Ординатура / Офтальмология / Английские материалы / The Encyclopedia of Blindness and Vision Impairment_Sardegna, Shelly, Shelly, Steidl_2002

cancer Cancer of the eyes is relatively rare. According to the American Cancer Society, ocular cancer is responsible for approximately 2,500 new cases of cancer each year and for approximately 400 deaths from cancer each year as compared with lung and breast cancers, which are responsible, respectively, for 144,000 and 115,000 new cases of cancer each year.

Cancer of the eyes usually develops into tumors. The tumors may be found in the eyeball, the orbit, or the eyelids. Because ocular tumors are often hidden deep in the eye and therefore resist biopsy, it is often difÞcult to differentiate a malignant tumor from a nonmalignant or benign tumor.

Cancerous or malignant tumors differ from benign tumors in several ways. The cancerous cells are different from their surrounding tissue, often grow quickly and uncontrollably, rarely stop growing, and tend to spread or metastasize to other parts of the body. Malignant tumors threaten life as well as vision.

The three most common types of malignant tumors are malignant melanoma, retinoblastoma, and metastatic tumors. Each is a serious disorder that beneÞts from early and appropriate treatment.

MALIGNANT MELANOMA is the most common of all tumors that originate in the eye. This type of tumor grows from melanin-laden cells in the eyeÕs CHOROID, IRIS, or CILIARY BODY. It generally affects one eye only and may develop spontaneously or from a mole within the eye. It is usually slow to grow and metastasize. The onset may be at any age and is more common among whites than blacks. They occur more often in people who have skin melanoma.

Symptoms of malignant melanoma include redness, inßammation, loss of vision, and GLAUCOMA. Pupil distortion may be present in melanoma of the

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iris. Little is known about the cause and progression of these tumors.

Malignant melanomas are generally treated by enucleation, or removal of the entire eye. An uncertain diagnosis may lead to a period of observation augmented by chemotherapy or radiation treatments. Melanomas of the iris are extremely slow-growing and are often treated during observation. Approximately 60 percent of those diagnosed and treated for malignant melanomas are alive Þve years after treatment.

RETINOBLASTOMA is the most common type of malignant intraocular (inner eye) tumor in children. It occurs in one out of every 12Ð20,000 children. This tumor develops in the eyeÕs retina. Retinoblastomas may be hereditary or may develop sporadically. The less common hereditary type is usually present at birth and has its onset near one year of age. In both types, the condition is almost always expressed by age Þve. It is often bilateral (affects both eyes).

Although hereditary retinoblastomas are present in family histories, any occurrence of bilateral retinoblastoma should be considered hereditary and capable of being passed to further generations. Infants of hereditary families should be screened regularly for tumors.

Sporadic tumors are not hereditary. They are generally unilateral (affecting one eye only) and appear at approximately two years of age.

The Þrst symptoms of retinoblastoma include redness, pain, and inßammation. As the tumor grows, the eyes may cross and the pupil may change from black to white or gray, a condition called leukokoria. The light color is the hue of the tumor visible through the hole of the pupil.

Retinoblastoma is treated by enucleation, radiation, or cryotherapy (freezing treatments). In bilat-

eral cases, the more affected eye may be removed and the other eye may receive chemotherapy or radiation treatments. If left unchecked, the tumor could grow and spread up the optic nerve to the brain.

The cause of retinoblastoma is due to the absence of both retinoblastoma genes on the 13th chromosome. Although it has the one of the highest rates of spontaneous regression among all tumors, little is known about the cause of regression. The cure rate for retinoblastoma ranges from 85 percent to 90 percent.

Metastatic tumors are malignant tumors that originate in other parts of the body and spread to the eyes. Among those that can metastasize to the eyes are tumors of the lung, breast, kidney, and prostate. These secondary tumors are bilateral approximately 25 percent of the time.

Symptoms of metastatic tumors may include redness, pain, vision loss, or glaucoma. Often, symptoms of the ocular tumor may present themselves before those of the primary tumor. Because metastatic tumors look much like primary ocular tumors, diagnosis can be problematic.

