One big nuisance is fogged goggles. To help prevent this, a little spit rinsed out with water just before you put them on works a lot of the time. Otherwise, you may want to get anti-fog goggles or use anti-fog drops.
The most important factor is goggle fit, also known as not leaking. You will need to try out several different types. While at the pool, borrow different styles from other swimmers; tell them why before you ask and you should have no problem, since most of us swimmers are a friendly group.
A few things to consider:
- A press on fit - without using the strap do the goggles stay on your eyes for more than a split second?
- A comfortable fit - with adjusting, does the center piece (over the nose) feel right, without cutting your skin? Do they goggles feel good on your eyes with the strap? If they have foam, is it sufficient to both form a seal and cushion the sharp edges of the goggles?
- Good construction - do they look like they were put together (Swedish goggles excepted) with the proper amount of adhesive used on the foam?
- A proper tint - smoke or dark colored or mirrored goggles are good for bright areas, while clear or lightly colored are better for dim or indoor use.
- UV protection - will they safeguard your eyes when used outdoors? A strong strap - does it look durable and have the same elasticity as a strong rubber band?
- Extra features - do you need anti-fog, hypoallergenic, or prescription lenses?
- Optically safe lenses - are they shatter resistant?
- Cosmetic features - does the strap color or foam color what you want?
Kids Some goggles seem designed specifically for kids (or for that kid inside of adults). They usually feature a smaller diameter and have an easy to adjust strap. They may come in clear or in a tint for those bright days, and some even have decorative trim to look like lizards or fish. I would not recommend spending a lot of money on goggles for children, they seem to lose track of goggles all of the time, but do make sure that what they have work. Look for a strong strap, a nose piece that has little to no stretch to it, and if the goggles use a foam gasket, make sure it is glued on securely, with no gaps between the lens material and the foam.
As a coach, I can attest to both the frequency of lost goggles, and the "oops, I lost 'em" incidents due to the goggles just not working. I have a large collection of goggles, some good, some not, built up by the end of each season. Remember to mark the swimmer's name on the goggle strap - at least this increase the chances of getting them back if they did work.