What leads to progressive vision loss?

A long list: Any pathology of the eye can lead to progressive vision loss. If you are referring to permanent loss, then it could he inherited disease like retinitis pigmentosa, or retinal disease like macular degeneration. Most vision loss is correctable so if yours is fading, see your ophthalmologist

Vision loss: Vision loss can be due to many things: most common is need for new glasses. If still not correctable vision: can be due to cataracts, glaucoma, macular degeneration, blood vessel issues. Many other possibilities as welll: Brain lesions, medications, trauma, infection, cancer. Patient should be checked by eyeMD.