Once a metastatic tumor has been diagnosed, the primary tumor can be appropriately treated. Depending on the size and growth rate of the ocular tumor, treatment may include surgery, chemotherapy, or radiation treatments.

Malignant tumors of the eyelids include the basal-cell carcinoma and the squamous-cell carcinoma. The more common basal-cell carcinoma, the result of sun damage to the skin, Þrst appears as a slight bump on the eyelid. It develops into a saucerlike shape with a raised edge.

Since the tumor is on the eyelid, it is easy to remove and submit to biopsy. If left untreated, the tumor may spread to the underlying bone. Advanced basal-cell carcinomas are treated with radiation therapy.

Squamous-cell carcinomas appear in observation much like basal-cell carcinomas but can be identiÞed through biopsy. This type of tumor tends to spread to the lymph nodes of the upper or lower eyelid and may metastasize to other parts of the body.

Rhabdomyosarcoma is a highly malignant tumor of the orbit. It is a rare tumor that develops

in children. The tumor spreads rapidly but can be detected by a biopsy taken through the eyelid. Treatment may include radiation or chemotherapy. Cure rates for rhabdomyosarcoma range from 30 percent to 40 percent.

Carroll Center for the Blind The Carroll Center for the Blind Inc. is a rehabilitation center founded in 1936 by Reverend Thomas J. Carroll.

The center offers a residential rehabilitation program, primarily for newly blinded adults aged 16 and older. The average age of clients in this program is 44. The program specializes in mobility, homemaking, self-care, sensory development, braille, handwriting, record keeping, tape recording, communications, shop, low-vision devices, diabetic care, and individual and group counseling. The program lasts approximately 16 weeks.

The Carroll Center operates computer assessment and training programs for those seeking vocational careers, special educators, high school students, and rehabilitation instructors. Residential options are available for these programs.

The Orientation and Mobility Travel Skills service provides the visually impaired with community instructors who teach clients skills in orientation and mobility and provide low-vision services in their own homes. The Outdoor Enrichment Program allows visually impaired persons to participate in recreational activities year-round. Activities include skiing, ice-skating, hiking, canoeing, sailing, and bicycling. The program matches a sighted guide to each participant.

The center coordinates more than 200 volunteers who serve as drivers, readers, clerical workers, rehabilitation aides, and recreation assistants. It serves as a public information and education source, presents programs on blindness and the curriculum of the center to interested organizations or groups, maintains a 1,000-volume library, and operates an information and referral program.

The Carroll Center publishes a biennial newsletter. It publishes a review of aids for visually impaired consumers and directs a braille menu program to produce copies of menus in braille for restaurants throughout Massachusetts. The center holds a semiannual convention in the spring and fall.

Contact:

Carroll Center for the Blind 770 Centre Street

Newton, MA 02158 617-969-6200 or 1-800-852-3131 617-969-6204 (fax) www.carroll.org

cataract Cataract is a leading cause of blindness in the United States and the world. The National Eye Institute reports that more than half of Americans age 65 or older have a cataract, and, according to Prevent Blindness America, cataracts are responsible for one out of every seven cases of blindness in people 45 years and over.

A cataract is a clouding of the crystalline LENS of the eye, which results in dim or blurred vision. Cataracts may also cause glare or halos in the presence of bright lights or a change in color vision.

One or both eyes may be affected. The individual may have opaque visual areas mixed with clear areas within the same eye. The progressive clouding of the lens is usually slow and may take years to progress to the point where surgery must be performed.

Most cataracts are the natural result of aging. These are termed senile cataracts. Little is known about their cause, although heredity, environment, nutrition and general health may be contributing factors.

Secondary cataracts may be caused by birth defects (congenital cataracts), eye injuries, exposure to ultraviolet or infrared light, medications such as cortisone steroids, or diseases such as DownÕs syndrome, rubella, MARFANÕS SYNDROME, allergic dermatitis, myotonic dystrophy, and diabetes. Diabetics have an increased risk of cataracts and diabetes is present in approximately 10 percentÐ15 percent of cataract patients.

