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Eye Was There

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Contents

Dedication......................................................vAcknowledgement.................................................viiIntroduction....................................................xiAnatomy.........................................................1Anatomy of the Orbit............................................1Anatomy of the Eye..............................................2Epidemiology....................................................5Causes..........................................................8Birth Defects...................................................10Blind and Painful...............................................10Painful and Unsightly but Not Totally Blind.....................11Trauma..........................................................12Intraocular Tumors..............................................12Cosmetic........................................................13Psychology of Organ Loss........................................14Cosmesis without Surgery........................................17Scleral Shell...................................................17Cosmetic Contact Lens...........................................18Surgery.........................................................19Timing..........................................................19Blind and Painful Eye...........................................19Open-globe Injury...............................................20Sympathetic Ophthalmia..........................................21Procedures (The 3 Es)...........................................23Enucleation.....................................................23Evisceration....................................................31Exenteration....................................................33Complications of Surgery........................................36Intraoperative..................................................36Early Postoperative.............................................37Late Postoperative..............................................40Socket Reconstruction...........................................45Pediatric Anophthalmos..........................................49Socket Development..............................................49Pediatric Surgery...............................................50Prosthesis......................................................51History.........................................................51Ocularist.......................................................52Anaplastologist.................................................53Manufacturing an Ocular Prosthesis..............................54Manufacturing an Orbital Prosthesis.............................55Care and Handling of an Ocular Prosthesis.......................57Care and Handling of an Orbital Prosthesis......................61Life with a Prosthesis..........................................63Physical Limitations............................................63Occupational Hazards............................................63Protecting the Good Eye.........................................64Glossary of Terminology.........................................67

Chapter One

An understanding of the basic anatomy of the orbit and the eye is necessary to appreciate the relationships between the parts of the eye and orbit that are surgically removed and the parts that are left behind and eventually support the artificial eye (i.e., the prosthesis). For the purpose of this chapter, the eye socket will be divided into two sections: the orbit and the eye.

Anatomy of the Orbit

The orbit is a recessed bony cavity in the face positioned on either side of the nose. Each orbit contains a number of soft tissues and structures including the eyeball, muscles, nerves, blood vessels, fat, and fascia. Each orbit is shaped like a pear, with the top of the pear pointing toward the back of the head. Each orbit has four main inside surfaces or walls, which are described by their relative position in each orbit. There is a "roof" on the top and a "floor" on the bottom of each orbit. There is a medial wall (closest to the nose) and a lateral wall (closest to the ear). There are a total of seven different bones that make up each orbit. Some of the bones have holes in them to allow the passage of nerves and blood vessels. The opening edge of the orbit crates a round shape and is called the orbital rim.

The orbit also contains six extraocular muscles that are attached to the outside surface of the eyeball called the sclera (the white part of the eye). These muscles are responsible for eye movements. The eyeball is actually positioned in the center of these muscles. The optic nerve extends from the back of the eyeball through the center of the muscles; it continues through the back of the orbit and goes through a hole in the back of the orbit and connects with the brain. Surrounding the extraocular muscles, the optic nerve, and the eyeball is the orbital fat, which helps to support and cushion the eye in the orbit. The lacrimal gland, which produces watery tears, is positioned in the upper and outer portion of each orbit. The lacrimal drainage system, which helps drain the tears away from the eye, is located in the lower and inner portion of each orbit. Positioned in front of the orbital rims are the eyelids.

Anatomy of the Eye

The eye is a very complex organ that is made up of many parts. Each part has a specific function, and together these parts are responsible for creating a visual image which is interpreted as vision.

There are three main layers of the eyeball. The outer layer is a protective layer made of a very tough, fibrous tissue. In the front of the eye this tissue is a clear dome, called the cornea, and it represents about 20 percent of the entire surface of the outer layer. A healthy cornea has no blood vessels in it; it is the only part of the eye that can be transplanted. When a cornea becomes cloudy due to disease or trauma, a surgeon can replace the central portion of the damaged cornea with a clear cornea that has been donated from a deceased organ donor; this is called a corneal transplant. The other 80 percent of the outer layer is white and is called the sclera. Attached to the sclera are the six extraocular muscles, which are responsible for all of the eye movements.

The middle layer of the eye contains extremely delicate structures that include the iris, ciliary body, and choroid. The iris is the colored portion of the eye that gives someone the appearance of having blue, green or brown eyes. In the center of the iris is the pupil which is the black circular hole that allows the light to go through to the back of the eye. The pupil regulates the amount of light that goes into the eye. The pupil opens widely in dark light and closes to a small hole in bright light.

The ciliary body produces the fluid (aqueous) that fills the eye and maintains a certain pressure needed to keep the eye in a round shape. Inside the front of the eye is an area between the back of the cornea and the front of the iris; this area is called the filtration angle, where the aqueous eventually drains from the eye. The production of aqueous from the ciliary body and the drainage of aqueous from the filtration angle must be kept in a...