Start with your purpose (daily wear, driving, or sports) and pick a purple lens with adequate UV protection. Check frame size and comfort to ensure a good fit.

Key criteria are lens tint and polarization, UV protection, frame fit/size, and lens material. Consider price and brand as supporting factors.

For driving, polarization and glare control help; for sports, look for a secure, lightweight frame; for everyday wear, style and color coordination matter.

Driving in bright sun benefits from strong polarization and glare reduction; for all-day casual wear, prioritize comfort; for sports, seek a secure, lightweight frame.