Hmm. I feel for Harrow.
I too had a similar problem. Sounds like it could be a mild infection; most likely a case of kitty conjunctivitis. If there is gunk or fluid weeping out of the eyes it is likely to be the conjunctivitis. If the eyelid is inflamed, it is probably infected too.
The treatment is both easy and difficult. The easy part is going to a vet, getting some cheap eye drops and watching them effortlessly administering the drops.
The difficult bit is that the treatment needs to be administered for up to a week at home, a couple of times a day. Us cats don't like eye drops.