Why are ordinary glasses or sunglasses not sufficient for eye protection while riding?

Ordinary glasses or sunglasses do not provide adequate eye protection while riding primarily because they may not effectively seal out wind and dust. When riding a motorcycle, the high speeds can create strong winds that can irritate your eyes or lead to debris and dust entering your eyes, impairing your vision and compromising your safety. Specialized riding eyewear is designed to fit more snugly and securely, ensuring that wind and any foreign particles are minimized, allowing for better visibility and comfort while riding.

The other options touch on aspects of ordinary eyewear, such as the potential for scratching or issues with weight, but they do not address the critical need for sealing capabilities that protect the eyes in the dynamic conditions experienced when riding a motorcycle. Proper eyewear should enhance safety by providing a better barrier against external elements that can distract or harm a rider's vision.