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

macula The macula is the central section of the RETINA responsible for clear central vision. It is located in direct line of sight with the PUPIL.

The retina, which contains the macula, is Þlled with RODS AND CONES. These light-sensitive cells supply information to the eye about the image seen. The rods react to faint light, movement, and shape. The cones distinguish color and detail but require higher light levels to be effective. The macula contains the greatest number of cones.

Within the macula is an indentation called the FOVEA. The fovea contains the greatest concentration of cones and is the site of sharpest vision. Because the cones require light to work, incoming light is focused by the eye onto the macula, centering on the fovea.

The macula is subject to degeneration. Macular disease may be caused by heredity, other diseases such as arteriosclerosis, or aging. ARM, or agerelated maculopathy is the most common type of degeneration. It is a disease in which the macula deteriorates, causing a loss of central vision. The disease may involve hemorrhaging from fragile blood vessels beneath the retina. ARM is a progressive disease that may worsen over time. It may effect one or both eyes. The disease is seldom responsible for total blindness since the patient usually retains some peripheral vision.

macular disease Macular disease is the leading cause of new cases of blindness. The Macular Degeneration Foundation, an educational and research organization founded in 1989, estimates that more than 1.2 million American are affected by this disease and that a new case of adult macular disease is diagnosed every three minutes in the United States.

M

Macular diseases of the eye that cause deterioration to the macula, or central part of the RETINA. This results in a loss of vision in the central Þeld. The macula is centered in the retina, a light-sensi- tive layer in the back of the eye. Light reßected off an object is focused onto an indentation of the macula, called the FOVEA. The fovea is the point of clearest sight.

Cones in the fovea interpret the light into information about the object. This information is encoded into electrical impulses by the retina and sent to the brain via the OPTIC NERVE. The brain translates the impulses into an image.

There are two major types of macular disease. The Þrst, inherited macular dystrophies, usually occur before the age of 20. These inherited diseases are rare and usually incurable.

The more common form of macular disorder is called age-related maculopathy, or ARM. It is most common in people who are over 60, but can appear as early as age 40.

It is thought that the disorder is caused by a breakdown in the blood supply to the retina. It may also develop due to an infection, ocular trauma or injury, drugs, other diseases such as diabetes, or heredity.

ARM may fall into one of two categories: wet type or maculopathy. The wet type occurs when new delicate blood vessels form in the CHOROID, a vascular layer of tissue beneath the retina. When these abnormal vessels break or leak into the macula, healthy cells are destroyed and vision loss occurs in that central area. Maculopathy does not involve ßuid leakage.

ARM is a progressive disease that may worsen rapidly or slowly over time. The onset usually takes place in one eye Þrst, to be followed by an occurrence in the other eye, two or three years later. The

condition may Þrst present itself as a blurring of vision. Printed type may look blurred, vertical lines may look wavy, and central vision may appear blocked or distorted.

Age-related maculopathy can be detected during the normal ophthalmological examination. Those over 50 years of age are routinely screened for the disease. During the exam, the ophthalmologist looks for changes within the retina and choroid. The presence of new blood vessels beneath the retina may be signs of possible degeneration development. The presence of drusen, small whitish spots of waste material scattered on the posterior pole may indicate a propensity for development of the disease.

The patient may also be tested for age-related maculopathy with the Amsler grid. This is a grid with a dot in the middle of two intersecting lines. With one eye covered, the patient looks at the dot. If the patient is unable to see some of the lines or if some lines appear wavy or kinked, ARM may have occurred.

Fluorescein angiography may be performed to view the retinal blood vessels. This is a test in which a ßuorescent vegetable dye is injected into a vein in the arm. As the dye travels throughout the body and into the retina, a series of photographs are taken. The photographs point out any irregularities within the retinal vascular system.

Doctors and scientists have been working hard to learn more about ARM. A new drug, Visudyne, was recently approved for treatment of the wet form of ARM. Physicians are hopeful that this drug will begin a series of advancements in the treatment of this disease. But since the peripheral Þeld of vision remains unaffected, it is possible to learn to use the remaining vision to the best advantage. Special viewing techniques and optical aids such as telescopic lenses may be prescribed.

