Cataracts: A Complete Guide to the Symptoms, Causes and Treatment

What is a Cataract?

A cataract is a clouding of the eye’s lens that causes a progressive, painless loss of vision. Although this eye disease is the leading cause of blindness worldwide, the exact cause of cataracts is still unknown. Many experts believe there are a number of contributing factors, such as age, illness, injury, or certain medications.

According to the National Eye Institute, “By age 80 more than half of all Americans either have a cataract or have had cataract surgery.”

Cataracts typically develop in one eye, but people who have had a cataract in one eye are more likely to develop one in the other eye at some point. Sometimes cataracts develop in both eyes at the same time.

In a normal eye, light enters the eye and passes through the lens. Colors are vibrant, images are clear, and the eyes are able to adjust to changes in lighting.

When a cataract is present, however, images are distorted or blocked altogether, and colors seem dull and more yellow. Most people notice that their vision becomes blurry when they begin to develop cataracts.

What Are the Different Types of Cataracts?

  • Age-related cataracts: Protein builds up in the lens and causes cloudiness or discoloration of the lens.
  • Secondary cataract: Forms after surgery for other eye disease like glaucoma or diabetic retinopathy
  • Traumatic cataract: Forms after eye injury
  • Congenital cataract: Present at birth due to birth defects, diseases, or other problems
  • Radiation cataract: Forms after severe radiation exposure
  • Nuclear cataract: Forms in the center of the lens
  • Posterior Subcapsular cataract: Forms in the back of the lens


Cataract Symptoms

Symptoms of cataracts can differ for each person, depending on the type of cataract they have. Symptoms for all types of cataracts may include blurry vision or glare from car headlights, especially at night. Sunlight or indoor overhead lighting may seem to be too bright or cause glare. You may notice that bright colors appear dull. You may also notice everything seems to be slightly yellow.

Sometimes cataracts can cause double vision, and you may find that you are frequently changing contact lens or eyeglasses prescriptions. The degree of vision change depends on the intensity of the light entering the eye and the location of the cataract.

As an example, let’s discuss a centrally located cataract for a minute:

Normally the pupil constricts in bright light, narrowing the pathway through which light enters the eye. When a cataract is present, the light has a difficult time passing through the cataract, especially when it is centrally located (this is called a nuclear cataract).

When it is dark, the pupil dilates, which causes bright lights that suddenly appear in the darkness (such as headlights approaching on a dark road) to scatter at the edge of the cataract, causing glares and halos.

When a cataract develops in the back of the lens (a posterior subcapsular cataract) it affects a person’s vision more than a cataract in another location because the cloudiness is at a point where the light rays are already focused in a narrow beam. The effect of going from brightly lit rooms into dark ones can be more extreme and cause an even greater loss of vision. The severity of the symptoms can depend on the location of the cataract.

Occasionally you may experience cataract-like symptoms, but those symptoms may be a sign of another eye-related problem. This is why it is advisable to see your eye doctor if you are experiencing any changes in your vision.

Diagnosing Cataracts

The eye doctor will put drops in your eyes to dilate your pupils and then perform a thorough eye exam. He or she will study the crystalline lens of your eye and check the optic nerves and retina for changes that may be contributing to your vision problems. This is typically done with an ophthalmoscope, which is a handheld tool used to look inside the eye.

Using an instrument called a slit lamp, your eye doctor can identify the location of the cataract and determine its severity. The eye doctor may also perform a tonometry test in order to measure the pressure inside your eye. This is one of the diagnostic tools for glaucoma.


What Causes Cataracts?

The lens of an eye is made up of water and protein. The protein is arranged in a way that keeps the lens clear and allows light to pass through. A cataract forms when some of the protein clumps together and begins to cloud a portion of the lens. Over time it grows larger and affects your vision.

Although the exact cause of cataracts remains a mystery, many experts believe it has to do with the aging process. In the United States, 20 percent of people between the ages of 65 and 74 develop cataracts severe enough to reduce their vision, and almost half of all people over 75 have cataracts.

Cataracts seem to be more common when age is coupled with:

  • Malnutrition or poor eating habits
  • Exposure to certain drugs, such as corticosteroids, for long periods
  • Exposure to ultraviolet light over long periods
  • Exposure to x-rays for long periods
  • Darker eyes
  • Alcohol use
  • Intrauterine infection during the first trimester of pregnancy
  • Surgery for other eye problems
  • Injury to the eye (cataracts can develop many years after an injury)
  • Family history of cataracts

There are also several diseases that can cause cataracts or increase the risk of developing them. These include:

  • Down’s syndrome
  • Werner’s syndrome
  • Atopic dermatitis
  • Myotonic dystrophy
  • Occult tumors (e.g., choroidal melanoma in adults and retinoblastoma in children)

Cataract Surgery

The only effective treatment for cataracts is to have them surgically removed. Cataract surgery is one of the most frequently performed surgical procedures in the United States, and it has a greater than 95 percent success rate when performed by an experienced cataract and lens implantation surgeon. Many people compare the physical impact of cataract surgery to having a tooth extracted.

