Goggles and facemasks

I use ESS ICE 2.4 glasses with an insert (might be the same one as fits in the Advancers).

Ditto

http://uktactical.com/acatalog/ESS_ICE_2.4.html
http://www.tactical-kit.co.uk/ess-vice-rx-prescription-insert-advancericeice-naro-3991-p.asp
Above links are not necessarily recommended sources but indicative of products/prices.
You will need prescription lenses fitted to the inserts. This is a military grade, quality solution to protect your eyes comfortably. The glasses themselves are a reasonable cost (you can also buy them easily on ebay) but the cost bumps up a lot with the inserts + prescription lenses.

Another solution some use is eye protection goggles from B&Q and the like - look for kitemarks and BSI standards. Check that there is enough room for you to wear your normal specs with them. General worker's eye protection glasses may comply with safety standards but do make sure they meet your cheeks - many an airsofter has been alarmed by a random BB entering from under the frame. Unlikely to cause eye damage but scary all the same.

Other solutions (which you can hunt down by a search on this forum) are wire mesh goggles painted to look like skin.

Whatever you get it is always worth blasting a BB at very close range as a test to give you peace of mind that they are up to the job. Note that frames don't have to meet safety standards and a well placed BB can break them - I've lost a couple of glasses that way.

On the subject of gaps: I've found that the inserts on mine fill in most of the gaps.

You'll probably need some kind of anti-fog treatment for the inserts, too. I've found that the inserts have a tendency to fog, but the main lens doesn't.

Also, if you're going to wear ordinary glasses under safety goggles, etc. make sure you have, or use, a spare pair of glasses just in case they get damaged.

+! for ESS, they're great.

Their anti-fog cloths are the best I've found too: http://www.polimil.co.uk/acatalog/ESS.html

ive always used bog standard clear saftey specs, ive only ever had one pair shatter, and that was some prick at shitefighter woodland using a hot minimi at 10 feet right accross the specs.

i had a pair crack in the middle at a ww2 airsoft game, but i think it was after id sat down on them.

i change them for a new pair every game anyway, every game a new, clean, scratch free pair for about 3 quid , (or free as i get them from work)

i also wear glasses normaly and im not vain but i use contact lenses for airsoft with mesh gogles painted to look more flesh colour,something to note is not to put it too bluntly but how sweaty are you.ive yet to find any clear plastic lenses(after 13 years of airsoft) that i cant fog up but i do suffer from hyperhydratiion meaning i sweat a lot,and there's nothing so anoying as finding you'r under fire and just cant see because you'v foged up.i dont like mesh because of the vision impairment but its the only solution and i really recomend daily diposable contact lenses,about £20 for 20 pairs and thats a year of airsoft for me