In approximately 10 percent of cases, laser photocoagulation treatments can improve the condition. These treatments use LASERS to cauterize and seal the abnormal leaky vessels of wet type ARM. It is usually a painless procedure, performed on an out-patient basis.

Early diagnosis is critical to the treatment of macular degeneration. If the disorder is caused by drugs or infection, the drugs can be discontinued or

the infection treated before further damage can occur. Photocoagulation is most successful in the early stages, since it becomes impossible once the vessels develop near the center of the macula or once the infusion of blood conceals the vessels.

macular edema A condition of the macula stemming from retinal edema. The macula is an indentation of the retina that contains an abundance of cones, light-sensitive cells that are responsible for discerning color and detail. Light is focused directly on the macula by the eye, making it the center of sharpest sight.

Retinal edema occurs when the capillaries of the retina bleed, Þlling the spaces between retinal cells with ßuid. Retinal edema may be present throughout the retina and involve the macula, or it may contained in a general area that spares the macula. If the macula is spared, vision may be relatively unaffected at Þrst. However, the macula tends to accumulate the ßuid. In this case, macular edema occurs. The condition is characterized by inßammation of the macula and blurred or impaired vision. If untreated, macular ßuid collects in small pockets of space and forms cysts, a condition called cystic macular edema. The condition leads to degeneration of the macula in which central vision may be permanently lost.

Macular edema is caused by diabetic retinopathy, hypertension, retinal vein obstruction, traction of the vitreous, inßammations such as UVEITIS and RETINITIS, and CATARACT surgery. It is diagnosed with fluorescein angiography, a procedure in which ßuorescein dye is injected into a vein in the arm and monitored as it passes through the veins of the retina. Macular edema may right itself spontaneously or persist. Treatment of the condition varies according to the cause. Cases due to inßammation are treated with corticosteroids.

Those conditions of edema caused by vascular problems and diabetes may be treated with photocoagulation, a treatment that uses a laser to seal leaking blood vessels. There is no treatment for edema due to traction or cataract surgery.

magnifiers MagniÞers and other optical aids are used to increase the size of an image. MagniÞers

improve close vision for reading and writing tasks. These LOW-VISION AIDS range from the inexpensive dime-store magnifying glass to sophisticated, expensive video equipment.

Placement-type, hand-held, and stand magniÞers are available in a wide range of sizes and strengths and come with or without built-in illumination. Bar magniÞers are plastic bars that are placed on one line of print to double the original size. Page magniÞers are sheets of plastic placed over a page to magnify the print. Both are available without prescription.

Hand-held magniÞers range from 3X to 10X magniÞcation. Some are modeled after a ßashlight and include illumination. These are used for nearvision tasks such as short-term reading. Hand-held magniÞers are not suitable for long periods of reading and writing due to unsteadiness of the hand.

Stand magniÞers are available in 3X to 10X magniÞcation and are mounted on a stand that is placed over the document to be read. The stand places the magniÞer the proper distance from the material and frees the hands. Stand magniÞers are generally used with reading glasses.

A loupe, or spectacle magniÞer, is a convex lens that clips onto an eyeglass frame. The lens is attached to the frame by a thin, metal arm and swings down into position just in front of the eyeglass lens. Two or more loupes can be simultaneously mounted on the frame to accommodate work or reading done at different distances.

Electronic magnifying systems are more complex and expensive. Video magniÞers, such as closed-circuit television or CCTV, enlarge an original print image up to 60 times. The image is displayed on a large viewing screen. These devices can change the dark letters on a white Þeld of the original to white letters on a dark Þeld to increase contrast and visibility. Many users can use the CCTV to write, type and operate a computer.

High-powered, portable magnifying devices are rapidly becoming available. Small and lightweight, these aids are powered by rechargeable battery packs. They scan print information with a camera mounted on rollers and magnify the image four to 64 times the original size. The image is projected onto a display monitor in either orange print on a black background or the reverse.

Telescopes are commonly used optical aids. They may be hand held, fused into spectacle frames, incorporated into prescription lenses, or worn on a headband. Binocular hand-held telescopes are used for distance magniÞcation and are available in various magnifications. Hand-held binocular telescopes are adjustable and may be used with one or both eyes. They are used with both eyes for viewing sports events, television, and street signs. When used with one eye, binoculars produce a smaller Þeld of view and are used for near and intermediate distance viewing in tasks such as reading or writing.

