Text B. Blood Vessel Disorders

 

Disorders of blood vessels to the eye include bleeding (hemorrhage), inadequate blood supply, and blockage of the vessels. These disorders can have serious consequences, damaging the retina, sometimes permanently, and leading to decreased vision and even blindness. They also indicate that the person is at high risk of other problems, such as stroke.

Diabetic Retinopathy. Diabetes can produce two types of changes that are among the leading causes of blindness—nonproliferative and proliferative retinopathy. These changes can occur in diabetics who take insulin and those who don't.

Diabetes affects the retina because high blood sugar (glucose) levels make the walls of small blood vessels thicker but weaker and therefore more prone to deformity and leakage. The extent of retinopathy and vision loss is related to how well blood sugar levels are controlled and, more important, how long the person has had diabetes. In general, retinopathy doesn't develop until at least 10 years after a person becomes diabetic.

In nonproliferative (background) retinopathy, small capillaries in the retina break and leak. The area around each break in the capillaries swells, forming small pouches in which blood proteins are deposited. A doctor diagnoses this condition by examining the retina. Fluorescein angiography—a procedure in which a doctor injects dye into a vein, waits for it to reach the retina, and then photographs the retina—helps determine the extent of the condition. In its early stages, nonproliferative retinopathy doesn't cause blindness. Small retinal hemorrhages may distort parts of the field of vision, or if they're near the macula, may blur vision.

In proliferative retinopathy, damage to the retina stimulates the growth of new blood vessels. Such growth may seem beneficial, but it isn't. The new blood vessels grow abnormally, leading to scarring and sometimes to retinal detachment. They may grow or bleed into the vitreous cavity. Proliferative retinopathy is much more damaging to the vision than nonproliferative retinopathy and can lead to total or nearly total blindness.

Prevention and Treatment

The best way to prevent diabetic retinopathy is to control diabetes and keep blood pressure at normal levels. People with diabetes should have annual eye examinations starting 5 years after diabetes is diagnosed, so that any necessary treatment can be started early and vision may be saved.

Treatment consists of laser photocoagulation, in which a laser beam is aimed through the eye to destroy the new blood vessels and seal off leaking ones. This treatment is painless because the retina doesn't sense pain. If bleeding from damaged vessels has been extensive, surgery to remove the blood that leaked into the vitreous humor (a pro­cedure called a vitrectomy) may be needed. Vi­sion improves after the vitrectomy, and the vit­reous humor is gradually replaced.

Notes:

pouch	мешок, углубление
blur	расплывшееся пятно; неясные очертания
vitreous cavity	стекловидная полость
laser beam	лазерный пучок
vitreous humor	стекловидное тело

 

Glaucoma

Text.

Glaucoma is a disorder in which the pressure in the eyeball increases, damaging the optic nerve and causing a loss of vision.

Both the front (anterior) and back (posterior) chambers of the eye are filled with a thin fluid called the aqueous humor. Normally, the fluid is produced in the back (posterior) chamber, passes through the pupil into the front (anterior) chamber, and then drains from the eye through the outflow channels. If the flow of fluid is interrupted, usually by an obstruction that prevents the fluid from flowing out of the anterior chamber, pressure increases.

Usually, glaucoma has no known cause; however, it sometimes runs in families. If the outflow channels are open, the disorder is called open-angle glaucoma. If the channels are blocked by the iris, the disorder is called closed-angle glaucoma.

An ophthalmologist or optometrist can measure the pressure in the anterior chamber, called intraocular pressure or tension, by using a simple, painless procedure called tonometry. In general, measurements greater than 20 to 22 millimeters indicate increased pressure. Occasionally, glaucoma occurs when pressures are normal. Sometimes a series of measurements must be taken over time to determine that the problem is glaucoma. An examination with an ophthalmoscope (an instrument used to view the inside of the eye) may reveal visible changes in the optic nerve caused by glaucoma. Sometimes, the examiner uses a special lens to observe the outflow channels; this procedure is known as gonioscopy.

