4 questions | Applied Sciences homework help

1. Erectile dysfunction: Penile prosthesis. WebMD Web site, Feb 23, 2011.

HealtH Devices question: What [device] can reduce bothersome background noise, magnify nearby conversation, allow you to focus on sounds you want to hear, overcome nerve deafness, and improve speech clar- ity? answer: Nothing. aarP senior Consumer alert1 © don de lorimier “It’s not like the old days.” Chapter Twenty Part Five Other Products and Services420

• Medical device regulation needs considerable reform.
• The most important step toward purchasing eyeglasses or contact lenses is a thorough professional examination.
• Although hearing aids can make sounds louder, they may not improve intelligibility in noisy areas because background noise can be amplified along with speech sounds. Before buying a hearing aid, medical evaluation is advisable.
• Quack devices are a significant problem.

Keep tHese points in MinD as You stuDY tHis cHapter Key Concepts Medical devices include several thousand types of health products, from simple articles such as thermometers, heating pads, contact lenses, and hearing aids to complex medical equipment such as heart pacemakers, kidney dialysis machines, and lasers used for surgery. Federal laws define “medical device” as any health-care product that does not achieve any of its principal intended purposes by chemical action in or on the body or by being metabolized.2 (Products that work by chemical or metabolic action are defined and regulated as drugs.) The term “devices” also includes laboratory equipment; diagnostic test kits; and compo- nents, parts, and accessories of medical devices. Total sales of medical devices and diagnostic products by publicly traded corporations in the United States exceed $200 billion a year.3 In most cases where consumers encounter a device used by or prescribed by a physician, they have little need or opportunity to make a choice. It would be pointless, for example, for a patient whose blood pressure is being checked to attempt to determine whether the instrument is designed well and calibrated properly. Nor would it be appropriate or even possible for someone undergoing general anesthesia to evaluate the quality or reliability of the equipment that is used. The only practical way for consumers to protect themselves is to choose competent practitioners who presumably select and maintain their equipment properly. This chapter emphasizes devices (and related servic- es) about which consumers frequently make decisions: eyeglasses; contact lenses; sunglasses; hearing aids; water purifiers; humidifiers and vaporizers; and personal emergency response systems. It also calls attention to the little-publicized problems of spinal decompression machines, latex allergy, and quack devices. MeDical-Device regulation The Food and Drug Administration (FDA) is responsible for device regulation. It has the extremely difficult task of trying to keep unsafe or ineffective products off the market while ensuring timely access to new ones. The current classification system has three classes based on (a) the extent to which use of the device involves mat- ters of life or death or serious injury and (b) whether the device is entirely new or is similar to a previously approved device. The Historical Perspectives box traces the history of device regulation. Most Class I products are subject only to the general controls that apply to all devices. These include regis- tration of manufacturers, recordkeeping requirements, labeling requirements, and good manufacturing practice regulations. Most of the devices in this category are simple products such as bandages, tongue depressors, bedpans, dentures, orthopedic shoes, and other items in which failure is unlikely to cause serious harm. Most Class I products do not require permission from the FDA before they can be legally marketed. Class II products must meet performance standards established by the FDA. However, only a few such stan- dards have been written. To market a new Class II device, the manufacturer usually must get permission through a process called “premarket notification,” commonly referred to as a “510(k),” which is the section number of the relevant regulation. This regulatory pathway can be used for devices “substantially equivalent” to others already approved. The amount of substantiation is much less than would be required for a device that is entirely new. More than 98% of the devices marketed today have gone this route. The permission granted under 510(k) is properly described as “clearance.” It is illegal to represent 510(k) clearance as “FDA approval” or to market devices for uses that have not been cleared, but manufacturers sometimes do so. Class III products are usually devices that are en- tirely new and involve life support and other critical functions. Cardiac pacemakers and heart valves are examples. Most Class III products require premarket approval (PMA) based on substantial evidence that they are safe and effective for their intended uses. The Chapter Twenty Health Devices 421 Historical Perspective