Glaucoma ICD-10-CM codes

Primary open-angle glaucoma, the most common form, is H40.11- with the sixth character for laterality (1 right, 2 left, 3 bilateral, 9 unspecified) and a seventh character for stage: 0 stage unspecified, 1 mild, 2 moderate, 3 severe, 4 indeterminate. H40.1131 is bilateral POAG, mild stage. Unspecified open-angle glaucoma uses an X placeholder in the sixth position (H40.10X0 through H40.10X4) because it has no laterality. H40.9 is glaucoma, unspecified.

The official guidelines address bilateral glaucoma directly. When both eyes have the same type and stage, assign one bilateral code. When each eye has a different type or a different stage, assign a code for each eye; for subcategories that have no bilateral option, assign a laterality code for each eye with its own stage. If the stage progresses during an admission, report the highest stage documented.

Stage 4 (indeterminate) is reserved for cases where the provider states the stage cannot be clinically determined; stage 0 is used when the documentation is silent. Do not confuse them. Stages are based on the provider's documentation of visual field loss, not on the coder's reading of the field test.

Angle-closure glaucoma is H40.2-: acute angle-closure (H40.21-) has laterality only, while chronic angle-closure (H40.22-) carries the stage character. Glaucoma suspect and ocular hypertension are H40.0- (H40.05- ocular hypertension) and are not glaucoma. Secondary glaucoma due to trauma, inflammation, other eye disorders, or drugs is H40.3- through H40.6- with laterality and stage. H42 (glaucoma in diseases classified elsewhere) requires the underlying disease first.