Seeking advice regarding Cocker Spaniel with Glaucoma.

Our little girl (Lucy), a Cocker Spaniel, has what appears to the vet to be glaucoma in both eyes. He gave us some eye-drops and the information of a specialist in a city nearby.

It's been about a month and a half and we finally started the process of scheduling an appointment. We have no idea how we are going to afford it especially since we already have an expensive care-credit account for a life-saving hospital visit for our cat this year.

Hindsight is 20/20 and I know a million things I would do differently to protect Lucy if I had a do-over, but what will my options be from here? What should I know before visiting the Veterinary Ophthalmologist?

I would be grateful for any advice you could provide. Thank you!