Eyelid anatomy and physiology with reference to blepharoptosis

Abstract

The eyelids provide mechanical protection to the globe, produce chemical elements to the precorneal tear film, and help distribute these layers evenly over the surface of the eye. Eyelid motility requires a sophisticated interplay of muscles and suspensory systems that are intimately related to ocular movements, coordinated by fine sensory and motor control mechanisms. This chapter reviews anatomy and physiology of the eyelids and its suspensory system as a foundation for later chapters on evaluation and surgery for blepharoptosis repair. We also discuss the forces that determine eyelid position and complex blinking movements. These include those forces exerted by the levator and supratarsal muscles and the nature of their attachments, the anterior/posterior position of the eye, and the forces of gravity. Specific fiber types and their metabolic differences are important factors in understanding the function of the levator muscle, Müller's sympathetic muscle, and their relationship to extraocular and other skeletal muscles. © 2011 Springer Science+Business Media, LLC.