Once a cataract is diagnosed, it is monitored by a physician. Corrective lenses may be prescribed to correct the patientÕs changing vision. Surgery to remove the cataract is performed only when the decreased vision begins to seriously interfere with the patientÕs ability to function.

With over 500,000 operations performed each year, cataract removal is the most common surgery

performed in the United States. There are two main types of cataract surgery: phacoemulsiÞcation and extracapsular. During phacoemulsiÞcation, which is the most common method of cataract removal, a small incision is made on the side of the cornea, and a tiny probe is inserted into the eye. The probe produces ultrasound waves that break up the cloudy center of the lens. The lens can then be removed using suction. In extracapsular surgery, a slightly longer incision is made on the side of the cornea, and the surgeon removes the hard center of the lens. The remainder of the lens is then removed using suction.

Once the cloudy lens has been removed, it is usually replaced with a clear artiÞcial lens called an intraocular lens (IOL). The IOL becomes a permanent part of the eye and does not require any additional care or attention. The person wearing the IOL does not feel or see it. In some cases, patients cannot have an IOL, due to problems that occur during surgery or as the result of another eye problem. In these cases, a soft contact lens or glasses may be used instead.

Prior to surgery, several tests may be performed to determine the power of an intraocular lens implant or the necessity of an implant. The tests may include keratometry, A-scan, B-scan, and an endothelial cell count.

KERATOMETRY is a test to determine the curvature of the CORNEA. A keratometer is used to measure the curvature in order to prescribe the IOL. A nearsighted eye has a more pronounced curve and requires a weaker degree of lens implant than does a farsighted eye. A very nearsighted eye may require such a weak lens as to make an implant unnecessary.

An A-SCAN uses ultrasound to measure the length of the eye. A nearsighted eye is longer than the normal length of approximately one inch. The more long or nearsighted the eye, the weaker the implant lens required. The results of the keratometry and the A-scan are analyzed by a computer to determine the power of the needed implant.

A B-SCAN uses ultrasound to supply a clear picture of a RETINA obscured by a particularly dense cataract. The B-scan can alert the OPHTHALMOLOGIST to a detached retina, which may nullify the effects of successful cataract surgery.

An endothelial cell count is performed to determine the number of healthy endothelial cells remaining in the CORNEA. The endothelial cells line the cornea and protect it from leakage of AQUEOUS FLUID, which could damage vision. The cells are destroyed with aging and as a side effect of surgery. A minimum number of cells, approximately 1,000, is needed to achieve satisfactory results from the surgery. The cells are photographed by an endothelial cell camera, and the resulting photograph is analyzed for cell quantity.

Cataract surgery is performed with either a local or general anesthetic and is usually done on an outpatient basis. The process may take up to an hour with additional time to induce anesthesia. The patient can continue a normal daily routine, with a few exceptions, such as driving.

Postsurgery treatment includes the prescription of glasses for those with the implant and either aphakic spectacles (cataract glasses) or contact lenses plus glasses for those without an intraocular lens implant. It also may include steroid or cortisone eye drops such as Pred-Forte, Inflamase, Ecopred, or Decadron to control inflammation. Antibiotic drops may be prescribed to fight infection, and medication may be used to treat elevated pressure within the eye. Some people experience blurred vision following cataract surgery. This is because the eye from which the cataract has been removed needs time to adjust so that it can focus properly with the other eye. Patients with IOLs may notice changes in colors. Colors may appear to be very bright or have a blue tinge. Exposure to bright sunlight might cause everything to have a reddish tinge for a short period of time. These color sensitivities are not uncommon and should disappear within a few months.

If part of the natural lens remains in the eye, as sometimes occurs, it can become cloudy in time and result in blurred vision. This can occur months or years after the cataract surgery and is called an after-cataract. After-cataracts are usually treated with a YAG laser, which is a type of infrared laser that creates shocks that destroy membranes within the eye. This procedure is called a YAG laser capsulotomy. Normally it is painless and done on an outpatient basis.