Binocular telescopes may be fused into spectacle frames for convenience of use. These are used for distance viewing of sports events, television, stage productions, etc. They produce a small Þeld of view and are available in 3X magniÞcation. Binocular spectacles are available without a prescription but cannot be used if a prescriptive correction is necessary.

Hand-held monocular telescopes are available for use with one eye in magniÞcations up to 10X. They are used for distance of viewing sports or television or in school but are not recommended for walking. Variations of the hand-held monocular telescope may be attached or fused onto prescriptive lenses. Attached versions are available in magniÞcations up to 3X, and fused versions up to 4X magniÞcation.

Bioptics are optical aids that consist of small telescopes fused onto the upper portion of spectacles, on one or both lenses. The bottom portion of the spectacles contains the individualÕs corrective prescription. The bioptics involving both eyes enables the user to view distances when walking or driving or to view closer objects or material if magniÞcation is needed. The bioptics that involve one eye only are used for near and intermediate distance viewing for reading material. Bioptics are prescribed by an ophthalmologist or low-vision expert and must be properly centered to the eyes of the wearer. MagniÞcation may extend to six times normal size when used for distance viewing. Wideangle and zoom lenses may be incorporated into the device.

Near telescopes are fused onto the lower portion of the spectacle frames, with the prescriptive lenses

in the upper portion of the frame. They are available up to 8X magniÞcation and are effective for Þve to 40 inches. The telescopes are angled to be used by both eyes and are used for intermediate distance tasks such as reading or typing.

Headband telescopes are attached to a headband and free the hands for work. They can be worn over prescriptive lenses and are used for near viewing up to one foot or less. They afford a wide Þeld of vision and are most effective for those with equal sight in both eyes.

Some new systems combine the camera and display screen in a hand-held housing. A vacuum-ßu- orescent display makes a magniÞed image appear as the camera is moved across the reading material. There also are some new systems that use headmounted displays, providing portability and a new way of viewing. More information and reviews of various CCTV systems are available by contacting the National Technology Program:

212-502-7642 (ph)

212-502-7773 (fax) techctr@afb.net

mailing privileges Materials may be mailed free of postage by legally blind individuals or those unable to read or use conventionally printed materials as a result of a physical disability. The program is entitled ÒFree Matter for the Blind or Handicapped.Ó

In order to become eligible, the individual must present written certification by a competent authority to the post ofÞce where mailings will be sent and received. An authority may include a licensed doctor, ophthalmologist, optometrist, registered nurse, or professional staff member of a hospital or other agency or institution.

Material eligible for mailing includes books, magazines, musical scores, braille material, 14point Sightsaving Type, records, or cassette tapes. Equipment and parts of equipment used for writing or educational purposes, sound play-back equipment for use by the visually impaired, and equipment designed or adapted for use by visually impaired persons, such as braille watches and white canes are also eligible.

The material must be free of advertising and must be speciÞcally designed for and used by visu-

ally or physically disabled individuals. The mail is subject to inspection by the Postal Service.

Noncommercial agencies or organizations, individuals, and libraries serving eligible persons may mail the material to an eligible person or organization free of charge. The eligible person may exchange or return material postage free to other eligible persons or organizations. Commercial producers of this material may mail it free of postage to an eligible individual or organization so long as the fee, charge, or rental does not exceed the cost of the material.

Eligible persons may send letters in braille, large print, or recorded form. Handwritten or typed letters are subject to postage when mailed to or from an eligible person. Letters must remain unsealed to allow inspection by the Postal Service. All mailed material must be stamped, printed, or handwritten with the words. ÒFree Matter for the Blind or HandicappedÓ in the space reserved for postage. Free international delivery of some materials also is included. Special services, however, such as Express Mail or CertiÞed Mail, are not included.

mainstreaming A term used to describe the practice of educating disabled students, including those with visual impairments, in a standard, public classroom for non-disabled children.

Federal law requires that all disabled children be given a free, appropriate public education in the least restrictive environment. This environment has often been equated with mainstreaming.

