I have this DVD drive that is around 6 years old.

I noticed recently that when I put in dvd's it will play but it has a green pixelated screen sometimes.
If I play this same DVD in my other DVD drives, one 3 years old, one 1 year old DVD-burner, one laptop DVD burner (7 weeks old). It plays fine.

So I've covered a whole range of dvd drives, so I'm guessing the DVD drive is breaking.
I might move the 3 year old DVD drive to this computer soon as the other computer still has DVD playback via the DVD-burner.

It also works fine on my DVD player connected to the television.

Could it be because the lens is dirty or is the laser dying?
Oh and if I eject and put the DVD back into the drive, it suddenly works again...

However, if I do it a few more times, it doesn't work again.

Any ideas?
I'm pretty sure the laser is dying, I had a CD burner before and it just stopped burning properly.
However, this is a normal dvd playback drive...