FDA jurisdiction over devices began with passage in 1938 of the Food, Drug, and Cosmetic Act (FD&C Act), which required that devices be safe and labeled with adequate directions for use. Premarket approval from the FDA was not required. The burden of proving that a device was dangerous or ineffective fell upon the FDA. To stop the marketing of a dubious device, the agency often had to expend much time, effort, and expense for research and court procedures. As legitimate devices became more sophisticated and more numerous, it became clear that the 1938 law did not adequately protect the public. The 1976 Congress amended the law to require that all devices be safe and effective, that new devices have premarket clearance, and that manufacturers bear the burden of proof. The Medical Device Amendments divided medical devices into three classes (I, II, and III) based on the principle that the greater the potential hazard, the more rigorous the regulatory requirements and the higher the class.4 The Medical Device Reporting Act (1984) required for the first time that adverse reactions and significant malfunctions be reported to the FDA. Within the first 3 years after it took effect, 1554 device-related deaths and 21,176 nonfatal injuries were reported.5 In 1989 the General Accounting Office reported that only about 25% of the expected number of device manufacturers had filed problem reports. FDA inspectors found that many firms were unaware of the reporting requirement, and some had records of deaths and serious injuries that had not been reported to the FDA. After it became apparent that the 1976 law needed further reform, Congress passed the Safe Medical De- vices Act of 1990. This extended the reporting require- ment to hospitals, nursing homes, and outpatient facilities (except physicians’ offices), and also requires notification by manufacturers. The 1990 law also enables the FDA to order an immediate recall of any device it deems unsafe and to initiate large civil penalties for violations of the act (see Chapter 25). While underreporting of device- associated problems has decreased, the result is not en- tirely positive. As of April 2011, the FDA’s Manufacturer and User Facility Device Experience (MAUDE) database of adverse events had accumulated more than 9.6 million entries, far more than the agency can usefully manage. Knowledgeable observers believe that reporting should be limited to problems that may contribute to serious injuries and deaths.6 Criticism by Congress and others of the FDA’s medical-device regulation has suggested that the public is not adequately protected. The Government Accountability Office (GAO)7 reported that in fiscal years 2003 through 2007, more high-risk devices entered the marketplace through 510(k) clearance than through PMA. Zuckerman and others8 found that from 2005 through 2009, only 21 of 113 (19%) devices that had been recalled for serious potential health problems or death had been approved by the stringent PMA process. In response, the FDA is considering tighter 510(k) regulation. The FDA also requires manufacturers of new devices to document that they have tried to design their devices so that user errors are minimized. Robert Mosenkis,9 who for many years served as editor of Health Devices (a magazine similar to Con- sumer Reports but written for large purchasers of medi- cal devices), believes that the quality of medical devices generally is high and that “the device industry is . . . very effective at policing itself, if only because of the large awards being made in liability suits.” Device Regulation evidence must include human clinical trials as well as physical, scientific, biologic, and engineering tests. The length, complexity, and cost of the approval process may discourage the development of “breakthrough” products, particularly by smaller companies. vision proDucts anD services The ability to see well depends mainly on the shape of the cornea and eyeball (Figure 20-1), the status of the lens of the eye, and the condition of the retina. The common visual problems include: nearsightedness (myoPia) is a condition in which close objects can be seen clearly, but distant ones cannot. farsightedness (hyPeroPia) is a condition in which distant objects are usually seen clearly, but close ones are not brought into proper focus. astigmatism is an irregularity of the front surface (cornea) of the eye, which causes vision to be blurred at all distances. PresbyoPia occurs when the lens of the eye loses its elastic- ity and becomes unable to focus sharply on close objects. This happens gradually as people get older and is usually noticeable in the early- to mid-40s. The change in the lens enables people with a certain amount of nearsightedness to read without glasses, but they will still need glasses for distance vision. Everyone else will need corrective lenses for reading. CataraCts are a clouding of the lens that distorts entering light, causing blurred or hazy vision. Cataracts usually develop slowly. Part Five Other Products and Services422 Figure 20-1. How light rays are focused. With normal