Selection 2: Protecting Vision and Hearing
(biology)

Many young adults who spend too much time in the sun without protecting their eyes end up with poor vision later in life. Many young adults damage their hearing so gradually that they are not aware of it until it is too late. In the selection below, you will learn about common causes of vision and hearing loss and ways you can minimize your risks of both types of damage. In the following selection, you will encounter some special terms that refer to parts and disorders of the eye and ear. They may be new to you, but they should not keep you from understanding the points the author is making about steps you can take to prevent vision and hearing loss.

Age can be accompanied by a serious loss of vision and hearing. The time to start preventive measures for such problems, however, is when we are younger.

Preventing a Loss of Vision

1. The eye is subject to both injuries and disorders. Although flying objects sometimes penetrate the cornea and damage the iris, lens, or retina, careless use of contact lenses is the most common cause of injuries to the eye. Injuries cause only 4% of all cases of blindness; the most frequent causes are retinal disorders, glaucoma, and cataracts, in that order. Retinal disorders are varied. In diabetic retinopathy, which blinds many people between the ages of 20 and 74, capillaries to the retina burst, and blood spills into the vitreous humor Careful regulation of blood glucose levels in these patients may be protective. In macular degeneration, the cones are destroyed because thickened choroid vessels no longer function as they should. Glaucoma occurs when the drainage system of the eyes fails, so that fluid builds up and destroys nerve fibers responsible for peripheral vision. Eye doctors always check for glaucoma, but it is advisable to be aware of the disorder in case it comes on quickly. Those wo have experienced acute glaucoma report that the eyeball feels as heavy as a stone. In cataracts, cloudy spots on the lens of the eye eventually pervade the whole lens. The milky yellow-white lens scatters incoming light and blocks vision.
2. There are preventive measures that we can take to reduce the chance of defective vision as we age. Accumulating evidence suggests that both macular degeneration and cataracts, which tend to occur in the elderly, are caused by long-term exposure to the ultraviolet rays of the sun. It is recommended, therefore, that everyone, especially those who live in sunny climates or work outdoors, wear glass, not plastic, sunglasses to absorb ultraviolet light. Large lenses worn close to the eyes offer further protection. Special purpose lenses that block at least 99% of UV-B and 60% of UV-A, and 20-97% of visible light are good for bright sun combined with sand, snow, or water. Healthcare providers have found an increased incidence of cataracts in heavy cigarette smokers. In men, smoking 20 cigarettes or more a day, and in women, smoking more than 35 cigarettes a day doubles the risk of cataracts. It is possible that smoking reduces the delivery of blood and therefore nutrients to the lens.

Preventing a Loss of Hearing

3. Especially when we are young, the middle ear is subject to infections that can lead to hearing impairment if they are not treated promptly by a physician. The mobility of ossicles (the stirrup, hammer, and anvil, which are the three small bones in the middle ear) decreases with age, and in the condition called otosclerosis, new filamentous bone grows over the stirrup, impeding its movement. Surgical treatment is the only remedy for this type of conduction deafness. However, age associated nerve deafness due to stereocilia damage from exposure to loud noises is preventable. Hospitals are now aware that even the ears of the newborn need to be protected from noise and are taking steps to make sure neonatal intensive care units and nurseries are as quiet as possible.
4. In today's society, exposure to excessive noise is often possible. Noise is measured in decibels, and any noise above a level of 80 decibels could result in damage to the hair cells of the spiral organ (organ of Corti). Eventually, the stereocilia and then the hair cells disappear completely. If listening to city traffic for extended periods can damage hearing, it stands to reason that frequent attendance at rock concerts, constantly playing a stereo loudly and using earphones at high volume are also damaging to hearing. The first hint of danger could be temporary hearing loss, a "full" feeling in the ears, muffled hearing, or tinnitus (e.g., ringing in the ears). If you have any of these symptoms, modify your listening habits immediately to prevent further damage. If exposure to noise is unavoidable, specially designed noise reduction earmuffs are available, and it is also possible to purchase earplugs made from a compressible, spongelike material at the drugstore or sporting-goods store. These earplugs are not the same as those worn for swimming, and they should not be used interchangeably.
5. Aside from loud music, noisy indoor and outdoor equipment, such as a rugcleaning machine or a chain saw, are also troublesome. Even motorcycles and recreational vehicles such as snowmobiles and motocross bikes can contribute to a gradual loss of hearing. Exposure to intense sounds of short duration, such as a burst of gunfire, can result in an immediate hearing loss. Hunters may have a significant hearing reduction in the ear opposite the shoulder on which the gun is carried. The butt of the rifle offers some protection to the ear nearest the gun when it is shot.
6. Finally, people need to be aware that some medicines are ototoxic (damaging to hearing and balance). Anticancer drugs, most notably cisplatin, and certain antibiotics (e.g., streptomycin, kanamycin, gentamicin) make the ears especially susceptible to hearing loss. Anyone taking such medications needs to be especially careful to protect his or her ears from any loud noises.

