There may be other health issues affecting your cat such as feline diabetes for example. High blood pressure can affect vision as can diabetes and result in blindness. Baytril, an antibiotic often given for feline urinary tract issues can affect vision as well.
If you are able to post your cats complete blood and urine results as well as dosages and current meds I am glad to review and offer you my specific suggestions
Dr Carol Osborne, DVM
Hello, just to let you know that Coco went to sleep today after taking a downward turn over the last few days. Thankyou for trying to help us. Kind regards, Julie.
Thanks very much for your offer I will speak to the vet and get all his results etc for your opinion. He is very thin and does not keep weight on despite contantly being fed / eating a lot, and I wonderered about his thyroid but the vet does not think his thyroid result is 'too bad' and has not put him on any treatment. He also has a fast heart rate. His weight loss has been over the last 3 years. He tends to normally sleep alot, and is slow on his feet due to the arthritis. His only meds are fortekor 2.5 mg once a day for his renal failure, amlodipine 1.75 mg a day for his blood pressure, and Ipakitine powder on his food (approx 0.5 g). Thanks very much for your help and advice.