One of our 12 week old kittens has developed a sticky eye. Some days I have to clean it a couple of times, then it can be clear for a few days before it happens again. Occasionally both eyes but usually just the one. It doesn't seen to bother her, the skin/ eyelid doesn't look red or swollen, she's not sneezing, she doesn't rub at it or anything- but I have noticed a couple of times that she'll keep that one eye shut for a few seconds. (Her brother's eyes are totally clear.) Do I need to worry? I don't want to stress her with a visit to the vets if it's likely to just be one of those things. I had cats as a child and I remember all of them had this at some point.