Ординатура / Офтальмология / Английские материалы / The Eye Care Sourcebook_Lavine_2001

T H E E Y E C A R E S O U R C E B O O K

spots to appear (the tear breakup time). Normally, there should be no dry spots for at least ten to fifteen seconds. Symptoms with this type of dry eye syndrome can be similar to those seen with aqueous deficiency. Blurring can occur soon after you begin to read. That’s because you have a bit of a stare when you read, and you blink only about half as often as you normally do. That gives the dry spots much more time to form. Some people also blink less often when they drive, so the blurring can occur with driving as well. A common cause of an unstable tear film is a malfunctioning of the oil glands of the eyelids. (See “Blepharitis,” page 59.) The excess oil can create a chemical imbalance in the tear film, rendering it unstable. Some skin diseases that also affect the eye can destroy some of the mucous glands in the eyelids, and the lack of mucin can destabilize the tear film. Vitamin A deficiency can also do this. Although not common in the United States, vitamin A deficiency occurs in people who eat primarily grains and beans, as they lack the beta-carotene that the body converts to vitamin A.

Treating Dry Eye Syndrome

Treatment depends on the type and severity of dry eye syndrome. It is helpful to avoid exposing the eyes to wind or air coming in through the windows or the vents in a car. Eyeglasses can help protect the eyes from wind and lessen the amount of tear evaporation. Using glasses with side shields is even more effective. If you are able to choose where to live, try to avoid hot, dry climates.

Artificial tear drops are over-the-counter eyedrops that have been designed to replace the eye’s natural tears. Even if you know the type of dry eye syndrome you have, it is impossible to know for sure which brand of artificial tear will work best for you. Therefore, it’s best to

try all of them and see which one feels best and provides the best vision and comfort. Unfortunately, their effect on the eye is fairly short lived. People who need to instill the drops more than two or three times a day

should use preservative-free artificial tear drops. The chemical preservatives in regular artificial tear drops can irritate the eyes with frequent use. People who experience blurring with reading because of an unstable tear film may have to use the drops as often as every fifteen minutes while reading.

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Over-the-counter ointments represent another form of eye lubrication. The main drawback with ointments is that they blur your vision, so they are generally used only at bedtime. Mineral oil and petrolatum are the usual ingredients, but some lubricating eye ointments also contain lanolin. Lanolin comes from sheep’s wool and can contain the pesticides that are sprayed on the sheep. These pesticide residues can irritate the eyes, so be aware of that potential problem.

Another lubrication option is Lacrisert. Lacrisert can be thought of as an artificial tear in solid form. It’s a thin little pellet that you insert between your lower eyelid and your eye with the help of a flexible applicator. Insertion requires a little dexterity, but this can often be achieved with practice. The pellet can be inserted once or twice a day, and it gradually dissolves, slowly releasing the artificial tear substance. Sometimes people, especially those with very dry eyes, report a little irritation and a feeling

of something in the eye after they insert the Lacrisert. One reason is that an extremely dry eye may not have enough moisture of its own to begin the process of dissolving the Lacrisert,

so it remains hard. One solution is to instill a few artificial tear drops after the Lacrisert is inserted. That is often enough to soften it and make it more comfortable.

Extremely dry eyes sometimes require more extreme measures. The openings (puncta) to the two tiny drainage canals (canaliculi) near the inner corner of the eye that allow tears to drain out of the eye can be sealed shut, either temporarily with tiny plugs or permanently by burning them shut with a thin wire cautery.

The results are often dramatic. People with red, painful eyes often find that their eyes have become white and comfortable within twenty-four hours. They feel so much better that they don’t usually even notice any discomfort caused by the cautery. For eyes that are not so dry, however, there is the risk of developing a tear overflow problem.

Another temporary measure is using a moist chamber, a kind of inexpensive, close-fitting goggle that keeps the tears from evaporating.

Dry eye syndrome is a chronic condition, but new and improved treatments over the years have made it manageable for most people. Hopefully, we will soon find ways of treating the cause or even preventing the problem.

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Lacrimal Problems

Lacrimal problems include disorders of the main tear gland (lacrimal gland) and the tear drainage system. The lacrimal gland lies behind the upper eyelid over the outside part of each eye. The tear drainage system includes the puncta, the two tiny openings in the margins of the upper and lower eyelids toward the inner corner of the eye; the canaliculi, the thin tubes that carry tears from the puncta to the tear sac (lacrimal sac) located in a little bony depression alongside the nose; the tear sac itself; and the tear duct (nasolacrimal duct), which carries tears from the tear sac into the interior of the nose.

