ICD-10-CM > H00-H59 > H40-H42 > H40 > H40.1 > H40.10 H40.10 Unspecified open-angle glaucoma Non-Billable/Non-Specific Codes H40.10X0..., stage unspecifiedH40.10X1..., mild stageH40.10X2..., moderate stageH40.10X3..., severe stageH40.10X4..., indeterminate stage