Cataract

A cataract is a clouding of the normally clear lens of the eye. The lens, which lies just behind the pupil, helps the eye to focus. When the lens becomes clouded, the passage of light to the back of the eye is partially blocked, and a person’s ability to see is reduced. This clouding of the lens of the eye is called a cataract. Thus, a cataract is not a growth or a tumor, but a change in the clarity of the lens.

Cataracts may form in the eyes of people of any age, but they are most common in older adults. In fact, after age 65, many people have a cataract. It is important to remember that if you have a cataract, you may not necessarily require an operation because many people have some minor clouding of the lens that does not affect vision. An operation to remove the cataract becomes necessary only if the patient’s vision and ability to function become impaired. If you do need an operation to remove a cataract, you should know that advances that have been made in cataract operations in recent years have made cataracts one of the most treatable of eye disorders.

Remember, as common as cataract surgery is, no two people undergoing the procedure are alike. The reasons for and the outcome of any operation depend on your overall health, age, the severity of lens opacity (cloudiness), and any other abnormalities of the eye or existing health conditions.

What Causes Cataracts?

Most people who develop cataracts are older adults. Almost everyone over the age of 65 has a cataract in one or both eyes that interfere with vision. Diseases, such as diabetes, and the long-term use of some medications, such as corticosteroids, can contribute to the formation of cataracts. Physical injuries, such as a puncture wound to the eye, and injuries caused by chemicals hitting the eye or by exposure to excessive X-rays, intense heat or, possibly, too much sunlight also can cause cataracts. In addition, smokers tend to have a higher occurrence of cataracts than non-smokers.

Cataracts may take years to form, or they may worsen rapidly in a few months. Furthermore, cataracts can affect both eyes at the same time, but they may develop at different rates. People with cataracts often experience one or more of the following symptoms:

• Blurred or hazy vision.
• Poor vision at night or in very bright light
• Difficulty driving, especially at night because of glare from headlights of oncoming cars.
• Seeing “ghost” images.
• Change in color vision.
• Loss of contrast.
• Poor distance vision.

Many people do not need to have an operation for a mild cataract. But when a cataract begins to interfere with your ability to carry out desired tasks — for instance, if you have difficulty reading a newspaper or you experience difficulty driving — it is time to discuss the option of a cataract operation with your ophthalmologist

Can Cataracts Be Treated Non-Surgically?

Cataracts do not go away on their own or with the use of medication. The only way to treat cataracts is to have them removed surgically. However, there are a few things that can be done to provide temporary relief from the symptoms of cataracts until an operation can be performed. Eye drops that widen the pupil of the eye may help you to see better if the cataract is small and near the back of the lens; your surgeon will be able to determine the exact location of the cataract and whether eye drops may be a temporary option for you. Wearing sunglasses or other special types of glasses will protect your eyes from sunlight.

Wearing a visor to prevent light from shining directly into the eyes is often helpful. Also, using standard 60 or 100 watt light bulbs or brighter instead of fluorescent lighting may help you to see better indoors.

Screening And Diagnosis

An eye specialist can detect and track the development of cataracts during routine eye exams. Have your eyes examined:

• Every 2 to 4 years if you’re between ages 40 and 65
• Every 1 to 2 years if you’re 65 or older
• Any time you develop new, unexplained eye symptoms

If you find yourself “fighting” with your eyes – blinking more often to clear your vision of what may feel like a thin film over your eyes – or you experience other symptoms of cataracts, see your eye doctor. An eye doctor can diagnose cataracts with the help of a careful eye exam.

If it’s determined that you have cataracts, an assessment of how cataracts affect your day-to-day life can help determine whether the next step should be surgery.

• Surgical Removal of Cataracts
• Cataract Surgery Techniques

Extracapsular cataract extraction technique

The surgeon makes an incision where the cornea and sclera meet. Carefully entering the eye through the incision, the surgeon gently opens the front of the capsule and removes the hard centre, or nucleus, of the lens. Using a microscopic instrument, the surgeon then suctions out the soft lens cortex, leaving the capsule in place.

Phacoemulsification

It is a modification of the extracapsular cataract extraction. In Phacoemulsification, the nucleus is fragmented by an ultrasonic oscillating probe. The nuclear fragments are simultaneously suctioned from the eye. The size of the incision is smaller than the incision needed to remove the capsule in the extracapsular technique.

