In-universe, Geordi's VISOR causes him constant pain.

From ["Encounter at Farpoint"][1]:

> LAFORGE: Is a remarkable piece of bio-electronic engineering by which I quote see much of the EM spectrum ranging from simple heat and infrared through radio waves et cetera, et cetera, and forgive me if I've said and listened to this a thousand times before.
>
> (Without the Visor, Geordi La Forge's eyes are white sightless orbs, and he has flashing red lights at his temples)
>
> CRUSHER: You've been blind all your life?
>
> LAFORGE: I was born this way.
>
> **CRUSHER: And you've felt pain all the years that you've used this?**
>
> **LAFORGE: They say it's because I use my natural sensors in different ways.**

So as soon as an alternative was possible, Geordi would have a strong reason to switch as soon as possible.

Geordi had been offered some means of eliminating the pain, but they are risky and/or would interfere with vision. From the same episode:

> CRUSHER: Well, I see two choices. The first is **painkillers**.
>
> LAFORGE: Which would affect how this works. No. Choice number two?
>
> CRUSHER: **Exploratory surgery**. Desensitise the brain areas troubling you.
>
> LAFORGE: Same difference. No, thank you, Doctor.
>
> CRUSHER: I understand.


  [1]: http://www.chakoteya.net/NextGen/101.htm