Glaucoma produces a loss of peripheral vision or blind spots in the visual field. To find out if such blind spots exist, an examiner asks the person to look straight ahead at a central point and indicate when light can be seen. The test may be done either using a screen and pointer or an au­tomated device that uses spots of light.

In open-angle glaucoma, fluid drains too slowly from the anterior chamber. Pressure gradually rises—almost always in both eyes—causing optic nerve damage and a slow, progressive loss of vision. Vision loss begins at the edges of the visual field and, if not treated, eventually spreads to all parts of the visual field, ultimately causing blindness.

The most prevalent form of glaucoma, open-angle glaucoma is common after age 35 but occasionally occurs in children. The condition tends to run in families and is most common in people with diabetes or nearsightedness (myopia). Open-angle glaucoma develops more often and may be more severe in blacks than in whites.

Symptoms and Diagnosis

Initially, increased pressure in the eyes produces no symptoms. Later symptoms may include narrowing peripheral vision, mild headaches, and vague visual disturbances, such as seeing halos around electric lights or having difficulty adapting to darkness. Eventually, tunnel vision (an extreme narrowing of the visual fields that makes it difficult to see anything on either side when looking straight ahead) may develop.

Open-angle glaucoma may not cause any symptoms until irreversible damage has developed. Usually, the diagnosis is made by checking intraocular pressure. Therefore, every routine eye examination should include a test of intraocular pressure.

Treatment

Treatment is more likely to be successful if started early. Once vision is greatly impaired, treatment may prevent further deterioration, but it usually can't restore vision completely.

Medicated eyedrops can usually control open-angle glaucoma. Typically, the first eyedrop medication prescribed is a beta-blocker—such as timolol, betaxolol, carteolol, levobunolol, or metipranolol—which probably decreases the production of fluid in the eye. Pilocarpine, which constricts the pupils and increases drainage from the anterior chamber, is also helpful. Other useful medications—such as epinephrine, dipivefrini and carbachol—work either by improving out flow or decreasing fluid production. A carbonic anhydrase inhibitor, such as acetazolamide, can be taken by mouth, or dorzolamide can be used as eyedrops.

If medication can't control eye pressure or if side effects are intolerable, an eye surgeon can increase drainage from the anterior chamber by using laser therapy to create a hole in the iris or using surgery to cut out part of the iris.

Secondary glaucoma occurs because the eye has been damaged by an infection, inflammation, tumor, an enlarged cataract, or any eye disorder that interferes with fluid drainage from the anterior chamber. Inflammatory diseases, such as uveitis, are among the most common of these disorders. Other common causes include ophthalmic vein blockage, eye injury, eye surgery, and bleeding into the eye. Some medications, such as corticosteroids, can also increase pressure in the eye.

Treatment of secondary glaucoma depends on the cause. For example, when the cause is inflammation, corticosteroids are often used to decrease the inflammation along with medications that keep the pupils large. Sometimes surgery is necessary.

 

Notes:

open-angle glaucoma	открытоугольная глаукома, простая глаукома
closed-angle glaucoma	закрытоугольная глаукома
vague	неопределенный, неясный
deterioration	ухудшение

 

EXERCISES

 

Exercise 1. Make up sentences of your own using the following words and phrases from the texts to Section “Eyes and Vision”.

 

blindness, to be linked with, possible risk factors, the reason for surgery, to be associated with, a high risk, to consider, to examine somebody for, multiple causes, eyesight, to protect, the inner surface, the clarity of vision, to treat cataracts, regular eye examination, contact lenses, to be sterilized and disinfected, to correct nearsightedness and farsightedness, to be risk free, to make vision blurry, internal bleeding in the eye, to depend on the depth of the burn, to put pressure on the eye, to lead to blindness, to play a key role in protecting the eyes, to produce pain and itching, to be taken orally, sensitivity to light.

 

Exercise 2. Study the text “Glaucoma” and say whether these statements are right or wrong. Correct them if they are wrong.

 

Glaucoma is a disorder in which the pressure in the eyeball decreases, damaging the optic nerve and causing a loss of vision.