Cataracts are one of the leading causes of WORLD BLINDNESS, and are common to all parts of the world. Lack of trained personnel and facilities limits the number of cataract surgeries performed in the third world. World health and governmental agencies operate limited mobile clinics or surgery units to address the needs of those with cataracts in developing countries.

Bath, Patricia E. ÒBlindness Prevention Through Programs of Community Ophthalmology in Developing Countries.Ó In Ophthalmology. Vol. 2. Edited by K. Shimizu and J. Oosterhuis. Amsterdam: Excerpta Medica, 1979.

Freese, Arthur S. Cataracts and Their Treatment, Public Affairs Pamphlet #545. New York: Public Affairs Pamphlets, 1977.

Galloway, N. R. Common Eye Diseases and Their Management. Berlin: Springer-Verlag, 1985.

Helen Keller International. Facts About Helen Keller International. New York: HKI, 1988.

Kelman, Charles D. Cataracts: What You Must Know About Them. New York: Crown Publishing Inc., 1982.

Leßar, Robert B., and Helen Lillie. Cataracts. Washington, D.C.: Public CitizenÕs Health Research Group, 1981.

National Eye Institute. Information for Patients-Cataract. www.neinih.gov, 2000.

Phillips, Calbert I. Basic Clinical Ophthalmology. London: Pitman Publishers Limited, 1984.

Prevent Blindness America, Frequently Asked Questions about Cataracts. www.preventblindness.org, 1998Ð2000.

Reynolds, James D. Cataracts. HealthNet Reference Library. Columbus: CompuServe, 1989.

Shulman, Julius. Cataracts. New York: Simon and Schuster, 1984.

Center for the Partially Sighted (CPS) A comprehensive visual rehabilitation service center founded in 1978 for those with visual impairments but who are not totally blind.

The center offers professional assistance to partially sighted persons in the areas of low-vision examinations, training in the use of loaned and prescribed low-vision aids, professional psychological counseling, support groups, diabetic education groups, transportation services, independent-living skills, orientation and mobility training, and referral to community resources. The center supplies an ongoing follow-up program to assess changing

needs. Patients retain contact with the center through telephone calls or home visits.

CPS maintains an internship program to educate and train interns in the Þeld of low vision and serves as a clearinghouse for information about the partially sighted. It disperses information to the public concerning low vision, low-vision examinations and aids, the location of low-vision services elsewhere in North America, orientation and mobility, and other related topics.

Contact:

Center for the Partially Sighted 12301 Wilshire Boulevard, Suite 600 Los Angeles, CA 90025 310-458-3501 (ph)

310-458-8179 (fax) www.low-vision.org

central vision Central vision is the ÒstraightaheadÓ vision in the visual Þeld. Central vision is controlled by the MACULA, a tiny section of the RETINA. Although the macula occupies only 1 percent of the retina, it is responsible for distinguishing all detail in vision.

The retina is the light-sensitive layer between the choroid and the vitreous gel. It contains RODS AND CONES that receive light information about an object in view. The rods react to faint light, movement, and shape, and are responsible for peripheral or side vision. The cones distinguish color and detail but require high levels of light to function. They are responsible for central vision.

The retina encodes the information from the rods and cones into electrical impulses. The impulses are sent via the OPTIC NERVE to the brain, where they are translated into an image.

The cones of the retina are concentrated into a central section called the macula. Within the macula is an indentation called the FOVEA. The fovea contains the greatest concentration of cones and is the site of sharpest vision. Light is focused by the cornea and the LENS onto the macula, and speciÞcally onto the fovea. When the macula or fovea are damaged, central vision is affected.

MACULAR DISEASE is a common problem affecting central vision. It may be caused by an injury, heredity, other diseases such as arteriosclerosis, or aging.