Source: Sylvia Mader, Biology, 8th ed., New York: The McGraw-Hill Companies, Inc., 2004, p. 727.

Directions: Questions 1-5 are objective questions that are based on the information in the selection. Answer them by clicking on the correct answer. You may refer to the selection as you answer the questions.

1	The most common cause of eye injuries is
	A)	sharp objects.
	B)	careless use of contact lenses.
	C)	work-related injuries.
	D)	failure to use protective eyewear.
2	The majority of cases of blindness result from
	A)	retinal disorders, glaucoma, and cataracts.
	B)	diabetic retinopathy and eye injuries.
	C)	macular degeneration and glaucoma.
	D)	eye injuries.
3	The risk of developing macular degeneration and cataracts can be reduced by
	A)	improving drainage in the eyes so that fluid does not build up.
	B)	not wearing contact lenses.
	C)	having regular eye exams and monitoring blood glucose levels.
	D)	wearing sunglasses that absorb ultraviolet rays and by not smoking.
4	Constant exposure to noise from which of the following sources could lead to hearing loss or deafness?
	A)	city traffic
	B)	earphones at high volume
	C)	snowmobiles
	D)	all of the above
5	People who are taking certain anticancer drugs and antibiotics should
	A)	take extra measures to avoid exposure to loud noises while taking those medicines.
	B)	have their hearing tested after the cancer treatment has been completed.
	C)	wear noise reduction earmuffs or earplugs for the rest of their lives.
	D)	not go swimming without earplugs.

Directions: Questions 6-10 give you the opportunity to use context clues to deduce the meaning of certain words from the selection. The first sentence for each item comes from the selection and contains a vocabulary word, which appears in italics. The second sentence is not from the selection, but it uses the vocabulary word in the same sense as in the first sentence, and it contains additional context clues. Answer each question by clicking on the answer choice that makes sense in both sentences.

6	"Although flying objects sometimes penetrate the cornea and damage the iris, lens, or retina, careless use of contact lenses is the most common cause of injuries to the eye." The nail I stepped on went through my shoe; fortunately, it was not long enough to penetrate my foot. penetrate
	A)	hurt
	B)	damage
	C)	discolor
	D)	pass into
7	"Those who have experienced acute glaucoma report that the eyeball feels as heavy as a stone." When my grandmother's pneumonia became more acute, her doctor moved her to the hospital's intensive care unit. acute
	A)	severe
	B)	noticeable
	C)	contagious
	D)	persisten
8	"Glaucoma occurs when the drainage system of the eye fails, so that fluid builds up and destroys the nerve fibers responsible for peripheral vision." Because drivers' peripheral vision is limited when the car is in motion, drivers should constantly check the side mirrors to monitor the traffic. peripheral
	A)	related to the evening or night
	B)	related to bright light
	C)	related to the outer part of the field of vision
	D)	related to opaqueness or cloudiness
9	"In cataracts, cloudy spots on the lens of the eye eventually pervade the whole lens." As the number of cases of the unidentified viral disease spread, fear began to pervade the country. pervade
	A)	infect
	B)	spread throughout
	C)	scar; leave marks on
	D)	damage
10	"Especially when we are young, the middle ear is subject to infections that can lead to hearing impairment." Chronic stress can lead to impairment of the immune system. impairment
	A)	condition of being damaged or diminished
	B)	condition of being strengthened or improved
	C)	state of constant change
	D)	state of complete loss

Applied Reading Skills Questions

Directions: Questions 11-15 test your ability to apply certain reading skills. Answer each question by clicking on the correct answer. You may refer to the selection as you answer the questions.

11	The pattern used to organize the information in paragraph 6 of the selection is
	A)	list.
	B)	sequence.
	C)	cause-effect.
	D)	comparison.
12	The author's primary purpose for writing this selection is
	A)	to instruct readers about how to protect their vision and hearing.
	B)	to convince readers to wear protective vision and hearing devices.
	C)	to encourage readers to have regular vision and hearing exams.
	D)	to describe the extent to which people in this country are affected by vision and hearing problems.
13	Based on information in the selection, it can be logically inferred that
	A)	significant deterioration of vision and hearing are inevitable a people age.
	B)	people should wear plastic sunglasses that contain special UV-light protection.
	C)	there are several obvious things people can do to reduce their risk of vision and hearing loss.
	D)	all cancer patients experience some degree of hearing loss.
14	Snowmobiles, motorcycles, chain saws, and rugcleaning machines are given as examples of equipment that can cause
	A)	retinal damage.
	B)	sudden hearing loss.
	C)	gradual hearing loss.
	D)	ototoxic damage.
15	One assumption the author makes is that
	A)	people do not care about vision and hearing loss until these losses become a reality.
	B)	vision and hearing loss cannot be prevented.
	C)	people face a greater likelihood of vision problems than hearing problems.
	D)	if people know steps to take to prevent vision and hearing loss, they will follow them.