Sudden outbursts in behavior

Our 8 year old female Tabby cat has recently started having bursts of anxiety (I guess). Sometimes she'll be asleep on our laps and will jump up suddenly without cause like she's scared and tends to claw myself and my husband very badly trying to scurry away. It's happened quite a few times in the last few months and is only starting to occur more. I've noticed that when she has these outbursts all of her fur is sticking straight up and her eyes look dilated and sort of glazed over. Any advice on what it might be? There usually aren't any fast movements or sudden loud noises when it happens so I'm not sure what else causes it. The last time she did that her eyes were dilated for over 24 hours and she was extremely skiddish the whole time.