Age-related maculopathy (ARM) is the most common form of this disease. It is a progressive disease in which the macula deteriorates, and central vision is lost. ARM may in some cases be treated with laser therapy, but there is no cure for the disease. It is seldom responsible for total blindness, since some peripheral vision usually remains intact.

ARTERIOSCLEROSIS, or hardening of the arteries, may cause macular degeneration. In this condition, the arteries become clogged and smaller in diameter. Blood circulation slows, and the bodyÕs organs are denied oxygen. In some cases, the retinal blood vessels become clogged and the macula degenerates.

AMBLYOPIA of disuse, or lazy eye, is a condition that affects central vision. It is a condition of childhood in which one eye is misaligned to the other. The eyes are unable to focus together and double vision occurs. The vision of the misaligned eye is suppressed by the brain, which accepts only information from the aligned eye. In effect, the unused eye ceases to develop and becomes ÒblindÓ or amblyopic. In the treatment of amblyopia, the aligned eye is usually patched to encourage the amblyopic eye to function. The central vision of the amblyopic eye is affected, but it usually retains some peripheral vision.

TOBACCO AMBLYOPIA is a condition in which the excessive use of tobacco impairs central vision. The condition usually rights itself when tobacco use is discontinued or drastically reduced.

The cones responsible for central vision need light to function and to survive. Eyes denied light for long periods may lose central vision. A complete lack of vitamin A in the diet may also result in cone or retinal dysfunction and cause blindness.

cerebral palsy (CP) Cerebral palsy (CP) is not a disease, but rather a group of conditions caused by damage to the motor area of the brain before, during or directly following birth. The condition affects about 500,000 persons in the United States and is the most prevalent lifelong disability in the country.

Over one-third of those with CP are teenagers or young adults. Each year, approximately 5,000

babies are born with CP and an additional 1,500 acquire CP before the age of Þve.

The condition usually involves nerve and muscle dysfunction and may exhibit such characteristics as difficulty in walking; loss of muscle coordination or manual dexterity; spasms; seizures; tremors; hearing, speech, or vision impairments; learning disabilities; mental retardation; and psychological or behavioral problems.

There are Þve types of cerebral palsy: spastic, athetoid, rigid, ataxia, and tremor. Spastic CP, the most common type, involves the trait of tense, contracted muscles. Athetoid CP entails uncontrollable, constant movement of the head, limbs, and body. Rigid CP is characterized by contracted muscles that resist movement.

Ataxia encompasses coordination and balance problems. Tremor CP is the most rare and is similar to the athetoid type since it involves uncontrollable tremors or trembling of the limbs that hinders balance and coordination. Most individuals with CP are affected by more than one type of CP, a condition termed Òmixed type.Ó

Brain damage that results in CP can be caused by acute or chronic anoxia or oxygen deprivation, a result of premature separation of the placenta from the uterine wall, improper birth position, prolonged or abrupt labor, complications during labor, or obstruction by the umbilical cord.

Other congenital causes may include maternal viral infections such as rubella (German measles), Rh and A-B-O blood-type incompatibilities, poor health, excessive smoking or alcohol consumption by the mother, premature birth and untreated jaundice of the newborn causing kernicterus, a disease that involves damage to the nervous system and is also caused by Rh-factor incompatibility.

Acquired CP is a more rare occurrence and results from an injury to the head due to trauma or infection. Cerebral palsy is not hereditary. It is not a progressive condition and is not communicable. Each case of CP is unique. The amount of damage to the brain, the site of damage and the degree to which the nervous system is involved produce varying symptoms.

Vision may be affected if the damage affects the portion of the brain that controls the eyes or the

parts of the eyes that process or transmit information such as the retina or optic nerve. Corrective lenses or surgery may be necessary to improve or correct vision.

Early detection and treatment of CP are essential in achieving the best possible management of the condition. Symptoms of CP in infants may include irritability, difÞculties in feeding or sucking, and abnormally delayed development of muscle control or coordination. Less noticeable symptoms may be detectable by a pediatrician during a medical examination.

