Congenital Nystagmus Question?

I haven't heard about any Nystagmus cases getting worse and usually it is not your Nystagmus that affects your vision but an underlying problem such as short/long sightedness, myopia etc. I went through a phase when I thought my sight was becoming worse but it turned out my eyesight had improved but the change although slight had made an impact in my vision for a few months until my brain got used to it