Disorders of optic chiasm in (due to) neoplasm

This code signifies visual field defects or other neurological impairments directly resulting from a tumor affecting the optic chiasm. The optic chiasm is the point where optic nerves from both eyes partially cross, and a lesion here can cause characteristic visual disturbances.

Apply this code when documentation clearly links a patient's optic chiasm disorder, such as bitemporal hemianopsia or other visual field loss, to the presence of a neoplasm. This diagnosis is supported by imaging studies (e.g., MRI, CT) confirming a tumor's proximity to or involvement of the optic chiasm, along with ophthalmological findings.

• Always code the underlying neoplasm first, followed by this code to indicate the manifestation.
• Ensure the documentation explicitly states the optic chiasm disorder is "due to" or "in" the neoplasm, not merely co-occurring.
• Distinguish from other optic nerve disorders not directly caused by a neoplasm affecting the chiasm itself.