Sunglasses or tinted lenses in brown, green, grey or other colours.
Lens tint covers a large part of the face, more than a frame colour alone.
Brown and grey tints tend to be the most versatile across different outfit colours.
The tint sits in front of the eyes rather than beside them, so this is more about the overall look than an echo effect.
Browse eye coloursBrown and green tints often coordinate with warm hair tones; grey tints read more neutral.
Browse hair coloursFrame material (metal vs plastic) usually matters more here than the lens tint itself. Compare metals.
A tinted lens is a filter: it transmits some wavelengths more than others, so everything seen through it — and the eyes seen through it by others — shifts towards its colour. Grey tints cut all wavelengths roughly evenly and so darken without much hue change; brown and amber tints absorb more of the blue end and so warm the view; green tints sit between the two. From the outside, a tinted lens also reflects the scene from its front surface, so how dark and how coloured it looks to others depends heavily on what it is facing.
The material: Tint can be dyed into the lens, applied as a coating, or combined with mirror coatings that reflect a different colour from the one they transmit — which is why a mirrored lens can look blue from outside yet warm from behind.