An intraocular lens (IOL) is a clear plastic lens that is implanted in the eye during the cataract operation. Lens implants have certain advantages. They usually eliminate or minimize the problems with image size, side vision and depth perception noted by people who wear cataract eyeglasses. They are also more convenient than contact lenses because they remain in the eye and do not have to be removed, cleaned, and reinserted.

Recovery

You may experience some swelling of the eye area immediately after the operation. If you do, it can be treated with eye drops that contain anti-inflammatory medication. Fortunately, infection is rare after a cataract operation. Nonetheless, an antibiotic ointment or eye drops may be applied directly to the eye for several weeks to ensure that no infection develops.
You should be up and walking soon after the operation. However, you may find that exposure to bright light is uncomfortable. Sunglasses and eye drops can relieve most discomfort you may experience.

Your level of activity will depend on your surgeon’s instructions. Usually, you can resume normal, non-strenuous activity on the first day after the operation. You also may be asked to wear eyeglasses, both indoors and outdoors, for seven-to-10 days following the operation. In addition, to prevent scratching or irritating the healing wound, you may be asked to sleep with a protective eye shield until the healing process is well underway.

Are There Any Complications?

As with any surgical procedure, there may be complications that occur during or following cataract removal. Although complications are rare, those that occur most commonly are:

• Inflammatory reaction. Your eye and the area around it may swell and be tender or painful. You will be treated with an antibiotic and/or anti-inflammatory drugs in drops, by local injection, or through the bloodstream. Very rarely, if the infection progresses, small amounts of an antibiotic may be injected into the eye.
• Fluid in the retina (or macular edema). This complication occurs more commonly in people who have certain conditions, such as diabetes. Although the problem usually clears up by itself, eye drops or pills are sometimes used to help remove the fluid.
• Other serious, but less common complications, that may occur following cataract surgery include dislocation of the lens implant, infection, retinal detachment and excessive bleeding. You should discuss these unlikely difficulties with your ophthalmologist if you are concerned about them.
  Life After Surgery.

Once a cataract has been removed, light can once again pass undistorted through the cornea and the IOL to the retina (back of the eye). However, your vision will not be clear unless the light is focused directly on the retina; eyeglasses provide that focus, so you may be required to wear glasses to see more clearly.

In addition, the artificial implanted lenses or IOLs cannot change shape the way the eye’s natural lens did when you were younger, and you will most likely need to wear bifocal lenses or reading glasses in order to see clearly at close range. It is important to note that you may need to have your eyeglass prescription changed following a cataract operation.

Glaucoma

Glaucoma isn’t one disease. Instead, it’s a group of diseases that cause damage to the optic nerve. In most cases, this damage is the result of increased pressure within your eye. As the optic nerve deteriorates, the patient gradually loses the ability to see to the side (peripheral vision). With time your central vision may begin to decrease as well. If Glaucoma isn’t treated, it eventually may lead to total blindness.

In fact, Glaucoma is the second most common cause of blindness. That’s because Glaucoma often gives no warning sign until permanent damage has already occurred. In most cases the onset is so gradual you’re not aware you’ve lost some of your peripheral vision. There are several types of Glaucoma, including primary open-angle glaucoma, angle-closure glaucoma, congenital glaucoma and secondary glaucoma. Primary open-angle glaucoma develops slowly and painlessly when normal eye fluid known as aqueous humor doesn’t drain properly, causing pressure to build up within your eye. It accounts for 60 percent to 70 percent of all Glaucoma cases.

About 10 percent of people with Glaucoma have angle-closure glaucoma, which occurs suddenly and often causes dramatic symptoms. This type of Glaucoma is a medical emergency and requires immediate treatment. A much smaller number of people have congenital glaucoma, which is present at birth, or secondary glaucoma, which results from trauma, chronic steroid use or disease.

Still, the news about Glaucoma is encouraging. When it’s detected and treated early, Glaucoma need not cause blindness or even severe vision loss for most people.

Signs and Symptoms
The signs and symptoms of Glaucoma vary, depending on the type of Glaucoma.