Normally, the fluid is produced in the front (anterior) chamber, passes through the pupil into the back (posterior) chamber, and then drains from the eye through the outflow channels.

Glaucoma sometimes runs in families.

Occasionally, glaucoma occurs when pressures are normal.

Glaucoma produces a progressive, painless loss of vision.

Secondary glaucoma develops more often and may be more severe in blacks than in whites.

Later symptoms of glaucoma may include norrowing peripheral vision, mild headaches, and vague visual disturbances.

Open-angle glaucoma may not cause any symptoms until irreversible damage has developed.

Open-angle glaucoma occurs because the eye has been damaged by an infection, inflammation, tumor or any eye disorder.

Other common causes of secondary glaucoma include ophthalmic vein blockage, eye injury, eye surgery, and bleeding into the eye.

 

Exercise 3. Choose the correct answer.

1. When a patient refers to the white of the eye he means

a) the sclera c) the cornea

b) the lens d) the fovea

 

2. The lacrimal gland produces

a) lactase c) mucus

b) tears d) spit

 

3. The yellow spot is

a) the pupil c) the fovea

b) the choroids d) the optic nerve

 

4. The eye photoreceptors are

a) rods and cones c) iris

b) optic nerve d) visual cortex

 

5. To blink is to

a) respond to dim light c) to contract the lateral rectus

b) to lower the eyelid d) to activate the lacrimal glands

 

 

Exercise 4. Learn the definition of the following special terms.

 

diagnosis – the use of scientific methods to determine the cause and nature of a patient’s illness.

 

examination – careful study of the patient body to determine the presence or absence of disease or abnormality.

 

ophthalmologist – a specialist who provides comprehensive eye and vision care, both medical and surgical.

 

cataract – an abnormal progressive condition of the lens of the eye, characterized by loss of transparency. It may be congenital, senile, traumatic or due to diabetes.

 

conjunctiva – the mucous membrane lining the inner surfaces of the eyelids and anterior part of the sclera.

 

conjunctivitis – an inflammation of the conjunctiva, caused by bacterial or viral infection, allergy or environmental factors. Also called pinkeye.

 

mystagmus – rapidly jerking movement of the eye from side to side.

 

scotoma – area of depressed vision surrounded by an area of normal vision.

 

Exercise 5. Discuss the meaning of the following special terms.

 

legal blindness, refractive surgery, keratotomy, orbital cellulites, exophtalmos, dacryostenosis, blepharitis, trachoma, keratitis, retinopathy, glaucoma, myopia.

 

Exercise 6. Answer the following questions to the texts from Section “Eyes and Vision”

 

1. What is glaucoma? What types of glaucoma do you know?

2. What is cataract? What types of cataract do you know? What age suffers cataract?

3. What does the term legal blindness mean?

4. What causes blindness?

5. How are refractive errors treated?

6. When is surgery administered to cataract patients?

7. What are the most common symptoms of conjunctivitis? What types of conjunctivitis do you known?

8. What medicine is used to prevent trachoma?

9. What is the difference between Herpes Simplex Infection and Herpes Zoster Infection?

10. Who is more susceptible to glaucoma (cataract)?

11. What may be done in case of astigmatism?

12. What are the most common eye injuries?

13. What is used to remove foreign objects in the eye?

14. What procedures may help correct nearsightedness, farsightedness and astigmatism?

 

Exercise 7. Match the half-sentences in column A with the half-sentences in column B to make correct and complete sentences.

 

A

1. The eye constantly produces…

2. The structures around the eye protect it…

3. The eyelids reflexively close quickly to protect…

4. The lacrimal glands produce…

5. Disorders of the nervous system can damage…

6. The areas of the brain that interpret visual impulses may be…

7. An imperfectly shaped cornea may…

8. Refractive errors can…

9. Most contact lenses must…

10. If a person experiences discomfort, excessive tearing, or eye redness, the lenses…

11. The best candidates for refractive surgery are…

12. Any injury to the eye should be examined by a doctor…

13. Damage to the inside of the eye is…

14. An injury affecting the tear ducts…

15. Often the foreign object can…

16. Chemical burns can…

17. Severe burns may…

18. An injury to the face can…

19. The extent of the protrusion can…

20. The eyelids provide…

 

