I went to the vet today with Jessie and, Karlin and Sandy, you were right, it is corneal dystrophy. I am relieved, he told me not to worry, it is not an immediate or serious problem. Thank you for your advice, I'm delighted to have found this site. I have a disability and I am at home most of the time, Jessie is with me all the time and means the world to me.
She has a little cyst as well, but vet said that unless she was under anaesthetic, he wouldn't remove it.
All the best,