Old Dog's Red Eye That's Slow to Heal
A painful red eye after a possible injury is often a scratch or ulcer on the cornea, the clear front of the eye. Most simple scratches heal within 3 to 5 days, so it makes sense that your vet expected it to be better. Some ulcers are slow to heal, though. These "indolent" ulcers have a loose surface layer that won't stick down, and they can take weeks.
Slow-healing ulcers can happen in dogs of almost any breed, and they're usually treated by gently removing the loose surface cells, sometimes followed by a small procedure on the cornea, along with drops, pain relief and a protective cone. That's exactly what a veterinary ophthalmologist can do, so the appointment is a good step.
Corneal ulcers are very painful. Keep the cone on so she can't rub, and give her drops exactly as directed. Don't use any steroid eye drops unless your vet has confirmed the ulcer has healed. Call your vet before the appointment if the eye looks cloudier, the discharge increases, or she seems in more pain.
This is general information, not a diagnosis. Please follow your own vet's advice.