It's not nice is it? I've had a few patients with it but , fortunately, not me. Sadly it may recur especially if you are a bit run down but at least you'll know and be able to get help. Frequent fliers at the eye depts usually know when it's coming before the signs really show so will be given their prescriptions on their own say so.
I can't say I have seen any links to covid mind, nothing mainstream.