What kind of diseases other than glaucoma and cataracts can cause blindness?

Many: The list is long and the answer also depends upon how you define blindness. There are inflammatory conditions of the eye which can lower vision. There are many inherited conditions that lower the vision and sometimes cause almost complete blindness. Macular degeneration causes visual loss. Diabetes and retinal detachments are others. I hope you don't have any of these.

Many, many: An entire medical specialty is devoted to identifying ocular and systemic diseases that are threats to vision. So, really too many to list. Ocular problems include macular degeneration, blood vessel obstruction, infection, injury, tumors, etc! systemic disease includes blood vessel obstruction, diabetes, tumors and on and on!

Blindness: Any disease of the eye that degrades the quality of the image transmitted to the brain can cause blindness. Therefore any diseases of the cornea, retina or optic nerve can lead to poor vision.