* Glasses protect the eyes against the wind, sun glare, and small objects such as bugs, and sand and gravel kicked up by other riders or cars. Always use plastic lenses that cannot shatter on impact. I used to recommend Oakleys, and the glass is still very good, but the frames are cheap and break easily and it is impossible to buy replacements; they have some ridiculous mail-in policy. The often-repaired Oakleys I have now will be my last ones. (Note: with great satisfaction I have thrown them away now, and replaced them with $14.95 glasses from Performance. What an improvement!)
Cheap glasses are sometimes not be perfectly planar and distort light, or are not perfectly clear. This is very hard to judge in the shop because when they are new they are polished perfectly. Try to get some where you can attach different glasses to the same frame, you may need both gray shades and clear ones. I do not like orange or yellow ones; they are supposed to increase contrast but I have a hard time judging whether that is oil or water on the road in front of me. I now favor brownish gray ones; the brown color filters the bright blue sky somewhat.
Do not buy lenses coated with ceramics, like Alpina ones. True, they have no static electricity problems, but they scratch easily, are very hard to clean because they grab the cloth, and they become less clear with age.
If you wear prescription glasses, your options are limited. A reader, Graeme Dewar, reports thet Rudi Project Kerosene glasses (they have a number of other different models) allow prescription optical inserts to correct your vision. Other eye wear makers are marketing similar systems, including Adidas, Oakley and some other cheaper brands.
Summary
So, do the advantages justify the expense and peculiar look of specialized bicycle clothing? If you ride more than a couple of kilometers a day, and have a high-performance bicycle (as opposed to a gaspipe clunker), definitely. I find riding in regular street clothes uncomfortable, and even painful, and it would take away much of the fun of riding a bicycle. If you want to buy just a single piece to try it out, get padded shorts. It doesn't have to be Pearl Izumi, a $30 sale will do nicely as long as you get the right size.
A word about prices: I haven't found significant price differences for bicycle components in different European countries and the US, except that locally made components are sometimes (Specialized) but not always (Campagnolo) somewhat cheaper. Clothing is an exception, it seems that end-of-summer sales go down to half as much in the US than here in Germany. At standard retail prices though, at an approximate US$/Euro parity, the USA tend to be more expensive than Europe.
See also an article on "Riding in town"