Primary open-angle glaucoma

Primary open-angle glaucoma often goes undetected for years. The pressure within the eye increases gradually, with no early warning signs. But eventually, you lose more and more of your side vision until only a narrow section of your visual field remains clear. This type of Glaucoma tends to affect both eyes, although you may have symptoms in just one eye first. In addition to reduced peripheral vision, the signs and symptoms of primary open-angle glaucoma may include:

• Sensitivity to glare.
• Trouble differentiating between varying shades of light and dark.

Angle-closure glaucoma

Attacks of angle-closure glaucoma often develop suddenly, but you also may have preliminary warnings weeks or even months ahead of a severe attack. Glaucoma attacks usually occur in the evening when the light is dim and your pupils are dilated. The pain may be very severe and cause vomiting. Other signs and symptoms of acute glaucoma may include:

• Blurred vision, usually in just the eye involved.
• Halos appearing around lights.
• Reddening of your affected eye.

Congenital glaucoma

This type of Glaucoma is usually present at birth, but signs and symptoms — such as eyes that seem cloudy, are often watery or teary or are sensitive to light — may not appear until an infant is a few months old.

Secondary glaucoma
The symptoms of secondary glaucoma will vary, depending on the cause.

Causes

Your eyes are part of an elegant and complex process that transforms waves of light into images you see. The process begins when light enters your eyes through a clear tissue known as the cornea. Behind the cornea, the colored portion of your eye — the iris — regulates the amount of light that passes through to the lens.

The lens then focuses this light onto the retina, a thin, transparent membrane in the back portion of your eye. The retina translates light into signals that are sent to your optic nerve, and the optic nerve sends these signals to your brain, where they’re interpreted as images. This is what allows you to see.
The internal structures of your eye are nourished by a clear fluid called the aqueous humor.

This fluid circulates from behind your iris through the dark opening in the centre of your eye (pupil) and into the space between your iris and your cornea. The aqueous humor not only nourishes your eyes but also exerts a constant pressure (intraocular pressure, or IOP) that helps maintain your eyes’ shape.

Healthy eyes constantly produce aqueous humor. To keep from building up in the eye, the fluid drains primarily through what is called the trabecular meshwork. This drainage occurs in a “drainage angle” located at the point where your iris and cornea meet. From here, the excess fluid flows into a channel (Schlemm’s canal), and then into a system of small veins on the outside of your eye.

Sometimes, though, the drainage angle doesn’t function properly. This causes the aqueous humor to back up and put pressure on another fluid, the vitreous humor, which is located behind the lens. The increased pressure within the vitreous humor presses on the fibres of the optic nerve, slowly damaging them. The result is a gradual loss of vision.

Primary open-angle glaucoma

In this type of Glaucoma, the drainage angle in your eye remains open, yet the aqueous fluid doesn’t drain properly. It’s not entirely clear why this happens, but you’re much more likely to develop primary open-angle glaucoma as you get older. It may be that your cells don’t drain aqueous humor as efficiently later in life.

Angle-closure glaucoma

Unlike primary open-angle glaucoma, which damages your vision over a period of months or years, acute angle-closure Glaucoma develops suddenly. In most cases, people with this type of glaucoma have a very narrow-angle where the aqueous fluid drains between the iris and cornea. When their pupils become unusually dilated, the angle may close completely, causing a sudden increase in pressure and triggering an acute attack.

In some people, the narrow drainage angle may simply be a structural problem. In others, it may be the result of ageing. Generally, as you age the lens in each eye gradually becomes larger, pushing your iris forward and narrowing the angle between your iris and cornea. In both cases, factors that cause your pupils to dilate may close the angle completely. These include:

• Medications. Certain drugs, such as antihistamines and tricyclic antidepressants, dilate your pupils. Also, do some drops your ophthalmologist may use to dilate your eyes during an eye exam.
• Darkness or dim light.
• Emotional stress.

Secondary glaucoma

This type of Glaucoma occurs in people who have other eye conditions and may be caused by any of the following:

• Medical conditions. People with diabetes are at especially high risk for secondary glaucoma.
• Medications. Certain medications, especially corticosteroids, increase the pressure in your eye. This includes steroids you inhale or take orally as well as steroid ointments you apply to your eye.
  Physical injury. Severe trauma to the eye can increase intraocular pressure, leading to secondary glaucoma.

