with other diabetic ophthalmic complication ("diabetic glaucoma (H40-H42)")
• Use Additional: E09.39 Drug or chemical induced diabetes mellitus with other diabetic ophthalmic complication ("diabetic glaucoma (H40-H42)")
• Use Additional: E10.39 Type 1 diabetes mellitus with other diabetic ophthalmic complication ("diabetic glaucoma (H40-H42)")
• Use Additional: E11.39 Type 2 diabetes mellitus with other diabetic ophthalmic complication ("diabetic glaucoma (H40-H42)")
• Use Additional: E13.39 Other specified diabetes mellitus with other diabetic ophthalmic complication ("diabetic glaucoma (H40-H42)")
• Code First: H26.23 Glaucomatous flecks (subcapsular) ("underlying glaucoma (H40-H42)")

Nearby codes

• H40.1212 Low-tension glaucoma, right eye, moderate stage
• H40.1213 Low-tension glaucoma, right eye, severe stage
• H40.1214 Low-tension glaucoma, right eye, indeterminate stage
• H40.122 Low-tension glaucoma, left eye
• H40.1220 Low-tension glaucoma, left eye, stage unspecified
• H40.1221 Low-tension glaucoma, left eye, mild stage (this code)
• H40.1222 Low-tension glaucoma, left eye, moderate stage
• H40.1223 Low-tension glaucoma, left eye, severe stage
• H40.1224 Low-tension glaucoma, left eye, indeterminate stage
• H40.123 Low-tension glaucoma, bilateral
• H40.1230 Low-tension glaucoma, bilateral, stage unspecified