Your mom is quite right about that. It seems that a cold or sore throat has nothing to do with eye problems. But your nasal passage and your eyes are connected by your sinuses, so when your nasal passage is negatively affected, your eyes are affected by bacterial that will do harm to your optic neuritis. Your eyes may get weepy, blurry and irritating. It can even get pretty ugly, optic atrophy. Common virus infection, such as measles, mumps, flu, appendicitis and diarrhea can also trigger optic neuritis. Everything in our head is interconnected, so a petty cold might seem trivial, yet it can cause a real trouble to your vision. Do take some precautions regarding this nasty cold.
In many people's minds, it seems a little bit hard to connect having a cold to affecting their vision. Actually, it is true that common colds, to a very large extent, have a bad influence on your eyes, mainly because not only can cold germs easily enter our eyes, but the viruses can infect any kinds of cells as well. Consequently, individuals would suffer from the comfortableness and blear-eyed problem. What's worse, having a cold may give rise to neuratrophy related to vision. Therefore, it is very vital to pay much more attention if you have a cold, because various virus infection may cause optic nerve inflammation.
Of course having a cold will affect the eyes. There's a small channel to connect through your eyes and nasal cavity, it is canalis nasolacrimalis. The pharyngitis caused by cold will lead to the inflammation of canalis nasolacrimalis, once it and the blood capillary around it get blocked and swollen, the secretions of eyes can not easily released out, the eyes will turn to red and swollen. So please avoid worsening cold and drink more water, relaxi and keep a calm heart and it will get well later.
What your mom has said is right. The virus of cold pharyngalgia infects optic neuritis which may cause the eyes vision blurred. Thus, you will feel a little pain in the rear of the eyeball. Even in some bad situation, the optic may atrophy. The optic neuritis may be caused by some general virus infection, such as measles, mumps, influenza and appendicitis. Besides these, there must be other unreasonable effects that may cause the optic neuritis.