Severely growth restricted kitten with glaucoma - Any ideas?

My kitten is now 7mths old and weighs 600g
She had severe diarrhea and a prolapse rectum from week 10 to week 16 or so.
Vets wanted to put her down and refused to test.

With ProKolin (bought online after advice, vet was useless) and boiled chicken broth she turned it around and seemed to bounce back. Started to put on weight, from her measly 375g.
 

2 weeks ago I noticed a shadow on her eye in photos. I emailed them to an ophthalmologist vet, in a different clinic to my usual (lost faith) and was advised to bring her in. Overnight her eyes swelled.

Was told she had glaucoma, cateracts and was 100% blind, with severe pressure in the eyes. However, the pressure reduced again and had a good week waiting on blood test results.
Was told it was probably FIP.

Good news, she passed all the blood tests, no FIP and everything else they tested for (still awaiting toxoplasmosis)
they kept her in overnight last night to trial some eye drops but today they are still none the wiser.

Does anyone have any idea what could cause these issues?

Shes a happy playful kitten, who you'd swear isn't blind... Shes got a great appetite, and although she is very cuddly and lazy a lot of the time, she does play when she wants to and winds up big Drew.

The vets are thinking of putting her to sleep, which I refuse to allow and will fight all the way. We've got through so much.
 

Toxoplasmosis and histoplasmosis can definitely effect the eyes of a cat.  Toxoplasmosis can manifest in the manner that you are describing with your cat.  Both of these infections are harder to treat when they are located in the eyes because of the different membranes involved.  If the test comes back negative then there might be nothing that you can do.  If she's happy and healthy, there's no need to put her down.  I would definitely suggest finding another vet if at all possible.

I just have to ask...you are feeding her MORE than just the ProKolin and boiled chicken broth, right?  That is not a balanced diet for a growling kitten and/or adult cat.  As far as I can tell, it's a fine probiotic, but you still need to feed a 100% nutritionally complete diet, which chicken broth is not. 

At this point, other than possibly an insufficient diet, I don't know what it might be, but I'd definitely wait for all the test results

She was on a complete kitten food until she got sick. I was advised it was an allergy and to try formula, chicken and rice, then scrambled egg as nothing was stopping the chronic diarrhea. Then I boiled chicken legs for over 3 hours and fed her that, minus bones, mushed and very fluidy to help her. Lots of fats and nutrition in this.
She finally got over the diarrhea and began to put on weight. Once her prolapse healed we slowly moved back onto a good quality kitten food.
She may well have been malnourished but that would be due to her illness not my care. She was close to death a few times but I stayed up all night with her feeding tiny amounts of formula with a syringe.
If you have any other ideas please tell me?? What would you do if everything other than the chicken broth that saved her life made her sicker?

Have you gotten the results of the toxoplasmosis test yet? 

What has the Animal Opthamologist told you?  Does it seem she has regained any sight?  Does she seem to be in pain?  Glaucoma can be painful because of the swelling of the eyes.  Have they made any recommendations (other than putting her to sleep)? 

Toxo is clear, titres under 50
Shes on Travatan for her eyes.
Shes in pain when they swell but seems under control atm

They won't do any more testing as she gets too stressed, they struggle to get blood/vein  and shes too small for the MRI

Does she have sneezing or discharge at all? The vet should have put her on meds to lower the pressure in her eyes otherwise the vision will not come back. Glaucoma is more of a symptom of an issue than an actual issue itself. Feline Herpes can cause swelling in the eyes, among other things..