vision the rays converge on the retina at the back of the eye (point N). In nearsightedness the eyeball is elongated, causing the rays to focus in front of the retina (point M). In farsightedness the eyeball is too short, and the rays focus behind the retina (point H). Retina Lens Cornea Light source Hm n glauComa is a buildup of excess fluid within the eye, which causes pressure that can damage the optic nerve. Untreated glaucoma can cause blindness. age-related maCular degeneration is an irreversible disorder in which the light-sensing cells in the macula (central zone of the retina) deteriorate, leading to loss of central and detailed vision. The degree of sharpness of visual acuity is expressed as a fraction. The normal value, 20/20, means that the person can see clearly at 20 feet what the average person can see at 20 feet. Someone with 20/100 vision would have to be as close as 20 feet to see what someone with normal vision could see at 100 feet. The legal definition of blindness is vision that cannot be corrected to bet- ter than 20/200. About half the people in America and about 95% of those older than 45 wear glasses or contact lenses. Friedlander and Donev10 note that corrective lenses do not “strengthen” or “weaken” the eyes and do not make the wearer “addicted” to wearing glasses. They also note that people rarely develop headaches because they need glasses, and that the few who do usually are farsighted and went for prolonged periods without wear- ing glasses. Eye-Care Professionals The three main types of professionals involved in vision care are ophthalmologists, optometrists, and opticians. Ophthalmologists are physicians who have complet- ed several years of postgraduate residency training. Un- like optometrists, they can perform surgery and have full prescribing privileges. Some ophthalmologists restrict their practice to the medical and surgical treatment of the eye. Increasing numbers, however, are doing refractions and selling eyeglasses and contact lenses. Optometrists (O.D.s) are trained to examine the eyes and related structures to detect vision problems, eye disease, and other abnormalities. They principally per- form vision examinations for the purpose of prescribing glasses and contact lenses. Optometrists do not perform surgery (except in Oklahoma) but can use drugs to dilate the pupils so they can see the retina better during an eye examination. They are also permitted to use drugs to treat certain eye diseases. Most optometrists are gradu- ates of one of the 20 accredited colleges of optometry in the United States. Admission to these schools requires a minimum of 3 years of undergraduate work, although, as in medicine, few students enter with less than a bac- calaureate degree. Optometry school takes 4 years. A few states require a 6-month internship. All states require passage of written and clinical examinations. In many states, a national board examination may be substituted for the state board examination. Currently there are about 30,000 practicing optometrists in the United States. Opticians are technicians who make and fit eyeglass- es and contact lenses as prescribed by optometrists and ophthalmologists. Opticians do not examine eyes and are not legally authorized to prescribe lenses. They may be trained through apprenticeship or a 2-year community college or vocational school program and are licensed in about half the states. The American Board of Opticianry/ National Contact Lens Examiners offers certification in dispensing opticianry and contact lens–fitting. Licens- ing and board certification may indicate that an optician has had appropriate training, but they do not guarantee this. Chapter Twenty Health Devices 423 Professional Evaluation For people with no known eye problems, the American Optometric Association (AOA)11 recommends examina- tions at age 6 months and 3 years; every 2 years from age 6 through 60; and annually thereafter. This timetable will enable detection of some changes that have not become apparent to the individual, such as the early stages of presbyopia. People with known eye problems may need to be checked more often. The U.S. Preventive Services Task Force (USP- STF)12,13 recommends vision screening for all children at least once between the ages of 3 and 5 years to detect the presence of amblyopia (poor vision in an eye that is otherwise physically normal). However, for other age groups it has concluded that the optimal frequency of screening for visual problems is unknown. A complete eye examination usually takes 30 to 45 minutes and includes:

• A review of the patient’s general health and eye history. The presence of diabetes or high blood pressure is signifi- cant because they can damage retinal blood vessels if not controlled.
• Examination of the outside and inside of the eyes to detect abnormal conditions. A slit lamp is used to check the outer structures and the front of the lens of the eye. An ophthal- moscope is used to check the back of the eye (the retina and part of the optic nerve). Dilating the pupils with drops enables the doctor to see more of the retina.
