Need advice on kitten's eye.?

Eye crusties are not a "natural part of growing up" for kittens. It is either a viral infection or a bacterial one. Kittens are born with weak immune systems, and sometimes as they grow their immune systems can kick the virus or bacteria, but many times they cannot. Eye infections in kittens can be very serious - they can lead to scarring of the eye surface, vision loss, or even rupture of they eye. It's not something to just take lightly. If it continues or becomes discolored with green or yellow, then it absolutely must be treated by the vet. The person who is suggesting using tea bags to treat it has never seen a kitten with a thick white scarring over their eye surface, or with an eye that has ruptured from an untreated infection. There is no substitute for vet care, and nothing over the counter that you can get. Consider taking mom and the kittens to a no-kill shelter. They will spay mom and give the kittens the antibiotic ointment they probably need. This will most likely pass on to all of the kittens. In the worst case scenario, it's a symptom of an FeLV infection in the kittens, passed on from Mom. Mom and the babies are going to need to be dewormed - and this is something you cannot do with OTC products either. It's great that you took in Mom but she and the babies need care that only a vet can provide.

A lot of cats get this when they're kittens, it's a completely natural part of their growing up - it's not to do with an infection usually - although if it seems to be irritating the eye it could be. They'll probably keep reappearing, but theres nothing really to be dont about that I'm afraid ):

The best thing to do is set aside some used DAMP tea bags until they have gone COLD (if they dry too much then add a bit of cold water and squeeze them out so they don't drip). It is important that they are used because otherwise they will be too strong. Likewise don't use a highly perfumed tea bag like Twinings - the 'plainer' the better!

Get a very soft facial tissue to remove the 'crust' first and use the tea bags to gently rub your cat's eyes and the area around them with the cold damp tea bags and then throw them away. Make sure you use a separate tea bag for each eye to prevent infections.

There's no need to dry it yourself as the kitten will probably wash him/herself and this also allows the tea bags to take effect.

The reason this works is because tea contains an ingredient called tannin - it it commonly said that this is really good for the eye's health in mammals (humans, cats, dogs, rabbits, guinea-pigs, etc.) and is often a treatment used in health-spas. This is also much cheaper than buying products from Pet Shops/Vets.

Most likely it needs antibiotics nothing over the counter will work.