Eye Was There is created specifically for any person who is considering having an eye surgically removed or is coping with the loss of an eye. It is also created for that person's caretakers, family members and friends. There are limited sources of information, outside of a doctor's office, from which a patient can learn about what to expect before, during, and after the surgery to remove an eye. The doctor or the doctor's staff might not have the time to handle the variety of questions that are commonly asked. Many of the questions arise after the patient has left the doctor's office. Eye Was There is intended to serve as a source of information regarding the preoperative, surgical and postoperative options surrounding the loss of an eye. It explains the most common surgical procedures performed to remove an eye and the potential complications that can occur after surgery. It details some of the medical conditions leading up to the removal of an eye. It describes the emotional and psychological steps that are experienced when dealing with the loss of an eye. It contains historic and current information on the manufacturing and fabrication of artificial eyes and orbital prostheses. It provides instruction and advice regarding the care and handling of the artificial eyes and orbital prostheses that are worn after surgery. The book is meant to give a positive perspective of dealing with life after the loss of an eye.
Eye Was There
A Patient's Guide to Coping with the Loss of an EyeBy Charles B. Slonim Amy Z. MartinoAuthorHouse
Copyright © 2011 Charles B. Slonim, M.D. & Amy Z. Martino, M.D.
All right reserved.ISBN: 978-1-4567-6663-4 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
Anatomy
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 constant balance so that the pressure inside the eye remains fairly constant. If the drainage system becomes defective, then the pressure in the eye will go up. The condition where the pressure in the eye is too high is called glaucoma. If the pressure in the eye remains too high for too long, then damage will occur to the optic nerve. Damage to the optic nerve initially causes peripheral (side) vision loss, which can eventually lead to central vision loss and blindness. The optic nerve has approximately 1.6 million nerve fibers that go to the brain. Modern surgical techniques have not been developed yet to repair a damaged optic nerve; it is mainly for this reason that total eye transplants are not yet possible.
Behind the ciliary body is the choroid, which is made of many blood vessels. The choroid is sandwiched between the sclera of the outer layer and the retina of the inner layer. The choroid brings nourishment to both of these layers. Behind the iris and pupil lies the clear crystalline lens of the eye. Like the lens of a camera, the natural crystalline lens of the eye is responsible for receiving the light that enters the eye and focusing that light onto the retina in the back of the eye. Over time, the crystalline lens can become cloudy or opaque. When this occurs, the cloudy lens is referred to as a cataract.
The retina is a transparent tissue that lines the surface of the back of the eye and is in front of the choroid. The retina contains the photoreceptor cells known as the rods and cones. Photoreceptor cells receive the light which has been focused by the lens and changes the light into an electrical impulse. This electrical impulse is then transmitted through the optic nerve to the occipital lobe of the brain, where it is translated into a visual image.
There are two fluids inside the eye: the aqueous fluid and the vitreous gel. The aqueous fluid fills the anterior chamber, which is the space between the iris and the cornea. The vitreous gel fills the space inside the back of the eye behind the lens and in front of the retina
Chapter Two
Epidemiology The number of surgeries to remove an eye for medical reasons has declined over time due to earlier detection of diseases and more conservative management. The choice of surgical procedure to remove an eye has also changed over time. Initially, doctors were performing mostly enucleations, in which the entire eyeball and some of the nerve that connected it to the brain were removed. However, over the last few decades, many doctors are shifting to an alternative surgery called an evisceration, which involves removing just the inner contents of the eyeball. This way, the outer shell of the eye (the sclera) remains with all of its muscles attached, so that it may look and move more like the other eye.
Losing an eye does not discriminate based on age, gender, socioeconomic status, or lifestyle. However, young males of lower socioeconomic status experience ocular trauma and subsequent loss of an eye more than any other group. The number of eyes removed in each country around the world varies annually just as much as the reasons for removing them. Here in the United States, trauma is the most common event that results in the loss of an eye. The U.S. National Center for Health Statistics' Health Interview Survey estimates that around 2.4 million eye injuries occur in the U.S. each year. Another study has shown that approximately 3 people out of every 100,000 suffer a penetrating eye injury every year. As a result of these eye injuries, 50,000 people permanently lose part or all of their vision. Ninety percent of all eye injuries can be prevented by using protective eyewear. In a study involving 2,276 patients who were hospitalized as a result of eye injuries, 2,416 eyes were injured (140 patients injured both eyes). Forty-seven percent (1,070 patients) were children, who often sustained the most severe injuries. The male-to-female ratio was 4.3 to 1. Most patients retained good vision, 3.7 percent (89 eyes) lost vision totally, and 2 percent (48 eyes) had to be removed. According to the Society for the Prevention of Blindness, between 10,000 and 12,000 people per year lose an eye. Approximately 50 percent or more of these eyes are lost due to an accident.
Whether due to a motor vehicle accident, assault during an altercation, work-related injury, or even gunshot wound, patients who lose an eye due to trauma tend to be young males under age thirty. Work-related injuries often result from hammering nails; either the entire nail flies up and punctures the eye, or a piece of metal breaks off of the nail and hits the eye. Eye injury is a significant health problem in the United States, second only to cataract as a cause of visual impairment.
