If you wear glasses or sunglasses, choose either an open face helmet or a full face helmet that has a large eyeport and interior that works well with glasses. Some of the helmets to consider would be the following...
The Pyrotect Open Face Helmet is one of the best bang-for-the-buck open face helmets on the market. It features a lightweight fiberglass shell, a removeable & washable air-flow liner, interchangeable cheek pads, and is Snell SA2015 rated. Available in white, black, or flat black.
The Simpson Voyager Helmet features a lightweight fiberglass shell, a large eyeport, and removable cheek pads. The helmet is Snell SA2010 rated and available in gloss white or gloss black.