The mainstreaming movement grew out of a need for the education of a large population of visually impaired children who were blinded by retrolental Þbroplasia during the early 1950s. At that time, the most popular form of education, residential schooling, was unable to immediately provide for the inßux of students.

Parents organized to insist that their children be allowed into public schools and that special education be provided according to their needs. Today, although residential schools still provide vital education and training services, the American Foundation for the Blind estimates that nearly 90 percent of disabled students receive all or part of their education in local public schools.

Students may be mainstreamed into a public school program through several models of delivery, including the itinerant-teacher model, and the teacher-consultant model, and the resource-room model.

The ITINERANT TEACHER is one who travels every two or three days to each public school in the district to provide special education modiÞcations to mainstreamed visually impaired children. The teacher provides special equipment, training, and materials adapted to the studentÕs learning needs and consultation services to the regular classroom teacher.

The TEACHER-CONSULTANT is a special educator who advises regular classroom teachers, teacher aides, administrators, and other school personnel in methods that will meet visually impaired studentsÕ needs. The greatest proportion of the work is consultative, rather than instructive.

The RESOURCE ROOM is a specially equipped room staffed with special education personnel trained to work with disabled students, including those with blindness or visual impairments. The students live at home and attend public school in regular classrooms taught by teachers who provide general curriculum instruction. Students visit the resource room at regularly scheduled intervals or when needed.

Students may be technically mainstreamed into a public school system through a schoolÕs SELF-CON- TAINED CLASSROOM for the disabled. This is a classroom in a public school that is specially equipped and staffed with special education teachers for the disabled. All the students in the class have visual impairments or other disabilities.

Many children, often those with low vision or other disabilities that do not interfere with educational progress, attend their local public schools without special-education support.

Scholl, Geraldine, ed. Foundations of Education for Blind and Visually Handicapped Children and Youth. New York: American Foundation for the Blind Inc., 1986.

Scott, Eileen P. Your Visually Impaired Student. Baltimore: University Park Press, 1982.

A tumor of the eye that grows from melanin-laden cells in the CHOROID,

IRIS, or CILIARY BODY. Also called an intraocular melanoma. According to the U.S. Department of Health and Human Services, malignant melanomas account for up to 80 percent of all eye malignancies, making them the most common primary (originating in the eye) inner-eye tumor. The tumor may develop from a mole or spontaneously and is usually slow to grow and spread. It generally affects one eye only (unilateral), may appear at any age and is more common in whites than blacks. Symptoms include redness of the eye, inßammation, vision loss, and the presence or development of GLAUCOMA. Melanomas of the iris may distort the shape of PUPIL.

A melanoma can be detected in the ophthalmologic examination. It may Þrst appear to be a choroidal hemorrhage, but can be identiÞed further by FLUORESCEIN ANGIOGRAPHY or ULTRASONOG-

RAPHY.

Three types of treatment are commonly used for intraocular melanomas. They are: surgery, radiation therapy, and photocoagulation. Surgery is the most common treatment. It can involve removing a portion of the diseased eye, or enucleation, which is the removal of the entire eye. Radiation uses X rays and other high-energy rays to kill cancer cells and shrink tumors. It can be used by itself, or in combination with surgery. Photocoagulation treats the melanoma by destroying blood vessels with a tiny beam of light, usually from a laser. Destroying the blood vessels kills the tumor.

Clinical trials to test other treatment methods are ongoing. More information about the trials can be obtained by calling (toll free) the National Cancer InstituteÕs Cancer Information Service at 800- 422-6237. If the diagnosis is uncertain, a period of observation may be prescribed, possibly including chemotherapy or radiation treatments.

Little is known concerning the cause of malignant melanomas. Unlike skin or conjunctiva melanomas, sunlight exposure is not related to these tumors. Limited data exists concerning metastatic rates (growth or spread of tumor) and spontaneous regression rates

National Cancer Institute. ÒWhat is Intraocular Melanoma?Ó NCI website: www.cancernet.nci.nih.gov, 2000.

Marfan’s syndrome MarfanÕs syndrome (arachnodactyly) is a rare genetic disease. It is characterized by long, thin bones, elongated limbs, especially of the extremities, tall slender Þgure, lack of subcutaneous fat, nonelastic ligaments, congenital heart disorders, high infant-mortality rate, malformations of the spine, joints, and ears, and ocular disorders.