• Tests to determine eye coordination and eye-muscle function.
• Measurement of the eye’s fluid pressure to check for glaucoma. The American Academy of Ophthalmology14 recommends screening for glaucoma as part of the com- prehensive adult medical eye evaluation, starting at age 20, with the frequency depending on an individual’s age and other risk factors for glaucoma. However, the USPSTF15 is uncertain whether screening does more good than harm.
• Visual acuity testing to determine the ability to see clearly at various distances. An eye chart is used to test distant vi- sion; a printed card is used to test near vision (the ability to read small print).
• Visual field testing to check peripheral vision. The doctor may do this by asking whether you can see the doctor’s fingers as they move to various locations near your head. Mechanized testing is also available.
• Refraction to determine which lenses can correct your vision problem. This is usually done with a phoropter, a device that you look through while the doctor switches lenses to determine which ones enable you to see the best.

The cost of an eye examination depends on the setting and what tests are done. Optometrists tend to charge $50 to $100 for a routine examination; ophthal- mologists generally charge more. Because the cost can vary considerably, it is wise to find out in advance what it will be and how much insurance will cover. Selection of Eyeglasses When an examination determines that glasses are indicated, the doctor prepares a prescription for the appropriate type of lenses. The prescription contains numbers for each eye that represent the lens power and rotation needed to enable the eye to focus for near and distance vision. Many Web sites explain how to interpret prescriptions. Glasses may be purchased from an ophthalmologist, optometrist, optician, or though the Internet. The cost depends on the nature of the lenses, the type of frame, and the vendor’s markup. Some chains have sales during which they offer complete glasses for considerably less. Lenses are classified as single-vision (which focus at only one distance), bifocal (two lenses in one); trifo- cal (three lenses in one); or progressive (multifocal with no obvious dividing line between different portions of the lens).They are made of plastic, glass, or a laminated combination of plastic and glass. Most lenses today are plastic. The FDA requires that all lenses be resistant to shattering on impact. Plastic lenses are more easily scratched but weigh less than glass. Tinting, antiscratch coatings, and anti-glare lenses are available, usually at an extra charge. Tinting is available in many colors, with sunglass tints for outdoor wear. The color can be uniform or can lighten gradually from top to bottom. Photochromatic lenses respond to ultraviolet light, becoming darker in sunlight and lighter in shade. Such lenses take a minute or two to make their changes. They do not work as well in an automobile because sufficient ultraviolet light may not filter through the windows. To select frames, it is also necessary to know the pupillary distance (PD)—the number of millimeters between the pupils of the eyes. Some practitioners will put this on the prescription, but those who sell glasses seldom do so because that enables the buyer to obtain them through the Internet. Most practitioners will dis- close the PD when asked, but there may be an extra fee involved. In 2010 Consumer Reports16 published the results of a survey of about 31,000 of its subscribers who had purchased prescription glasses within the previous 21/2 years. The survey showed (a) readers were more satis- fied when they bought their glasses from independent opticians, private optometrists, and ophthalmologists rather than from large optical chain stores; (b) the median cost at big chains ($155) was lower than the average at independent optical shops ($211) and eye doctors’ offices Part Five Other Products and Services424 ($212); and (c) the chain rating highest in customer satisfaction was Costco. When purchasing locally, it is prudent for glasses to be checked after they have been received from the dispenser to be certain that the pre- scription has been accurately filled. Prescription glasses can be also obtained through Web sites that enable the buyer to choose a frame and insert the relevant