Glaucoma in diseases classified elsewhere (H42)
ICD-10 code H42 is used to identify glaucoma occurring as a result of other underlying diseases. This category covers cases where glaucoma is not the primary disorder but develops secondary to systemic or ocular conditions.
The code H42 specifically applies to secondary glaucomas, including those caused by conditions like Lowe syndrome, congenital eye anomalies, uveitis, neovascularization, diabetes mellitus types 1 and 2, vascular disorders, and systemic syndromes. Commonly referred terms such as "secondary angle-closure glaucoma," "neovascular glaucoma due to diabetes," and "glaucoma due to metabolic diseases" all fall under this classification. For medical coders and healthcare professionals, using the ICD-10 code H42 helps link glaucoma diagnoses to the associated systemic or ocular causes. This ensures accurate coding for secondary glaucomas related to conditions like diabetes, systemic syndromes, or inflammatory eye diseases, aiding in proper documentation and management of these complex cases.
Diseases of the eye and adnexa (H00–H59)
Glaucoma (H40-H42)
- H42 Glaucoma in diseases classified elsewhere
Glaucoma in diseases classified elsewhere (H42)
Instructional Notations
Code First
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
- underlying condition, such as:
- amyloidosis E85
- aniridia Q13.1
- glaucoma in diabetes mellitus E08.39 E09.39 E10.39 E11.39 E13.39
- Lowe's syndrome E72.03
- Rieger anomaly Q13.81
- specified metabolic disorder E70 E88
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
