Eyelid ptosis affects the muscles in the eyelid that are designed to lift the upper eyelid. It is most commonly caused by ageing but can also occur in younger adult patients who wear contact lenses. This is due to the continuous contact with the eye during insertion and removal of the lenses. Very occasionally, ptosis can be caused by neuromuscular disease. Eyelid ptosis can also occur with the use of some drugs, following eyelid trauma or as a by-product of an eyelid lump such as a large chalazion or tumour.

A full ophthalmic examination is performed to check visual function, eye movement, the eyelid condition and the ocular surface. A full face examination is performed where special eyelid measurements are taken and a phenylephrine test is performed to assess the degree and type of ptosis. This helps decide the specific surgery that may be required. The only permanent way to treat eyelid ptosis is with surgery. Occasionally, injection treatments or eye drops can be used to temporarily rectify minor upper eyelid ptosis.