i have worn contacts regularly since age 14 (i'm 31) and have never been able to do any sport with glasses w/o difficulty (i.e. perephial vision, distorted distance, sweating, etc)

i have had almost no problems using contacts for cycling - about the only problem is that it increases dryness of eyes - i try to wear covering sunglasses with mine to block the air at high speed -- then if they get dirty or i sweat too much or whatever i can take them off and still see!

there are lots of varieties (the first three are 'soft' lenses):
* disposable soft- any where from 1 day to 2 weeks and then throw away - great b/c they are easy and you don't have to worry about loosing them - disadvantage: only come in basic strengths/sizes so if often out of luck you need something special like heavy astigmatism or bifocal
* 'daily wear' soft - normal lenses you take out and clean every night - cheap, but often a pain if you wear them a lot
* extended wear soft gas permeable - so you wear for a few days up to a few weeks and then clean and re-use ---- ok, except can be expensive and then bad to worry about loosing - a hassle to keep clean
* 'hard' lenses - the original contact lenses that are smaller and harder and less comfortable but only choice for many people who cannot wear soft lenses or need a REALLY strong lense (like -7 or greater)

if you don't wear them too long then disposables are actually safer for the eyes i think -- of course there is debate as to how long 'too long' is - i.e. 2 days or 2 weeks ---- in college i often wore mine 15-20 days at a time and twice got eye infections - now i don't wear them so long and have no problems

i recommend disposable (i wear ACUVUE) b/c they're easy and comfortable - a box of 3 pair retails for about $25 so your cost depends on how often you wear them. if you wear glasses most of the time they can be quite affordable -- i suggest mail order if you already have a persciption which i assume if you have glasses