prescription numbers into an interac- tive page so lenses can be fitted. Dr. Stephen Barrett has found that Zenni Optical (www.zennioptical.com) sells high-quality prescription glasses for less than 25% of the cost of comparable products at retail outlets, with single- vision glasses as low as $6.95 plus shipping. Placing an order is simple if a previously purchased frame can be used to determine the appropriate dimensions. If not, it may be advisable to purchase one pair locally. Ready-to-wear reading glasses are available in many stores for $10 to $15. These come in different strengths and can be tried out in the store. They may be adequate (though not optimal) for people who are nearsighted or presbyopic and have no astigmatism. They should not be used as a substitute for periodic professional examinations. Contact Lenses Contact lenses are plastic or glass discs worn in front of the pupil and in contact with the cornea. They adhere to the cornea by capillary action on the normal layer of tear fluids. Not everyone can wear them, and they do not correct all vision problems. Except for extreme nearsightedness, vision is no better with contacts than with regular glasses. Many individuals use them for cosmetic reasons, and they also serve a useful purpose in athletics. Modern contact lenses developed after it was un- derstood that the outer covering of the eye (cornea) required a steady supply of oxygen from the air. This led to development of lightweight glass lenses small enough to permit oxygen dissolved in the tears to reach the un- derlying cornea. In the late 1950s a soft plastic lens was created that was flexible, absorbed water, and permitted the cornea to breathe more normally. Extended-wear lenses introduced in the 1970s were more convenient but turned out to cause potentially serious infections if not properly cleaned. The more recently developed gas-permeable lenses permit more oxygen to reach the cornea and are less prone to cause infections. Disposable extended-wear contacts offer the same advantages plus additional convenience. The price charged for contact lenses usually includes the cost of the lenses, the amount of time spent to fit them and to provide follow-up care, the nature of the warranty, and the value of the services as determined by the practitioner. Many sellers guarantee to issue a refund or furnish a pair of glasses if the buyer is unable to adapt to the use of contacts. Hard lenses and gas-permeable lenses are the most economical and durable. Soft lenses are the most com- fortable and can be worn longer, but their care is more difficult. Table 20-1 summarizes the advantages and disadvantages of currently marketed contact lenses. Examinations for prescribing contact lenses are conducted by optometrists and ophthalmologists. They include tests for corneal sensitivity and lacrimal (tear) secretion, a refraction to determine the strength of the lenses, and measurement of the eye’s curvature to de- termine the type of lens needed. The FTC’s Eyeglass Rule requires the eye specialist to give a copy of the prescription to the patient when requested after the examination. Once contact lenses have been purchased, the di- rections for use, maintenance, storage, and cleaning should be followed scrupulously. Serious infections and damage to the eye can result from improper main- tenance and from wearing lenses for longer periods than recommended. Sunglasses Many studies have shown that prolonged exposure to the sun’s rays increases the chances of developing cata- racts, retinal degeneration, cancer of the eyelids, and photokeratitis, a temporary but painful burn of the eye’s surface (sometimes called snow blindness or welder’s flash).17 The sun’s glare can also interfere with comfort and the ability to see clearly. Reducing glare can make driving and outdoor recreational and occupational ac- tivities safer. √ Consumer Tip Shopping for Eyeglasses • Obtain a thorough examination by a competent ophthalmologist or optometrist.

• The Federal Trade Commission (FTC) Eyeglass Rule requires that consumers receive a copy of the pre- scription. This makes it possible to shop to compare prices.
• Wear the glasses for a few days, and have them checked if they do not feel right.
• If the glasses seem defective, do not hesitate to ask the vendor to rectify the problem.