Risk Factors

The majority of people with slightly increased intraocular pressure don’t develop Glaucoma. This can make it difficult to predict just who will develop the disease. But certain factors may increase your risk. They include:

• Age. Your chance of developing Glaucoma begins to increase after age 40. In fact, primary open-angle glaucoma is most common in older adult women. But although the incidence of Glaucoma increases as you grow older, the disease is not considered a normal part of ageing.
• Race. Black Americans are three to four times more likely than white Americans to get Glaucoma and six times more likely to suffer permanent blindness as a result of the disease.
  
  The exact reasons for this aren’t known, although black Americans may be more susceptible to a damage of the optic nerve and may respond less well to current therapies than white Americans. Asians, particularly those of Vietnamese descent, are also more susceptible to glaucoma than whites. And people of Japanese ancestry are more prone to develop a type of Glaucoma in which intraocular pressure is normal (low-pressure glaucoma).
• Family history. If you have an immediate relative — such as a parent or sibling, with Glaucoma, you have a 20 percent chance of also developing the disease.
• Diabetes and other medical conditions. If you have diabetes, your risk of developing Glaucoma is three times greater than that for people who don’t have diabetes. It’s possible that having extreme Myopia (nearsightedness) or a history of high blood pressure (hypertension) or heart disease may also increase your risk.
• Injuries. Past injuries to your eyes or eye surgery may trigger secondary glaucoma, so may any type of inflammation, especially uveitis, an inflammation of the eye that is sometimes associated with inflammatory bowel disease and juvenile rheumatoid arthritis.
• Corticosteroid use. Your risk of developing secondary glaucoma increases if you take oral corticosteroids for prolonged periods of time, if you use inhaled steroids for asthma or you apply a steroid cream or ointment to your eyes.

When To Seek Medical Advice

Primary open-angle glaucoma gives few warning signs until permanent damage has already occurred. That’s why regular eye exams are the key to detecting glaucoma early enough for successful treatment. It’s best to have routine eye checkups every 2 to 4 years after age 40 and every 1 to 2 years after age 65.

Don’t wait for symptoms of any kind to occur. If you have one or more risk factors of glaucoma, talk to your doctor about scheduling regular eye exams. Your doctor can perform some tests, but others need to be done by an eye care specialist.

In addition, be alert for signs of an acute angle-closure glaucoma attack, such as a severe headache or pain in your eye or eyebrow, nausea, blurred vision or rainbow halos around lights. If you experience any of these symptoms, seek immediate care at your local hospital emergency room.

If you’ve been diagnosed with Glaucoma, establish a regular schedule of examinations with your doctor to be sure your treatment is helping maintain a safe pressure of the fluid in your eyes.

Screening And Diagnosis

A simple, painless testing procedure known as tonometry can alert you and your physician to the possibility you may have Glaucoma. Tonometry measures the pressure within your eyeball. Normal intraocular pressure ranges from 10 to 21 millimetres of mercury. If your pressure is higher, your ophthalmologist can perform further tests to help determine whether you have Glaucoma.

Air-puff tonometry

Air-puff tonometry uses air to measure eye pressure. It does this by measuring the amount of force needed to indent your eye. This test is useful for preliminary Glaucoma screenings.

Applanation tonometry

An applanation tonometer is a sophisticated device that’s usually fitted to a slit lamp, a common instrument for the eye examination. For this test, your eyes will be anesthetized with drops and the tonometer placed directly on your eye. The pressure readings from this test are extremely accurate.
Keep in mind that a high-pressure reading doesn’t necessarily mean you have Glaucoma. At the same time, it’s possible to have damage to your optic nerve and still have normal intraocular pressure. For these reasons, your ophthalmologist may choose to perform tests to check your optic nerve or your peripheral vision.

Tests for optic nerve damage

Your ophthalmologist may use an instrument called an ophthalmoscope to examine the back of your eye (fundus) and check the health of the fibres in your optic nerve. Damaged fibres may be asymmetrical or pale in color. Your doctor may also use a combination of laser light and computers to create a three-dimensional image of your optic nerve. This can reveal very slight changes that may indicate the beginnings of Glaucoma.

Visual field tests

Glaucoma gradually diminishes your ability to see to the side. That’s why your ophthalmologist may recommend perimetry tests to check your peripheral vision. Some of these tests, which involve watching a monitor with hundreds of flickering lights, can be quite complex. Yet perimetry tests are still the best method for measuring peripheral vision. If you have optic nerve damage, you may need visual field testing as often as every 1 to 4 months for a time.

