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It just looks like dried cleaning fluid to me as it is white. Someone else will be along shortly to correct or confirm. If you think something is wrong with your piggie then take her to the vet. A vet would rather see a well piggie who has an anxious owner than an ill piggie with an owner who has left it too long.
I agree - that is just a little eye cleaning fluid that has not gone down the tear duct. Nothing to worry about!
However, if you are in any doubt, please see a vet promptly in case it is gunk from an eye ulceration (blueish film over the eye), that is caused by an injury or something stuck under the eye - but as far as I can see, the eye is perfectly clear.
Crusts from a settled in URI are usually thick and yellowish or greenish, like dried thick snot and they can glue up the eye.
You may find this guide here helpful in learning what is normal and what not in a guinea pig body: Guinea pig body quirks