Cerebral palsy currently cannot be cured, but management or treatment may reduce the limitations it imposes. Treatment may include physical, occupational, speech, language, hearing, or behavioral therapy. Neurological or orthopedic surgery may increase control over muscles. Braces may strengthen and support the body and correct deformities. Medications may reduce rigidity and ease nerve-damage problems.

Congenital cerebral palsy can often be prevented. Pregnant women can maintain good nutrition, avoid alcohol, smoking, and unnecessary X rays or medications, and control diabetes and anemia. Routine tests for Rh incompatibility in the mother and immunization with Rhogam within 72 hours after delivery can eliminate problems in future pregnancies.

Infants with blood incompatibility may receive a blood transfusion. Premature infants and those at high risk can be monitored closely in neonatal intensive care units. Infants and young children can of course be protected from trauma.

There is much help available for those suffering from cerebral palsy and for their families. The United Cerebral Palsy Association, founded in 1949 as a voluntary organization, has more than 150 state and regional afÞliates. The agency, through its afÞliates, serves more than 30,000 children and adults with cerebral palsy and other disabilities every day. It offers assistive technology training, community living, referrals, employment assistance, advocacy, early intervention programs, therapy, and so forth.

To Þnd out more about the organization that serves your area.

Contact:

United Cerebral Palsy Association 1660 L Street, NW, Suite 700 Washington, DC 20036-5602 800-872-5827 (ph) 202-973-7197 (TTY) 202-776-0414 (fax) www.ucpa.org

Listings of local afÞliates are available from the website.

Mann, Richard C. Diagnosis: Cerebral Palsy. Oklahoma City: United Cerebral Palsy of Oklahoma, 1986.

United Cerebral Palsy Association. What Is Cerebral Palsy? New York: UCPA, 1978.

UCP Net. Cerebral Palsy-Facts and Figures, www.ucp.org, 2001.

chalazion An inßammation of the eyelid gland. It is caused by a blockage of the meibomian gland duct.

A chalazion appears as a bump or swelling on either the top or bottom eyelid. It is painless and may develop slowly over many weeks. Treatment of chalazion may include warm compresses and sulfonamide eye drops.

Once the chalazion has grown large enough to press on the eyeball, it may cause damage to vision by producing an astigmatism. In such cases, surgery to remove the chalazion may be required. The eye is patched after surgery, and antibiotic eye drops are often prescribed.

Chalazions may become chronic. Prevention may be achieved through strict hygiene and the application of warm compresses at the Þrst sign of inßammation. If they do reoccur, it could be an indication of a more serious condition and should be checked.

Child Abuse Prevention and Treatment Act The Child Abuse Prevention and Treatment Act, Þrst enacted in 1974, was amended in 1984 to mandate proper medical treatment of infants born with physical or mental disabilities. The amendments were in response to reports to Congress that appropriate medical treatment was withheld from disabled infants.

The law orders the administration of medical treatment to disabled infants except in the cases of irreversible and chronic coma or if the treatment would only extend the dying process. The law directs state child protection agencies to respond to reports of treatment denial. The act was amended again in 1996 to provide for a community-based family-resource and support-grants program. The program includes temporary childcare for children with disabilities and a crisis nursery program for children who are thought to be at risk.

U.S. Department of Education. Summary of Existing Legislation Affecting Persons with Disabilities. Washington, D.C.: USDE, 1988.

Child Nutrition Act As amended, the Child Nutrition Act of 1966 establishes federal-assistance funds to initiate and manage school-meal programs. The Act outlines programs that supplement and expand those described in the National School Lunch Act. Daytime and residential schools and child-care programs that serve disabled children are eligible to participate in the School Milk, School Breakfast, and Nutrition Education and Training Programs.

The School Milk Program was designed to encourage school children to consume milk. The program funds grants to states to provide free milk to eligible children. Eligible nonprofit schools, child-care centers, and camps are reimbursed for the milk served. Schools and centers are eligible, provided they are not recipients of National School Lunch Act or Child Nutrition Act program funds.