Infant Tear Duct Problems

Infants are sometimes born with congenital dacryostenosis, a condition in which the opening of the tear duct into the nose is partially closed off. Most of the time, it has opened up before birth. However, if it remains shut, the tears cannot drain normally out of the eye, and the eye wells up with tears, which may even overflow and run down the cheek. This may occur in just one eye or in both. Because of the blockage, infection in the tear sac often occurs. Pus from the tear sac frequently moves backward through the canaliculi and out the puncta into the eye, which may become intermittently red from the mild infection.

Treating Congenital Dacryostenosis Treatment of congenital dacryostenosis should begin as soon as it is diagnosed. The mainstay of treatment is massage of the tear sac. With one finger, apply moderate pressure on the skin over the tear sac, located between the inner corner of the eye and the nose. As you press, pus may be expressed backward into

the eye. As you continue pressing, slide the finger in a downward direction between the nose and the cheek. You are attempting to

force the contents of the tear sac in a downward direction, which increases the pressure in the tear duct and hopefully encourages it to open up so that drainage into the nose occurs. You may repeat the process two or three times. If a mild antibiotic eyedrop has been prescribed for infection, instill it in the eye after completing the massage. Perform this whole procedure four times a day or as your doctor prescribes.

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If Congenital Dacryostenosis Doesn’t Get Better With time, most cases of congenital dacryostenosis resolve, although it could take months or even a year. If it does not get better on its own, a tear duct probing can be performed. In this procedure, the punctum of the upper lid (preferably) is dilated with thin, wirelike probes. A probe is then introduced into the punctum, advanced along the canaliculus until it enters the tear sac, and then threaded down the tear sac until it encounters the obstruction where it should be entering the interior of the nose. After a little pressure is applied with the probe, a little “popping” sensation is felt, and the probe enters the interior of the nose. This usually cures the problem. The timing of probing remains controversial. It can be done at two or three months of age without the use of anesthesia. However, some people claim that there might be an element of suffering for the infant. If one waits until the infant is over six months old, though, and has more difficulty keeping still, the procedure must be done under general anesthesia in the operating room, which entails a tiny

degree of risk. It is even possible to wait until the infant is a year of age or more before resorting to the probing, but the chance of success declines in children over one year old.

An unsuccessful probing can be repeated at a later date, but ultimately a more complicated procedure or even surgery may be necessary. So when to do the probing? I generally recommend doing it at one year of age if the problem has not resolved by then.

Adult Tear Duct Problems

The hallmark of a narrowing or obstruction of the tear duct in adults is epiphora, the medical term for tears running down the cheek. If people have an excess in tear production—for example, in an irritated eye—the tears generally do not run down the cheek if the tear duct is functioning normally. Adults may also get infections in the tear sac, just as infants do. The cause of the problem is different in adults, however. Although in rare cases a tumor may be causing the obstruction, most of the time we are simply dealing with a somewhat narrow tear duct whose lining has become swollen as the result of some irritation.

Evaluating Adult Tear Duct Problems When someone has a tearing problem, we often introduce a very thin probe into both the upper and lower canaliculi

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to make sure no obstruction is there. If the canaliculi are open and the lids hug the eyes as they should, then we know that tears can get to the tear sac and that the problem is with the tear duct. What we can do at this point is prescribe an eyedrop that combines a sulfa drug or antibiotic (to fight infection) with a cortisone component (to combat inflammation). Such a drop might be used four times a day for two weeks. If the tearing problem goes away, then we taper off the drops and see whether the problem returns. If, however, the tearing problem is persistent, then further testing needs to be done.

In borderline cases in which we’re not sure that there really is a tear duct problem, we might perform a five-minute dye disappearance test. In this test, a drop of a solution containing the yellow dye fluorescein is instilled in both eyes. After five minutes, we see how much of the fluorescein remains in each eye. An abnormal test result does not prove that there is a tear duct problem, however. For example, aging eyelids that do not hug the eye closely may not allow the tears to enter the puncta very well, thereby causing tears to well up in the eyes.

A more definitive test is called the Jones test. In the first part of this test, a fluorescein eyedrop is instilled in the eye as with the dye disappearance test. However, rather than just seeing how much dye remains in each eye after a few minutes, we advance a thin probe with some cotton wrapped around the tip into the nose in the area where the tear duct empties into the nose’s interior. We then remove the probe and see whether the cotton has been stained with the fluorescein dye. If so, that is a normal result. If no dye is recovered in this way, we proceed with the second part of the Jones test. We irrigate the lower canaliculus with salt water, forcing the water into the tear sac and down the tear duct. If the yellow dye that had reached the tear sac is then recovered in the nose, we know that a partial obstruction or severe narrowing of the tear duct is present, and this is what we find in the majority of cases. However, if no dye is recovered in the nose, then either the tears are not reaching the tear sac (as with an eyelid problem or an obstruction of the canaliculi) or the tear duct may be completely obstructed. Once obstruction of the tear duct has been diagnosed, special X-ray tests may be done if there is any suspicion of a tumor or of any other abnormalities.