Ocular disorders include dislocation or subluxation of the LENS, serious refractive errors (nearsightedness, far-sightedness, etc.), GLAUCOMA,

CATARACT, and uveal COLOBOMAS. IRIDONESIS, or a trembling of the iris, also associated with MarfanÕs syndrome. The most common symptom, subluxated lens, is a condition in which the lens becomes displaced in an up and out direction.

The subluxated lens may increase myopia and cause ASTIGMATISM or cataracts. Often, the displaced lens blocks or narrows the angle of the ANTERIOR CHAMBER and causes secondary glaucoma. If glaucoma cannot be treated successfully with medications or surgical procedures, the lens may be removed. In some cases, aphakic (without lens) patients may experience corrected vision with aphakic spectacles or contact lenses.

For more information contact:

The National Marfan Foundation 382 Main Street

Port Washington, NY 11050 800-8-MARFAN (ph) 516-883-8040 (fax) www.marfan.org

Maternal and Child Health Services Program

The Maternal and Child Health block-grant program evolved from the original Sheppard-Tower Act of 1921. Also known as the Maternity and Infant Act, it was the Þrst national health services grant program. In 1935, the act was amended and revised by Title V of the Social Security Act to include services for disabled children.

Amendments to Title V in 1963 authorized a grant program to improve health and prenatal care for low-income women. The effort was designed to reduce preventable mental retardation and birth defects. The legislation provided funding for research studies and additional grant

funds for states under the Maternal and Child Health program and the Crippled ChildrenÕs program.

The Social Security Act Amendments of 1965 extended and improved health-care services for mothers and children. Project grants were established to develop maternal and childrenÕs healthcare programs and comprehensive training services for specialists working with disabled children. Project grants were authorized to support and improve health-care services to low-income school-age and preschool-age children.

In 1967, amendments to the Social Security Act combined the separate Crippled ChildrenÕs Service grants and Maternal and Child Health Services grants into one authorization. One-half of the funding was allotted to formula grants; the other half was divided 40 percent for project grants and 10 percent for training and research. In 1981, this grant authority was consolidated with those for all the programs established in Title V into one state block-grant authority by the Omnibus Budget Reconciliation Act.

The words Òcrippled childrenÓ were removed from the wording of the Act in 1985 and the words, Òchildren with special health-care needsÓ was substituted. In 1986 and 1987, appropriations were raised for the Maternal and Child Health program.

Block grants awarded to the states may be used to provide health-care services, and fund development, administration, training, education and evaluation of the programs. According to the OfÞce of Special Education and Rehabilitative Services, the law authorizes the states to use MCH block-grant funds to:

¥Assure mothers and children access to quality health services

¥Reduce infant mortality, preventable diseases, and disability conditions among children

¥Reduce the need for in-patient and long-term care services

¥Increase appropriate child immunization

¥Increase health assessments and follow-up diagnostic and treatment services for low-income children

¥Provide preventative and primary-care services for children and prenatal, delivery, and postpartum services for low-income mothers

¥Provide rehabilitation services for blind or disabled children under 16 who receive Supplemental Security Income beneÞts

¥Provide information services regarding diagnosis, hospitalization, and after-care for children who have disabilities or conditions that may lead to disabilities

¥Provide for Special Projects of Regional and National SigniÞcance (SPRANS), research and training for genetic disease testing, counseling, and information dissemination

¥Provide grants relating to hemophilia and sudden infant death syndrome

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

Maxi Aids Inc. Maxi Aids is one of the largest suppliers of adaptive living aids in the United States. Formerly known as Seeing Technologies Inc., the company has an extensive on-line catalog and also offers traditional catalogs of its products.

It offers products including alarm vibrators, adaptive calculators, canes, CCTVs, computer products, games, personal need devices, glasses, kitchen and cooking adaptive devices, mobility devices, magniÞers, radios and recorders, paging devices, sensory products, talking products, and telephones.

