Microsurgical Techniques in Ophthalmology – Current Procedures and Future Directions

A thorough understanding of normal ocular anatomy is critical to define pathologic anatomic conditions, to delineate surgical goals, and to develop and utilize surgical tools to optimize patient outcomes. The anatomy of the eye and orbit can be broadly categorized as extraocular structures (including the eyelids, lacrimal gland, canalicular system, conjunctiva, and extraocular muscles) and intraocular structures, located within the globe of the eye. Intraocular structures are further grouped based on their location in the anterior or posterior segments of the eye (figure 1). The anterior segment consists of (from anterior to posterior): the cornea, anterior chamber, iris, and crystalline lens. The crystalline lens is suspended in place by hundreds of zonular fibers, which extend from the ciliary body to a thin capsule surrounding the lens. Contraction of the ciliary body changes the tension of the zonular fibers on the lens, allowing the lens to change its shape and focusing power. The cornea and lens are of particular importance as a majority of ophthalmic surgical interventions are performed on these structures, such as corneal transplantation, refractive corneal surgery, and cataract extraction.