Chapter Twenty Health Devices 425 The AOA says that sunglasses have gone from a fashion accessory to a necessity. There are three main types. Polaroid lenses cut glare and are especially useful when driving or boating. Photochromatic lenses change color with varying light intensity. Mirrored lenses reflect rather than absorb light and are primarily useful when there is intense glare from snow or water. However, they show dirt and are hard to clean. The AOA advises consumers to insist that sunglasses block out at least 99% of ultraviolet radiation; screen out at least 75% of visible light; be perfectly matched in color and free of distortion; and have lenses that are gray (the preferable color), green, or brown.18 Prescription lenses may be advisable for people with vision problems, but clip-on or overfitting sunglasses may be an acceptable substitute. Color can be checked by looking at the glasses against a white background. Distortion can be observed by holding them at arm’s length and looking through them with one eye at something with a rectangular pat- tern. Any distortion will be apparent as the glasses are moved back and forth or rotated. To be sure the lenses block enough light, try them on in front of a mirror. If your eyes are clearly visible through the lenses, the lenses are probably not dark enough for glare reduction and comfort. This test does not apply to photochromatic lenses. Pinhole Glasses Many entrepreneurs have marketed “pyramid” or “pin- hole” glasses consisting of opaque material with multiple slits or perforations. The mechanism involved has been known for centuries and was used before glass lenses were invented. Light passing through a small hole (or holes) is restricted to rays coming straight from the viewed object; these rays do not need focusing to bring them to a point. Modern promoters claim their products are better than conventional lenses. Worrall and others19 state that although both reduce the focus effort needed to read, pinhole glasses are much less useful because they re- strict contrast, brightness, and the field of view. Worn as sunglasses, they can even be harmful because the holes allow damaging ultraviolet rays to reach the eye. Lens Type Rigid gas-permeable (RGP) Made of slightly flexible plas- tics that allow oxygen to pass through to the eyes. Daily wear soft Made of soft, flexible plastics that allow oxygen to pass through to the eyes. Extended-wear Available for overnight wear in soft or RGP lenses. Extended-wear disposable Soft lenses worn for 1 to 6 days and then discarded. Planned replacement Soft daily wear lenses that are replaced on a planned schedule, most often either every 2 weeks, monthly, or quarterly. coMparison oF contact lenses Table 20-1 Source: American Optometric Association.20 Advantages Excellent vision; short adaptation period; comfort- able to wear; correct most vision problems; easy to put on and to care for; durable with a relatively long life; available in tints (for ease in handling and for cosmetic purposes) and bifocals. Very short adaptation period; more comfortable and more difficult to dislodge than RGP lenses; available in tints and bifocals; great for active lifestyles. Can usually be worn up to 7 days without re- moval. Require little or no cleaning; minimal risk of eye infection if wearing instruc tions are followed; available in tints and bifocals; spare lenses available. Require simplified cleaning and disinfection; good for eye health; available in most prescriptions. Disadvantages Require consistent wear to maintain adap- tation; can slip off center of eye more easily than other types. Do not correct all vision problems; vision may not be as sharp as with RGP lenses; require regular office visits for follow-up care; soil easily and must be replaced. Do not correct all vision problems; require regular office visits for follow-up care and monitoring. Vision may not be as sharp as with RGP lenses; do not correct all vision prob- lems; handling may be more difficult. Vision may not be as sharp as with RGP lenses; do not correct all vision prob- lems; handling may be more difficult. Part Five Other Products and Services426 Visual Training “Vision therapists” claim to strengthen eyesight through a series of exercises and the use of eyeglasses. They emphasize exercising hand-eye coordination, watching a series of blinking lights, focusing on a string of objects, and sleeping in a certain position. Some optometrists claim that vision therapy is valuable for children with learning disabilities. The American Academy of Pedi- atrics and several other professional groups have stated that eye exercises and other types of vision therapy have no proven value for learning disabilities.21 Cataract Surgery A cataract is an opacity of the lens of the eye that impairs vision. The cause is unknown, but diabetes and expo- sure to ultraviolet light are important risk factors. Low intake of antioxidants in the diet may also be a factor.22,23 Cataracts can cause double or blurred vision, sensitiv- ity to light and glare, less vivid perception of color, and frequent changes in eyeglass prescription. Cataracts develop in about 400,000 Americans each year, but most remain small and never need treatment. Cataract surgery is the most frequently performed operation