Contact:

Maxi Aids

42 Executive Blvd. Farmingdale, NY 11735

631-752-0521 or 1-800-522-6294 (to place an order)

631-752-0738 (TTY)

631-752-0689 (fax) www.maxiaids.com

Medicaid legislation In 1965, amendments to the Social Security Act added Title XIX, a grants program that allowed states to establish medicalassistance systems. Title XIX extended the Kerr-

Mills medical-aid program for low-income blind and disabled individuals and dependent children.

The new program became known as Medicaid. Unlike Medicare, it allowed states to offer coverage not only to those who receive public assistance, but also to eligible needy people who did not qualify for welfare or Medicare. The program varies from state to state.

Although the original legislation of 1965 made no specific reference to disabilities, Medicaid has become the main source of medical services funding to severely disabled individuals. In 1992, U.S. federal and state budgets included $118 billion in Medicaid benefits. This may be because later amendments added specific benefits for mentally ill and mentally retarded institutionalized individuals, and because the funding targets lowincome groups where the incidence of disability is greater.

Medicaid eligibility is determined by Þnancial need. Recipients generally fall into one or more of the three qualifying categories: categorically needy, medically needy, or qualiÞed severely impaired.

The categorically needy receive AID TO FAMILIES WITH DEPENDENT CHILDREN (AFDC) beneÞts or SUP- PLEMENTAL SECURITY INCOME (SSI) beneÞts or qualify under speciÞc regulations for their state.

Medically needy persons may have incomes too high to qualify for AFDC or SSI beneÞts yet cannot afford to pay for necessary medical treatment. States determine a different qualifying income level for those who are medically needy.

Qualified severely impaired individuals are those under 65 who receive federal SSI beneÞts because of blindness or disability and are able to be employed but do not have incomes that allow them to pay for health-care coverage.

Medicaid provides hospital services, both inpatient and outpatient, as well as laboratory tests or X-ray services. Special nursing facility services and, for those over 21 years old, home health services are also provided.

The beneÞts cover the recipientÕs doctor services and diagnostic tests such as those classiÞed as EPSDT, or early periodic screening, diagnosis and treatment services, for those under 21. Additionally, some rural health-clinic care and family-plan- ning services are also provided under the plan.

States must arrange to transport recipients to and from medical services if needed; they must allow the recipient to choose the medical caregivers and must provide health-care services statewide. If adequate medical care is provided, states may limit the quantity, extent, and range of these services.

If listed in the state plan, the state may provide any optional services that are allowed under state law and permitted by the Secretary of Health and Human Services. Since each state designs a program to meet the speciÞc needs of its citizens, coverage differs greatly from state to state.

The optional services may include private nursing, health-clinic, and dental services. Physical and occupational therapy and rehabilitation services may be covered, as well as hearing, speech, and language therapy or treatment.

The plan may include prescriptions such as drugs, eyeglasses, dentures, prosthetics, and prosthetic aids. Other services may include those not covered speciÞcally under federal law in such areas as diagnostic screening, inpatient hospital procedures, nursing or intermediate-care facility services, in-patient psychiatric treatment for those under 21 or over 65, and case-management services for speciÞc categories of eligible people.

U.S. Department of Education. Summary of Existing Legislation Affecting Persons with Disabilities. Washington,

¥People with childhood disabilities who qualify for Social Security beneÞts

¥Disabled widowed persons, 50 years of age or older

¥Diagnosed as having an end-stage renal condition

In 2001, nearly 40 million people in America were eligible for some Medicare health coverage. Medicare has two parts: Part A is hospital insurance and Part B is medical insurance. Part A helps pay for necessary in-patient and limited home services including hospital or emergency-room care, nursing facilities, hospice services, and some homehealth care.

Part B of the insurance plan helps pay for doctors, services, outpatient hospital care, and other medical treatment not covered by Part A. Services covered by the plan are paid according to reasonable costs and fee schedules. Any eligible individual may register for Part B beneÞts. Although the individual is required to pay a monthly premium, some states or other agencies may pay the premium for a disabled person.

At the end of March 2001, a bill was pending in Congress that would make orientation and mobility specialists, rehabilitation teachers, and lowvision therapists eligible providers under Medicare.

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

Health Care Financing Administration. ÒMedicare Basics.Ó www.medicare.gov, 2001.

migraine A migraine is a type of recurrent headache. It differs from the normal tension headache in that it usually affects one side of the head only and is often accompanied by visual disturbances, nausea, and vomiting.

