Vision is often foggy

Compressive optic neuropathy, unilateral progressive and painless occult visual loss are the main clinical features. Vision is often foggy, and temporary darkening can occur immediately when looking at a certain location, due to direct compression of the optic nerve or blood vessels. Compressive optic neuropathy is caused by direct compression or invasion of intraorbital or intracranial tumors or metastatic cancer, which is sometimes misdiagnosed clinically and should be alert.