The School Breakfast Program provides breakfasts served at school to eligible children. Eligible nonproÞt public or private schools, including those for disabled children, are reimbursed for the breakfasts.

The Nutrition Education and Training Program provides grants to states for training on nutrition and management to instructors and food-service personnel and instructional nutrition programs in school classrooms. (See NATIONAL SCHOOL LUNCH ACT.)

U.S. Department of Education. Summary of Existing Legislation Affecting Persons with Disabilities. Washington, D.C.: USDE, 1988.

children See DEVELOPMENT OF BLIND CHILDREN.

chlamydia A type of sexually transmitted disease that can cause conjunctivitis, both in adults and babies, who are affected at birth. Caused by a bacterium, chlamydia is the leading sexually transmitted disease in the United States. About 4 million new cases occur each year.

Early symptoms include abnormal genital discharge or pain when urinating, but symptoms can be very mild and may not even be noticed. As the disease progresses, it can cause eye infection and proctitis and urethral infection in men.

Newborns affected while in the birth canal may develop conjunctivitis or pneumonia. Typically, symptoms of eye problems will occur within the Þrst 10 days of life. The eye infection can be treated with antibiotics in both newborns and adults. Many doctors advise that all pregnant women be tested for chlamydial infection because of the risk it presents to newborns.

chorioretinitis A secondary condition caused by CHOROIDITIS, a swelling of the CHOROID (also called posterior UVEITIS). Chorioretinitis occurs when the inßammation of the choroid spreads to the underlying RETINA.

The choroid is the pigmented tissue layer between the retina and the SCLERA (white part of the eye). It is the posterior section of the uveal tract, a vascularized tissue layer that supplies blood to the eye and that includes the IRIS and CILIARY BODY in the anterior section.

The retina is the light sensitive layer at the back of the eye. The retina receives light information from the RODS AND CONES located there. It converts the information into electrical impulses that it sends to the brain. The brain transforms the impulses into an image.

Symptoms of choroiditis include redness of the eye, light sensitivity, and lost or blurred vision. The symptoms of choroiditis may not be noticeable to the patient if they are located in the areas of peripheral vision.

Choroiditis may occur spontaneously. It may also be linked to viruses, injuries, TOXOPLASMOSIS, arthritis, tuberculosis, VENEREAL DISEASE, parasites, and SARCOIDOSIS.

Because of the close proximity of the choroid and the retina, the inßammation of choroiditis

often spreads to the overlying retina, resulting in chorioretinitis. When this occurs the vision becomes acutely blurred. If the inßammation involves the macular region of the retina, permanent central-vision loss could occur.

Chorioretinitis may be treated with systemic (given orally) or local corticosteroids.

choroid The choroid is the dark, middle tissue layer between the RETINA and the SCLERA, or white part of the eye. It is the back portion of the uveal tract, a vascularized tissue layer that supplies blood to the eye. Blood circulates through the choroid layer to nourish and support the eye.

The UVEA or uveal tract contains the pigmented portions of the eye. These consist of the IRIS, the CILIARY BODY, and the choroid. When uveitis, or inßammation of the uvea occurs, the choroid may be involved.

Inßammation of the choroid is called CHOROIDI- TIS or posterior UVEITIS. Symptoms of choroiditis may include pain, redness of the eye, and light sensitivity. However, choroiditis is often present without symptoms, and since it may be present only in the peripheral Þeld, it may persist unnoticed. The inßammation may spread to the retina and the VIT- REOUS, in which case, the vision becomes blurred.

Choroiditis may be caused by parasites (as it is in TOXOPLASMOSIS), viruses, or other diseases such as tuberculosis or syphilis. Choroiditis and posterior uveitis are usually treated with steroid pills, drops, or ointments.

choroiditis Choroiditis is an inßammation of the CHOROID, the vascular layer between the RETINA and the SCLERA. It is a type of UVEITIS, an inßammation of the uveal tract, and is sometimes referred to as arthritis of the eye.