on people age 65 or older. More than 1 million cataract extractions are performed each year. During the operation, the lens is removed from its supporting capsule either by pushing it out or by phacoemulsifica- tion (shattering it with ultrasound and sucking out the remnants). A plastic intraocular lens is then placed inside. The procedure takes 20 to 30 minutes and does not re- quire hospitalization. About 95% of patients emerge with better than 20/40 vision with eyeglasses (the minimum required for a driver’s license). Eyeglasses are still needed for reading because the inflexible lens focuses at only one point, usually in the distance. The operations are not risk-free. A small percentage of patients develop swelling or detachment of the retina, glaucoma, infection, or displacement of the intraocular lens. About one-third develop clouding of the lens cap- sule, which can be remedied by cutting a hole through the capsule with a laser. Consumer Reports on Health24 cautions against having the operation unless a cataract hampers daily activities. This usually does not occur un- less a person’s visual acuity drops to 20/50 with glasses. In 2003, the FDA approved the Array multifocal intraocular lens, which, by changing its shape, enables the person to focus on both close and distant objects.25 However, some patients see halos around lights, and one study found that overall user satisfaction was no greater than that with standard intraocular lenses.26 Refractive Surgery It is possible for surgery to permanently alter the refrac- tive state of the eye by either making appropriate corneal incisions or by removing an appropriately shaped disc of corneal tissue. These change the shape of the cornea and enable light rays to converge properly on the retina. Various operations can reduce or correct nearsightedness, farsightedness, and astigmatism. Newer techniques involving computerized as- sessment, precisely calculated tissue removal, and lasers have made refractive surgery more predictable.27 Computerized topography can be used preoperatively to determine the best procedure and postoperatively to determine whether additional correction might be indicated. For people who are severely nearsighted or farsighted or who are experiencing age-related changes in the natural lens of the eye, an alternative approach is replacement of their natural lens with an artificial lens that is more appropriately shaped. The most common type of refractive surgery is laser-assisted in situ keratomileusis (LASIK). In this procedure, a knife called a microkeratome is used to cut a thin, superficial corneal flap, which is folded back. A computer-controlled laser then vaporizes some of the underlying corneal tissue and the flap is replaced.28 Most patients are pleased with the results of their refractive surgery, but complications can occur. Some patients develop glare, halos, and/or double vision that can seriously affect nighttime vision. Undercorrection and overcorrection are relatively common but can usu- ally be corrected by further laser surgery. Dry eye is common but usually lasts only about 2 months. It can be treated by frequent applications of artificial tears and/ A Deluded Physician William Horatio Bates received his M.D. degree from Cornell University in 1885. He was an attending physician at the New York Eye Infirmary and taught ophthalmology at the New York Postgraduate School from 1886 to 1891. In 1920 Dr. Bates wrote Cure of Imperfect Eyesight by Treatment without Glasses. He stated (incorrectly) that the lens of the eye was not a factor in accommodation, and that refractive errors were simply “strain due to an abnormal condition of the mind” that could be helped through various prescribed eye exercises. He also advocated looking directly at the sun for short moments to “strengthen” the eyes. Although his methods have no validity, they are still advocated by a few practitioners today. Staring directly into the sun can seriously damage the retina. Historical Perspective Chapter Twenty Health Devices 427 or by blocking of the pathway through which tears drain from the eye to the nose. Infection is very rare but can be catastrophic. Appropriate preoperative and postoperative antibiotics and the use of sterile precautions reduce the likelihood of infection. People contemplating refractive surgery should discuss the potential benefits and risks with an oph- thalmologist who is well regarded by the medical and optometric communities. Although the procedures have a low incidence of complications, the risk involved may not justify their use if adequate vision can be achieved with eyeglasses or contact lenses. Individuals who wish to have laser surgery should seek someone who is well trained and thoroughly experienced. Regulatory Action The case of the Lasik Vision Institute (LVI) illustrates why careful provider selection is important. LVI has widely advertised LASIK surgery for $299 per eye. About 10 years ago, however, television teams using hidden cameras found that this fee was difficult or impossible to get and that the average price per eye was about $1800. Several investigators concluded that the advertised price was intended to lure patients into consultations at which much higher prices were quoted. LVI was a subsidiary of Musa