Low-tension glaucoma, unspecified eye, severe stage

This code signifies a form of open-angle glaucoma where optic nerve damage and visual field loss occur despite intraocular pressure (IOP) being within the statistically normal range. It indicates a severe stage of the disease, implying significant and irreversible vision impairment.

Use this code when documentation confirms a diagnosis of low-tension glaucoma, with no specific laterality indicated, and the ophthalmologist has explicitly documented the disease as being in a severe stage. Supporting documentation would include visual field tests showing extensive defects, optic nerve head damage, and IOP readings consistently within normal limits.

• Ensure the medical record clearly specifies "low-tension" or "normal-tension" glaucoma, not just general open-angle glaucoma.
• Always look for explicit documentation of the disease stage (e.g., mild, moderate, severe, indeterminate) as this significantly impacts code selection.
• If laterality is specified (right or left eye), use the more specific codes within the H40.12 category.