The uveal tract is composed of the IRIS, the CIL- IARY BODY, and the choroid. The iris is the colored part of the eye that controls the pupil and enables it to open and shut to control the amount of light entering the eye. The ciliary body produces aqueous ßuid and moves the lens to focus properly by changing its shape. The choroid, which supplies blood to the eye, is a vascular layer between the retina and the sclera.

Uveitis is categorized as either anterior or posterior. When the iris and ciliary body are involved, the condition is termed anterior uveitis. When the choroid is involved, it is termed posterior uveitis, or choroiditis.

Choroiditis is usually less painful than anterior uveitis. It may be accompanied by redness of the eye, light sensitivity, and lost or blurred vision. The symptoms of choroiditis that occur in the areas of peripheral vision may not be noticeable to the patient.

Choroiditis may occur spontaneously. It may also be linked to viruses, injuries, TOXOPLASMOSIS, arthritis, tuberculosis, VENEREAL DISEASE, parasites, and SARCOIDOSIS. If choroiditis is not treated, it may spread to the retina, a condition called CHORIORE- TINITIS, and to the VITREOUS. Once in the retina, it may affect the MACULA, and result in a loss of central vision.

Choroiditis is treated with steroid pills or drops. Immunosuppressive medications may be prescribed in severe cases. It tends to reoccur.

ciliary body The ciliary body is the group of ciliary muscles that are attached to the ZONULE, a group of Þbers that hold the LENS in place. The ciliary muscles change the shape of the lens when focusing, and they open and shut the PUPIL.

The ciliary muscles contract to bulge the lens forward and focus on a near object. The muscles expand to ßatten the lens and focus on a distant object.

The ciliary body also produces the aqueous ßuid of the eye. The aqueous ßuid ßows through the anterior chamber of the eye where it nourishes the lens and CORNEA and carries away waste. Changes in the ciliary body may affect the production and ßow of the aqueous ßuid, which can result in an increase in intraocular pressure and glaucoma.

Iritis, an inßammation of the IRIS, can cause inßammation of the ciliary body, known as CYCLI- TIS. This results in pain, redness, light sensitivity, and constricted pupil. Iritis and cyclitis are usually treated with steroid pills, eyedrops, or ointments.

Civil Rights Commission Act The Civil Rights Commission is a council that investigates claims of

discrimination and violations of civil rights. The Commission also conducts fact-Þnding examinations and provides the public with information from its clearinghouse. The Civil Rights Commission inßuences public opinion but has no authority to enforce the law against violators.

The Civil Rights Commission Act was amended in 1978 to include provisions that prohibit discrimination on the basis of disability. This allowed the Commission to investigate violations of disabled personsÕ rights.

U.S. Department of Education. Summary of Existing Legislation Affecting Persons with Disabilities. Washington, D.C.: USDE, 1988.

Civil Service Reform Act The Civil Service Reform Act of 1978 authorized widespread changes in federal employment practices. Among other reforms, the Act allowed agency directors to hire assistants for visually impaired or hearingimpaired employees to enable them to do their jobs effectively. These assistants included reading aides for visually impaired employees and interpreters for hearing-impaired employees.

U.S. Department of Education. Summary of Existing Legislation Affecting Persons with Disabilities. Washington, D.C.: USDE, 1988.

closed-circuit television (CCTV) A low-vision aid that electronically magniÞes a distant object or printed material. It is widely used by visually impaired persons in schools, libraries, ofÞces, and homes.

The CCTV consists of a video camera with a zoom lens and a monitor. The camera focuses on print material or distant objects such as a blackboard and electronically transmits the enlarged image to a video monitor. The user employs hand or foot controls to scan the material and focus on a speciÞc sentence, phrase or word. The user may choose to see the print as black letters on a white background or white letters on a black background.

The CCTV can magnify objects or print from 1 to 60 times normal size without distortion. Since it operates on electronic image intensiÞcation rather than optical projection, the image contrast and the