Loss of vision sometimes occurs for the same reasons that cause weakness of vision, when these reasons are extremely strong. See the appropriate place for this. However, we will talk about this again and omit only what concerns the complicity of the brain and other things, because this is already understood there. Loss of vision may occur while the substance of the outer parts of the eye remains intact, or it may occur after dangerous damage has been done, that is, damage causing moisture to leak out and the like.
Let us now talk about the first type, namely the case when the substance of the parts of the eye is unharmed from the outside, but, on the other hand, it has suffered damage, which is usually invisible to people. In this case, visually the hole will be either in a healthy state or not. When the optic opening is healthy, then there is a cataract blockage there, or the blockage is not there, but in the hollow nerve and is either because something has got into its passage, or the passage has closed due to drying, relaxation or swelling in the hollow nerve, or in his muscles, which presses on the nerve, or he suffers from a compression occurring in the front part of the brain, as we have explained before, or the hollow nerve is ruptured, or the icy moisture moves away from its place opposite the optic opening, or a disorder of her nature occurs , so that it is no longer suitable for an instrument of vision. This often happens as a result of a strong predominance of humidity, or it happens from a predominance of dryness, from which the icy moisture wrinkles and shrinks. This disease is called glaucoma, and there is no cure for it. As a result, the eye becomes sunken and its color turns gray. As for the unhealthy state of the optic aperture, its expansion reaches the highest degree, and its narrowing reaches complete closure.
Signs. The signs of cataracts, dilation and narrowing of the optic foramen, and the like, have already been explained, each in its place.
As for the case when the loss of vision occurred due to the hollow nerve, it is easy to establish by the signs outlined in the paragraph on cataracts. However, an exact definition of the state is difficult and generally hardly comprehensible. If there is a painful beating and redness, then consider that there is a hot tumor in the hollow nerve, but if there is heaviness and little warmth, then consider that there is a cold tumor in it. If the heaviness is very noticeable and the eye is very wet, then the matter is wet. If the eye is dry, then the matter is dry and black-billed. If there is a blow to the head or a fall occurs, so that the eye first protrudes forward and then sinks, and vision is lost, then consider that the hollow nerve has ruptured.