Treating a Tear Duct Obstruction The definitive treatment for tear duct obstruction is an operation called a dacryocystorhinostomy, or DCR. An incision is made alongside the nose in the area of the tear sac. A hole is drilled

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through the bone on the side of the nose, and a direct communication is made between the tear sac and the inside of the nose. The tear duct is thereby bypassed, and the procedure is successful over 90 percent of the time. If the canaliculi rather than the tear duct are blocked, however, then not only is a standard DCR performed, but a glass tube called a Jones tube is inserted through the eyelid tissue at its inner corner, with one end of the tube facing the eye and the other end traversing the hole in the bone and entering the interior of the nose. One must take care of the tube afterward to make sure it does not become plugged up.

Tearing as a Symptom

Tearing is a very common symptom. An eye infection, a scratch on the eye, or a foreign body in the eye will stimulate tearing. Even dry eye syndrome can paradoxically result in tearing, with the irritation caused by the dryness occasionally stimulating the tear gland to put out a spurt of tears. Tearing is especially common in elderly individuals. There may be many contributing factors. Dry eye syndrome along with a chronic blepharitis may be present. Aging changes in the eyelids may cause ectropion, a turning outward of the lid margin that denies the tears access to the lower punctum of the eyelid, where the tears enter the drainage system. Entropion, a turning inward of the lid margin, may be present, causing irritation of the eye. In some people, the tear duct may be somewhat narrower than in others. How, then, do we deal with a tearing problem in the older person?

Clearly, if there is some irritating factor, such as blepharitis, it should be treated. (See “Blepharitis,” page 59.) Tearing is an extremely common problem, and by treating it with eyelid hygiene and occasional artificial tear drops, good improvement can often be obtained.

But should surgery be performed? Obviously, this depends on the individual

case, but in the average person who has only mild symptoms that are an occasional annoy-

ance, a conservative outlook toward surgery is warranted. Why subject yourself to the risks and uncertainties of surgery if you have a problem you can live with? If I had a very mild tearing problem, I would certainly think twice before undergoing surgery.

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Inflammation and Enlargement of the Tear Gland

Enlargement of the tear gland is generally noticeable and may produce what is called an S-shaped deformity of the upper eyelid. This means that the margin of the eyelid toward the outside of the eye becomes pushed downward, while the eyelid toward the inner corner of the eye maintains its normal position, resulting in a gentle “S” curve to the eyelid margin. There are many reasons why the tear gland may become enlarged. It can be affected by both benign and malignant tumors. It may become enlarged by inflammation in Sjögren’s syndrome as well as other autoimmune diseases (those in which the immune system attacks the body’s own tissues). The term dacryoadenitis is used to refer either to inflammations of this nature or to infections of the tear gland. Swelling, pain, and redness are often present. If a bacterial infection is suspected, then antibiotics are given, generally with good results.

Common Eyelid Tumors

Growths on eyelids are very common. Some kinds of growths occur almost exclusively on the eyelids. Others often occur elsewhere on the body as well. We will review the ones that are seen most often.

Epithelial Inclusion Cyst

A very common finding on the eyelids is the epithelial inclusion cyst. It looks like a tiny white bead in the skin. The “white bead” represents the contents of one of the glands of the skin. These are simple to remove if you choose to do so. A very tiny incision is made in the skin over the white bead, which is then easily “shelled out.” They generally do not recur.

Oil Gland Tumors

A chalazion is a pea-sized lump in the eyelid, often accompanied by inflammation, that results from a blocked oil gland. (See

“Chalazia and Styes,” page 64.) They are benign. However, there is a rare kind of cancer that can begin in an oil gland and can sometimes masquerade as a

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chalazion. Therefore, if what appears to be a chalazion persists and continues to grow, despite both medical and surgical treatment, it may be wise to biopsy it just to make sure it is not malignant.

Xanthelasma

Middle-aged and elderly people may sometimes develop a yellowish, raised growth on the lids, most commonly in the half of the eyelid toward the nose. This is a xanthelasma, a cholesterol deposit in the skin. Some people who develop a xanthelasma do not have high blood cholesterol levels, but others do. Therefore, if you have a xanthelasma, it is a good idea to have your cholesterol level checked if it has not been done in the past few years. Xanthelasmas are only a cosmetic problem and do not cause harm. If removal is desired, they can be cut away with surgery or removed by application of a weak acid to the area. This, of course, should be done only by a physician experienced in the technique.

