Eyelid Anatomy

On each side the eye socket (bony orbital cone) contains the eyeball, muscles that move the eye and the optic nerve, these are encased by orbital fat which protects the eyeball from the hard walls and holds it still within the orbit.  Holding these orbital contents in place is a dam like structure, the orbital septum, running from the bony orbital rim into the eyelid around the entire orbital rim of the socket. On top of the septum and immediately under the skin lies the obicularis oculi muscle which assists with eyelid closure.

Aesthetically pleasing eyes usually have the following anatomical features;

• No excessive skin forming hooding in the upper lid or wrinkles in the lower lid.
• A well defined upper eyelid fold with a rim of visible eyelid beneath it.
• No fat bulging behind the eyelid.
• The upper eyelid margin covers the upper coloured portion of the eye (the iris) by 1 – 2 mm.
• The white of the eye is not visible between the iris and the lower lid margin.
• The outer corner (lateral canthus) of the eye is 1-2 mm higher than the inner corner (medial canthus).
• Well maintained eyebrow height and shape.

With ageing the septum tends to weaken letting the orbital fat push forward to cause a bulge to appear in the eyelids.  With the passage of time both the eyelid skin and the underlying muscle become stretched and excessive, leading to upper lid hooding and lower lid wrinkles.  Descent of the brow exacerbates upper eyelid hooding.  Whilst cheek descent increases the apparent lower eyelid length and deepens the groove beneath the lower lid – the nasojugal groove.