Migraines are thought to be caused by a sudden dilation of the arteries in the brain and scalp following a period of spasm or narrowing. The sudden expansion of the arteries causes the blood to surge against the artery walls and surrounding tissues. The dilation and constriction may occur when the body over-produces serotonin and norepinephrine, amines or biological substances that

dilate and constrict blood vessels of the body and brain.

Migraine attacks tend to run in families and may be triggered by a variety of causes. It is estimated that between 11 and 18 million Americans suffer from migraines, most of them women. In addition, it is estimated that up to 38 million Americans have the genetic propensity for migraines. The following have been linked to migraine attacks: intense direct, reßected, or ßickering lights; rapidly changing images, sudden or persistent noises; reaction to stress; strong odors; allergies; hypertension; hormonal changes; nitroglycerin; anesthetic; drugs; alcohol; cheese; chocolate; cured foods; MSG; poor ventilation; change in barometric pressure; exercise; tight clothing; steam; motion; dental problems; a shock or blow to the head; and too little or too much sleep.

The two major categories of migraine headaches are common and classic. Each is preceded by a preheadache state, called the prodrome stage, which may last from Þve minutes to an hour. During this stage, symptoms of the oncoming migraine may be noted. They include nausea, vomiting, weakness or tingling on one side or section of the body, mental confusion, fatigue, irritability, dizziness, pallor, euphoria, water retention, and lack of coordination.

Common migraines are associated with light, noise or odor sensitivity, and vomiting or nausea. Classic migraines may include these symptoms but are further characterized by visual disturbances. Patients may experience blurred vision, TUNNEL VISION, double vision, SCOTOMAS, scintillating scotomas, fortiÞcation spectra (angled, shimmering lines), HEMIANOPSIA, or distorted vision.

Blurred vision is common to migraine attacks and may be accompanied by tunnel vision, the loss of peripheral or side vision. Tunnel vision has been described as vision seen when looking through a straw. Double vision, or DIPLOPIA, may result during a migraine if ophthalmoplegia, paralysis of the eye muscles, occurs. When a muscle is paralyzed, one eye moves out of alignment and the brain receives two images instead of one, or double vision.

Scotomas are blind spots in the Þeld of vision of one or both eyes. The vision in the scotoma may be blurred or completely obliterated. Scintillating scotomas are blind spots that shimmer with bright

light to block out vision. Scotomas may appear anywhere in the Þeld of vision and may move during the course of the prodrome stage or during the headache stage.

FortiÞcation spectra is a shimmering, glittering pattern of bright or colored lights in the Þeld of vision. The lights form shapes such as auras or semicircles and appear in zigzag formations much like a prism. They may block vision or lie atop it.

Hemianopsia is a decrease or loss of vision in one half of each eye. The entire right or left half of the Þeld of vision may be obliterated or may be blocked by fortiÞcation spectra.

Distorted vision may result from migraine. Objects or people may appear elongated or stretched out of shape as by a funhouse mirror. This phenomenon is sometimes called the Alice in Wonderland syndrome in reference to the distorted Þgures pictured in Alice’s Adventures in Wonderland.

The author, Lewis Carroll, was said to have suffered migraines and collaborated closely with the illustrator to produce illustrations that captured the visual effects he experienced.

The visual effects of the prodrome stage may disappear with the onset of the headache or my overlap. When the visual symptoms occur, but a headache does not follow, the condition is known as a migraine equivalent.

The migraine headache itself is often severe. It usually affects only one side of the head and may include the face, extending as far as the jaw. Patients may experience light sensitivity, head, neck, and scalp sensitivity or tenderness, nausea and vomiting. The headache may last from one to 24 hours. In rare cases, the headache may last for days.

Migraines can occur at any time of life. They may appear in children as recurring attacks of headache and vomiting or as migraine equivalents. The attacks may disappear or return later in middle life. Migraines can occur for the Þrst time in middle age and may decrease in regularity as time goes on. Women are more likely to suffer from migraines, but the problem tends to improve with menopause.

At present, there is no cure for migraines. Analgesics such as aspirin and acetaminophen or either compound with codeine may be taken to ease pain at the Þrst sign of the headache. Severe pain is