Other tests

To distinguish between primary open-angle and angle-closure glaucoma, your ophthalmologist may use an instrument known as a gonioscope to inspect the drainage angle between your cornea and iris.

Treatment

You may not need any treatment if your eye pressure is only slightly elevated and there’s no damage to your optic nerve. Instead, your doctor may choose to monitor your condition with regular eye exams. But if you have signs of optic nerve damage, treatment can help slow its progression. Unfortunately, it’s not currently possible to reverse the damage that has already occurred. Most people have good results with Glaucoma medication, but some may need surgery instead.

Medications for Glaucoma

Most Glaucoma medications are applied directly to your eyes in the form of drops, although a few may be taken orally. Because a portion of the drops may be absorbed into your bloodstream, you sometimes may have side effects unrelated to your eyes. In addition, some medications may lose their effectiveness over time. In that case, you may need to change or add medications or have surgery to control your Glaucoma.

It’s not always easy to use Glaucoma medication as directed. Drops usually need to be applied several times each day, and if you’re using more than one medication, you need to wait at least 5 to 10 minutes between applications. This rigorous schedule can sometimes seem time-consuming and confusing.
Furthermore, because Glaucoma rarely causes symptoms in its early stages, you may not notice any change in your vision when you start using medication. Still, it’s extremely important to follow your treatment plan exactly as your doctor prescribes. Skipping even a few doses of medication can cause your Glaucoma to become worse. If you have trouble with your treatment plan, tell your doctor.

Surgery for Glaucoma

When medications aren’t effective or well tolerated, surgery may be an option. Keep in mind that surgery doesn’t cure Glaucoma. As a result, you may need to keep using antiglaucoma medications even after surgery. In some cases, you may need a second operation.

Laser surgery (trabeculoplasty). In this procedure, your doctor uses a beam of high energy light to shrink part of the meshwork of your eye’s drainage angle. This causes other areas of the meshwork to stretch, which helps aqueous fluid drain more easily.

Laser surgery, which usually takes between 10 and 20 minutes, will likely be performed in your doctor’s office under local anesthesia. Following surgery, you should have almost no discomfort, but you’ll need to continue taking eye drops, at least for a time, and you may need more surgery within 5 years. In some cases, intraocular pressure actually may increase following laser surgery. In most cases this is temporary, but sometimes the rise in pressure may be permanent, leading to further vision loss.

Trabeculectomy. In this procedure, a surgeon creates a new drainage pathway for fluid in the white part of your eye (sclera) using traditional surgical techniques. Many people who have had this type of surgery no longer need eye drops. But there are also risks. In some cases, scars may form that close the drainage channels. This is a particular problem in young people, blacks and people who have had cataract surgery.

Drainage implants. This may be an option for adults when other treatments have failed as well as for infants and children. In this procedure a small silicon tube is inserted in your eye to help drain aqueous fluid. Possible complications include the clouding of the lens of your eye (cataracts) and implant failure.

Medications and surgery for acute glaucoma

Doctors may administer several different medications during an attack of acute glaucoma in an effort to reduce eye pressure as quickly as possible. Once your eye pressure is brought under control, you may have an emergency operation known as an iridotomy to create a drainage hole in your iris. This surgery is now almost exclusively performed with lasers, which allow specialists to form an opening without making an incision in your eye. Laser iridotomy is an outpatient procedure that avoids many of the risks of traditional surgery. After treatment, you can usually resume your normal activities right away.

Treatment for low-tension glaucoma

Although eye pressure in this type of Glaucoma is normal, treatment with standard antiglaucoma medications seems to slow the progress of the disease.

Prevention

There is no known way to prevent Glaucoma, but regular checkups can help detect the disease in its early stages before irreversible damage has occurred. As a general rule, have eye exams every 2 to 4 years if you’re between the ages of 40 and 65. It’s best to have your eyes examined every 1 to 2 years if:

• You’re 65 years or older.
• You have a family history of eye disease.
• You’re of African or Asian ancestry.
• You have diabetes or a chronic inflammatory disease, such as rheumatoid arthritis.
• You’re taking corticosteroids.
• You may need even more frequent check-ups if you’ve been diagnosed with abnormally high intraocular pressure or have a history of serious eye injury.