Papilloma

Papillomas are warty, benign growths that often appear between the eyelashes. The bigger they become, the more difficult they are to remove and the more likely they are to recur. Therefore, papillomas that are growing should be surgically removed by an ophthalmologist. So-called skin tags, which look like microscopic fingers of skin that grow out from the lid away from the eyelashes, are also papillomas but are much easier to treat.

Molluscum Contagiosum

Molluscum contagiosum is a virus infection that produces small, round, white nodules that are often hidden among the eyelashes. It can cause a chronic inflammation on the surface of the eye that goes away once the nodule is removed. Often, even partial removal of the nodules does the trick as the immune system takes over. People with immune system problems such as acquired immunodeficiency syndrome (AIDS) may develop many of these nodules, which can be very resistant to treatment.

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Basal Cell Carcinoma

The most common cancers on the eyelids are basal cell carcinomas. These cancers are related to excessive sunlight exposure, so they are common on all areas of the face. There is some evidence that a low-fat diet can reduce the risk. Fortunately, most people today have heard about the dangers of excessive sun exposure and are using sunscreens, wearing

hats, or just limiting their time in the sun. Of course, ultraviolet-absorbing glasses,

either sunglasses or regular, also provide pro-

tection. Basal cell carcinomas may be round or irregularly shaped lesions, often with a somewhat shiny surface traversed by tiny, thready blood vessels. The center part of the tumor may eventually become ulcerated.

Any lesion with a suspicious appearance should be biopsied. The biopsy is really a very simple procedure. The area is numbed, and a small blade is used to shave off the part of the tumor extending above the level of the surrounding skin. No attempt is made to remove the tumor completely at this point. The tissue removed is then examined by a pathologist. If it is a benign lesion, nothing more need be done. But if it turns out to be a basal cell carcinoma, complete removal is required. Although we don’t normally think of basal cell carcinomas as a cause of death, in rare cases, they can spread to the area behind the eye and even to the brain.

Surgical removal of a basal cell carcinoma near the margin of the eyelid usually involves a pentagonal block resection. This means that an entire segment of the eyelid, roughly in the shape of “home plate,”is removed in the area of the tumor. It is then sent to the pathologist, who confirms the diagnosis on the spot. The pathologist also indicates

whether any of the tumor extends right up to the edge of the segment of removed tissue. If so, additional eyelid tissue may have to be removed. It is well known that, unlike most

cancers, many basal cell carcinomas do not regrow even if they have not been completely removed. However, when we’re dealing with the eyelid, there is less margin for error than elsewhere, and it is generally advisable to try to remove 100 percent of the tumor. Once the tumor removal is complete, the remaining portions of the eyelid can be sewn back together. If a large portion of the lid has been removed, this may necessitate advanced plastic surgical techniques.

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An alternate way of removing a basal cell carcinoma is to use a technique called Mohs’s micrographic surgery. Some dermatologists have been specially trained in this technique. Very thin slices of tissue around a tumor are removed and immediately examined under the microscope for the presence of residual tumor cells. The area is carefully mapped out to ensure complete removal. This technique, which is often used in more difficult cases, aims for 100 percent removal of the cancer with the least possible loss of normal tissue. Plastic surgical techniques may then be used to repair the defect in the eyelid, either at the time of the Mohs’s surgery or later. Mohs’s micrographic surgery has an unparalleled success rate in terms of tumor recurrence.

Squamous Cell Carcinoma

Squamous cell carcinoma is the other common skin cancer and is also related to sunlight exposure. It is less common than basal cell carcinoma but is more aggressive and invasive. The surgical techniques used to treat basal cell carcinoma are used here as well, but it is even more important to assure that a squamous cell carcinoma has been completely removed.

As with basal cell carcinoma, a low-fat diet may help reduce the occurrence of the squamous cell variety. In a recent study, consumption of citrus peel (rind, zest) was found to reduce the risk of squamous cell carcinoma of the skin by 34 percent. Researchers suspect that a substance called limonene in the oil of the peel may be responsible for the anticancer effect. If you eat citrus peel, you should probably get some that was grown without pesticides.

Ectropion and Entropion

Ectropion is a condition in which the margin of the eyelid turns outward. Entropion, in contrast, involves a turning inward of the eyelid margin. Most cases of ectropion and entropion involve the lower lids.

Causes of Ectropion

Ectropion generally occurs in older individuals as aging causes the lower lid to elongate and become lax. When the margin of the lower eyelid is not in contact with the eye, the tears are not able to find their way into the tear drainage

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