B

a) …be measured with an ordinary ruler or with an exophtalmomemeter.

b) …fracture any of several bones that form the orbits

c) …occur when an irritating substance gets into the eye.

d) …a mechanical barrier against injury, closing reflexively when an object comes too close to the eye.

e) …to determine whether treatment is needed and whether the eyesight may be affected permanently.

f) …need to be treated by an ophthalmologist to preserve vision and prevent major complications.

g) …continuous images that are instantly transmitted to the brain.

h) …be lifted out with a moist sterile cotton swab.

i) …while allowing it to move freely in all directions.

j) …the optic nerve, which carries impulses to the brain.

k) …the eye from foreign objects, wind, dust, and very bright light.

l) …the watery portion of tears.

m) …cause visual distortion from astigmatism.

n) …people whose vision can’t be corrected by eye-glasses or contact lenses.

o) …damaged by stroke, tumor, or other disease.

p) …should be removed immediately.

q) …be corrected with glass or plastic lenses.

r) …often more serious than to the surface.

s) …be removed and cleaned every day.

t) …should be repaired by an eye surgeon.

 

Exercise 8. Underline the correct word or phrase to complete each sentence.

 

1. The orbits are bony cavities containing a) the eyeballs, muscles, nerve, blood vessels, fat and structures that produce and drain tears; b) the nerves that sence light and the blood supply that nourishes them.

2. The inner surface of the eyelid is a) a thick membrane that loops back to cover the surface of the eye; b) a thin membrane that loops back to cover the surface of the eye.

3. Recurring bleeding and increased pressure within the eye may lead to a) blindness, infection of the brain and spinal cord, and blood clots in the brain; b) blood staining of the cornea, which can reduce vision much as a cataract does.

4. Orbital cellulites is a) an infection of the tissues around the eyeball; b) the blockage of a large vein at the base of the brain, caused by an infection around the nose.

5. Exophthalmos can occur a) with eyelid inflammation include staphylococcal infection; b) suddenly from bleeding behind the eye or from inflammation in the eye socket.

6. Inflammation of the eyelids causes a) redness and thickening; b) lid edema.

7. Herpes zoster is a) a bacterial infection, causing ulceration, permanent scarring, and a loss of feeling when the eye is touched; b) a virus that grows in nerves and may spread to the skin, causing shingles.

8. A cataract is a) cloudiness in the eye’s lens that impairs vision; b) a condition in which the macula, the central and most vital area of the retina degenerates.

 

Exercise 9. Match the medical term of the eye disorders A with its proper definition B.

A

1. nystagmus; 2. amblyopia; 3. cataract; 4. hyperopia; 5. esotropic; 6. myopic; 7. presboypia; 8. extropia 9. astigmatism;

10. glaucoma; 11. macular degeneration; 12. retinitis pigmentosa;

13. strabismus; 14. scotoma; 15. hemianopsia.

 

B

1. any abnormal deviation of the eye; squint; 2. nearsightedness; eyeball is too long; 3. turning inward of eye; 4. defective vision or blindness in half of the visual field; 5. abnormal curvature of the cornea, leading to blurred vision; 6. lens clouds over with opaque film and vision is impaired; 7. blockage of circulation of aqueous humor leads to increased intraocular pressure; 8. quick, jerky movement of the eye from side to side; 9. farsightedness; eyeball is too short; 10. dull, dim vision; 11. tendency of the eye to turn outward; 12 defect of vision of old age due to loss of elasticity of the lens; 13 blind spot; area of depressed vision surrounded by an area of less depressed or normal vision; 14. progressive sclerosis; pigmentation and atrophy of the inner lining of the eye; 15. deterioration of the macula lutea of the retina.

 

Exercise 10. Speak on the following.

1. Eye Injuries.

2. Conjuctivitis. Symptoms and Treatment.

3. Cataracts. How Cataracts Affect Vision.

4. Glaucoma. Different Types of Glaucoma.