intermittent blindness in our cat

Question
Our cat went from 12 pounds to 9 pounds during the summer of 2006 (before the poisoning scare).  She was treated for parasites to no avail.  Subsequent tests showed her urea, creatinine & liver enzymes were more than slightly elevated.  Thyroid, glucose and CBC were normal. In November 2006 we noticed odd behaviour and white, cloudy eyes. We observed her closely and realized she was completely blind.  This stage lasted just over 2 weeks.  In the year since then she remains very under weight, sometime active, sometimes lethargic and has stopped grooming.  A few episodes of vomiting now -- her first decade with us she had never done this. Appetite comes and goes.

QUESTION --- Her eye sight is quite variable ! ?  We note her behaviour goes back to quiet and she walks close to doorways & furniture -- sure enough, her eyes are cloudy again.  Some days her eyes are very clear and it's obvious she can see well.  This cat is loved/spoiled with 4 caregivers offering her treats out of hand in addition to her food and water bowls.  On days her eyes are cloudy, we note it appears as if she finds it difficult to locate a treat we've offered --almost as if her sense of smell is also poor.  We don't know if her smell sense is always poor because on good sight days her behaviour suggests she "sites" the treats.

What could cause intermittent blindness ?  Could she have CRF despite her illness onset 5 months before the poison news broke ?  She is a "common" tri-colour tabby, currently 14 years of age.  If she had hypertension associated to CRF, would she have cloudy whitish eyes some days and not others ?

Answer
Thank you for writing.  You mention the poison scare, by which I am imagining you are referring to is the food that was found to be tainted.  CRF occurs in cats very frequently without external poisons. Since she was already found to have abnormal urea and creatinine readings it is definitely possible she is affected by CRF.  Single time elevated readings do not guarantee it though, if she has not been tested since 2006 I would recommend taking her in to have her evaluated.

The elevated blood pressure associated with CRF can lead to glaucoma, which can manifest itself as cloudy eyes and loss of vision such as you have seen in your cat.  The glaucoma if left untreated will lead to permanent blindness, so it would be best for you to have her examined by your veterinarian.  If this is found to be present they can help you to implement a treatment plan.

Best of luck to you and your feline friend.