In simple words: This refers to a general diagnosis of glaucoma where the specific type isn't known. Glaucoma involves increased pressure in the eye that can harm the optic nerve and affect vision.

This code is used when the type of glaucoma is not specified or further documented.It indicates a condition where the pressure inside the eye is increased, potentially damaging the optic nerve and leading to vision loss or blindness. The specific cause or type of glaucoma is unknown.

Example 1: A patient presents with elevated intraocular pressure but without specific signs or symptoms indicating a particular type of glaucoma. Until further testing can determine the specific type, H40.9 is used., A patient with a history of glaucoma presents for a follow-up appointment, but documentation in the medical record does not specify the type of glaucoma. H40.9 may be used if clarification cannot be obtained., A patient is referred to an ophthalmologist with a suspected glaucoma diagnosis, but the referring physician does not specify the type.H40.9 is used initially until a definitive diagnosis can be made by the ophthalmologist.

Documentation should include intraocular pressure readings, visual field test results, optic nerve assessment, and any relevant symptoms or signs. If any previous testing or treatment for glaucoma exists, it should also be documented, even if the specific type is not explicitly stated.

** If applicable, use an external cause code following H40.9 to identify the cause of the glaucoma.For example, if the glaucoma is due to a drug, a code from the T36-T50 category would be used as a secondary code.