This is the most common cause of ptosis. The muscles that elevate the eye stretch and become thinned as we age, resulting in a loss of muscle tone and inability to raise the upper lid well.
Ptosis affects both eyes, but often one eye appears worse than the other.
Eye surgery, such as cataract removal, may aggravate this condition. Noticed at birth or shortly thereafter, congenital ptosis is produced by a developmental abnormality in the muscles that elevate the upper lid. Three-quarters of the time it affects only one eye. Automobile accidents often damage the delicate structures around and in the eye. Lacerations, burns, and chemical injuries may also cause this droopiness.