I have had more than one rescue animal missing an eye. It's not a death sentence.
After working at a vet clinic for many years, an eye ball HANGING from the animals face is indeed a death sentence (in most cases).
I realize this isn't a gecko, but my female pugs eye was dislocated and hanging out of her eye socket when she was around 4 months old. We rushed her to an emergency clinic and they easily removed the eye and she came home in a few days. She has adjusted to life with one eye and is now 6 years old. We were told this is a very common issue with pugs. I know this is about a gecko, but its not a death sentence to loose an eye. If it is taken to a vet (in this case if it was) there is, in my opinion, a chance the animal can be saved if the person was willing to pay for the surgery.