Holdings, Inc., of Lake Worth, Florida, which also operated Eyeglass World. In 2001, the Florida Attorney General announced that Eyeglass World would pay $500,000 and adopt an arms-length relationship with its affiliated optometrists to settle allegations of unlawful marketing practices. In 2003, LVI signed a consent agreement to settle FTC charges that it had failed to substantiate claims that its LASIK surgery permanently eliminated the need for glasses and contacts, reading glasses, or bifocals. The FTC also charged that LVI had falsely claimed that consumers would receive a free consultation to determine their candidacy for LASIK. Instead, after an initial meeting with an LVI representative, consumers were required to pay a $300 deposit before they were told of the risks associated with the surgery or whether they were eligible candidates.29 Hearing aiDs Hearing loss affects more than 35 million Americans, about half of whom are older than 50. The National Institute on Deafness and Other Communication Dis- orders estimates that only about 20% of people who could benefit from wearing a hearing aid actually wear one.30 The reasons for not using a hearing aid include (a) lack of awareness of problem, (b) cost, (c) not wishing to call attention to disability, (d) dealer practices, (e) sounds when amplified are still not clear, (f) difficulty in manipulating controls, and (g) not knowing where to go for help.31 Hearing loss is most common among the elderly. One person in four older than 65 years and one in three older than 75 years experience this problem. Noise-induced hearing loss is common among young and middle-aged people exposed to high levels of noise from sources such as motorcycles, snowmobiles, powerboats, radios with headphones, poorly designed telephones, live rock band music, and various types of occupational exposure.32 Types of Hearing Loss There are two types of hearing loss: sensorineural and conductive. Sensorineural deafness, also called percep- tive or nerve deafness, is caused by damage to the audi- tory nerve, which connects the inner part of the ear to the brain. Nerve deafness can result from birth defects, illnesses that produce a high fever, overexposure to high noise levels, use of certain medications, head injuries, vascular problems, and tumors. Nerve deafness often is related to aging and is the most common reason for using a hearing aid. In some cases, no cause is apparent. In conductive deafness, which is less common, sound waves cannot be transmitted to the auditory nerve. Conductive deafness is related to the outer and middle portions of the ear and can be caused by (a) impacted wax in the external ear; (b) injury to the eardrum by an explosion, blow to the ear, infection, or sharp imple- ment; or (c) arthritic disease, middle ear infection (otitis media), or another condition that prevents the three tiny bones of the inner ear from vibrating. Some individuals have “mixed” hearing loss—both conductive and sensorineural. Elderly individuals with a hearing loss often have damage to the auditory nerve as well as a defect in the ear mechanism that relays sound to that nerve. Some impairments can be medically or surgically treated. If there is partial hearing, a hearing aid may be effective. People with a hearing loss may find that words are difficult to distinguish; sounds seem muffled or subdued; and high-pitched sounds, such as the ticking of a watch, dripping of a faucet, or high tones of a musical instru- ment, are difficult or impossible to hear. Other signs of possible impairment include asking people to repeat themselves, turning up the volume of a radio or television set, favoring one ear, or straining to hear. Many people with a hearing loss also have tinnitus (continual hissing or ringing of their ears). If a hearing loss is suspected, a physician should be consulted. In most cases an evalu- ation by an otolaryngologist is advisable. Part Five Other Products and Services428 Professional Evaluation An evaluation for suspected hearing loss should include (a) a review of the symptoms and past medical history, (b) examination of the ears and throat, (c) an audiometric test, and (d) other special tests as needed. Audiometry is performed in a soundproof room, usually by an audiolo- gist. Some otolaryngologists employ one in their office, whereas others refer the patient elsewhere. During the test, various tones and levels of sound are transmitted to the patient through an earphone. The patient signals to the tester when sounds are heard, and the tester records the information on a graph (audiogram). The information is analyzed and the hearing level, measured in decibels (dB), is established. When all tests are completed, the otolaryngologist or audiologist informs the patient of the nature and extent of the problem, if any, and whether a hearing aid might be helpful. Some common sounds and their decibel values in- clude: rustling leaves (20 dB), whisper at 5 feet (30 dB), conversational speech at 3 feet (60 dB), loud radio music (65 dB), shouted speech (90 dB), a loud amplified rock band (110 dB), and a jet engine at 100 feet (140 dB). The decibel scale is logarithmic, which means that a jet en- gine is much more than twice as loud as rustling leaves. Hearing loss is also expressed

[TRUNCATED]