Compare the listed lens width, bridge, and arm length to a pair you already wear comfortably. Cat-eye and upswept shapes usually complement round, oval, and heart-shaped faces; square and rectangular Guess frames often balance softer features. If your face is narrower, avoid the most oversized silhouettes and stay closer to your current frame width. Use side-on and front-on product images to judge where the frame hits your brow line and cheekbones.