I don't know what this eyesight problem is?

So for about half a year now, I have began to see sort of 'outlines' of objects when I look at them. I will try very hard to explain this to you, but I don't really know how.

So what happens is, whenever I look at something, I can usually see some sort of slightly see-through bit of it above or below. It gets more apparent (and less transparent) when the object is brighter, for example on a computer screen, or if I get further away from it, it gets even more visible.

It is causing me to not be able to read signs from a long distance away, so I am wondering if it is just a thing which happens when you are becoming near-sighted. I could describe the effect as making the text, or object, go blurry, which I have also heard is what happens when your vision is getting bad.

I also don't know if everyone experiences it, but I think they do. If you are ever looking at something bright in the dark, the light seems to cover up more of your eyesight somehow, if you know what I mean.

Could this just be because of some small issues that I have caused? For example, I tend to be looking at screens and computer monitors a lot, and I have quite a bit of sugar, but not a lot of exercise, and apparently sugar can cause your vision to go blurry like this.

I am slightly worried that this could be a bigger issue than just bad eyesight, like a serious disease, but I understand if you don't understand what I am trying to explain, because I don't know if anyone else has had this happen before.

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