If the eyeball is punctured or deflated from the trauma, it is termed an open-globe (see: Surgery: Timing: Open globe injury). Around two hundred thousand open-globe injuries occur worldwide each year. Other common reasons for removing an eye in adults not related to trauma include cancer of the eye, especially melanoma; severe infection inside the eye, called endophthalmitis; and a blind eye that later becomes too painful to manage with medication or surgery. In children, many devastating eye injuries are due to preventable causes such as BB guns, paintball guns, and ice hockey.
Many of the eyes removed from children that are not due to accidents are the result of a cancer called retinoblastoma. Pediatricians examine the eyes of all newborns at birth and at every subsequent checkup after that to detect this uncommon, although devastating, childhood cancer of the eye as early as possible. If the cancer is detected early enough, medications may be used for treatment; this is referred to as chemotherapy. However if the retinoblastoma tumor is advanced, surgery to remove the eye is often the best form of treatment to prevent it from spreading to other parts of the body.
Worldwide, especially in third-world countries, serious eye conditions that result in the removal of an eye include infections and tumors. Delayed diagnosis and treatment, as well as little or no access to eye care specialists, likely explain much of this phenomenon. Although the number of enucleations may parallel that in the United States, there are more exenterations performed abroad. An exenteration involves removing the entire eyeball plus some of the surrounding tissues (such as muscle, fat, and possibly bone). For example, those living in a tropical climate in underdeveloped countries have a higher incidence of squamous cell carcinoma, a cancer that begins on the eyelids or surface of the eye and that can spread to surrounding bone. By the time that person seeks medical attention, the cancer may have spread very widely inside the orbit. The only option for treatment and a possible cure with widespread orbital tumors is an exenteration.
Chapter Three
Causes There are a variety of reasons (e.g., medical and surgical indications) that may prompt a surgeon to suggest that an eye may need to be removed. A number of factors must be taken into consideration before proceeding with surgery. These factors include the level of vision, the level of pain and discomfort, the risk to the good eye, the risk to the patient's general health in the case of a malignant tumor, the physical appearance of the eye, and the quality of life.
Probably the most important considered factor is the level of vision that exists in the eye in question. Visual acuity is the measure of the ability of the eye to see certain images of different sizes and shapes at different distances. Typically, this is determined by having a patient read an eye chart with multiple lines of letters or numbers that get progressively smaller as one reads further down the chart. The written or documented notation of a visual acuity is indicated in the form of a fraction (e.g., 20/40), which refers to distances measured in feet. This fraction is referred to as a Snellen notation of vision named after the Dutch ophthalmologist, Herman Snellen, who developed the chart in 1862.
The numerator (top number) indicates at what distance the patient must stand from the chart in order to be able to see a certain sized letter, number or shape. The standard distance for viewing the eye chart in the eye doctor's office is calibrated (mirrored) to a twenty-foot length. Therefore the numerator is usually indicated as 20. This means that the patient was able to see the identified letter at 20 feet. Outside the United States where the metric system of measurements is used, this is calibrated to 6 meters, which equals 19.69 feet. Therefore a visual acuity metric notation of 6/12 would be equivalent to 20/40. The denominator (the bottom number) is the distance that a population of persons with normal vision could see the same-sized letter on the same line of the eye chart. For example, suppose a patient can only see down to the 20/40 line on the eye chart. The size of letter or image that this patient can see at twenty feet can be seen by persons with normal vision at forty feet away, or twice the distance.
The definition of legal blindness differs around the world. In the United States, the definition of legal blindness is defined as a visual acuity in the better eye with the best possible prescribed glasses of 20/200 (the biggest "E" on the chart) or worse, or the peripheral field of vision (side vision) restricted to twenty degrees or less in the better eye (tunnel vision).
When the letters on the eye chart can no longer be seen because of poor or deteriorating vision, then the eye doctors refers to a different nonnumerical (i.e., non-Snellen) system of indicating a visual acuity (e.g., NLP, LP, HM, CF). Being able to count fingers held in front of the patient within a few feet of their eye is referred to as count fingers (CF) vision at, for example, two feet. If the patient cannot delineate the number of fingers held up by the eye doctor, they will be asked if they can see hand movement. The doctor will wave his or her hand in front of the patient's face. If the patient can see the movement of the hand, this is referred to as hand motions (HM) vision. If hand motions are not visible to the patient, the eye doctor will ask the patient if they can see a bright light source shined into their eye. If the light is visible, this is referred to as light perception (LP) vision. If the patient can tell from which direction the point source of light is coming from, then this is referred to a "light perception with projection" vision. If no light perception is seen by the patient to the brightest available beam of light, then this is referred to as no light perception (NLP) vision. A no light perception eye is considered to be a totally blind eye. It is at the NLP level of vision that an ophthalmologist will consider removing an eye depending on the circumstances surrounding the medical necessity to remove that eye.
Birth Defects
There are occasions when infants are born with birth defects that directly affect the eye. Three such conditions are microphthalmos, congenital cystic eye, and rarely, anophthalmos. Microphthalmos is a condition where the eye is extremely small and blind. A rare condition called congenital anophthalmos is where the infant is born without an eye in the socket. The term "socket" refers to the space contained within the orbital bones that contains the eyeball. The socket surrounds and protects the eye.
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Excerpted from Eye Was Thereby Charles B. Slonim Amy Z. Martino Copyright © 2011 by Charles B. Slonim, M.D. & Amy Z. Martino, M.D.. Excerpted by permission of AuthorHouse. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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