Surgery is almost always performed under local anesthesia, and only the eye’s surface is numbed, either by injection or eye drops. If the patient cannot hold still for the surgery—as young children often cannot—general anesthesia may be used, but these situations are rare.

Cataract surgery usually requires the replacement of the natural lens with an intraocular lens (IOL). The cloudy natural lens is replaced with a clear IOL, thereby giving you better vision.

Today’s ophthalmologists can actually replace the cloudy lens with a technologically advanced intraocular lens such as Crystalens® or ReSTOR®, which will correct not only your distance vision but your near- and arm’s-length vision as well. These are more similar to the natural lenses you had when you were younger, and can restore the up-close vision you lost in your forties, when you became presbyopic.

There are two types of cataract surgery used today. They are called phacoemulsification and extracapsular surgery. In phacoemulsification, or “phaco” for short, a tiny incision is made in the cornea, and a computer-assisted device emits ultrasound waves to break the lens into tiny pieces. The pieces are then removed and replaced with an IOL.

In extracapsular surgery, a longer incision is made, and the cloudy core of the lens is removed as a whole piece while any leftover parts of the lens are sucked up.

In the vast majority of cases, cataract surgery and lens implantation is performed in an outpatient setting, meaning that you will be able to go home within a few hours of having your cataract removed and a new lens implanted. You can generally expect to be able to resume your normal work and recreational activities within a few days.

After Cataract Surgery

Your doctor will make an appointment to see you the day after cataract surgery and a few more times after that to check up on your healing process. During this time you should be careful not to put any pressure on the eye by rubbing your eyes or bending over.

Because of the surgery and eye drops, you may have fluid discharge. Some people may experience pain, discomfort, or itchy eyes. Your doctor may give you medication to help relive these symptoms.

Typically you are given eyeglasses or a metal shield to wear to protect the eye from injury until healing is complete, usually within a few weeks. For people who have cataracts in both eyes, most doctors wait two to four weeks for the first eye to heal before performing surgery on the other eye

Most people notice an improvement in their distance vision within a few days or weeks after surgery. Unless an advanced-tech IOL, (i.e., a multifocal) is implanted, most people who undergo cataract surgery will need eyeglasses for reading, and some will still need eyeglasses to obtain the best possible distance vision as well.

Unless you were put under general anesthesia, you should be awake, alert, and fully capable of understanding instructions after the procedure. If you were put under general anesthesia, it is important that the person driving you home understands the doctor’s instructions. Although instructions may vary, here are some basic guidelines to help you heal properly:

The Day of the Surgery

On the day of the surgery, you will need a ride home from the surgical center. You and your driver may also need to stop at a pharmacy to fill a prescription. You will probably feel discomfort and experience blurred vision.

Some people find that their eyes are itchy or that they have a sensation of a foreign body in the eye. Some patients also experience photophobia (sensitivity to light).

You may be instructed to close your eyes and rest them as the numbing drops wear off. This sensitivity will usually last until the end of the day following the procedure.

The Day After Cataract Surgery

There is a very good chance your vision will still be blurry, so on the day after surgery you will need to find a ride back to your doctor for a follow-up appointment.

Your doctor will also want to know the severity of your symptoms. Even if your symptoms are severe, your doctor may be able to alleviate them. For example, if you are in pain, you may be given a pain reliever.

Generally you will be given eye drops to help with the inflammation and reduce the risk of infection. These drops should come with instructions explaining when to use them and how much to use.

The Week After Surgery

Your vision will probably remain blurry for the first few days following cataract surgery, but the eye drops should help with the symptoms. Your doctor will schedule a follow-up appointment during this first week (you will need to find a ride to this appointment).

The purpose of the follow-up appointment is to monitor your progress and to see how well you are healing. You will also be limited in your normal activities. For example, you will not be allowed to bend over or lift heavy objects. You will also be asked to stay away from situations that may cause debris to enter your eye, which could increase the risk of infection.

Two to Eight Weeks After Surgery

If you are healing well, your follow-up appointments will be less frequent than before. Typically you’ll be given eyeglasses or a metal shield to wear to protect the eye from injury until healing is complete.

For the first couple of weeks following surgery, you will need to protect your eyes. This includes keeping water out of them. You will need to keep your eyes closed while bathing, and swimming, and other types of water activities should be avoided. Call your eye doctor if you have any questions or concerns.

Talking to Your Doctor

Here are some questions to ask your doctor about the days and weeks following cataract surgery:

  • When is my next appointment?
  • How many prescriptions do I need to pick up right now?
  • Where should I pick up my prescription?
  • Which symptoms should I expect today and tomorrow?
  • What should I expect at my next appointment?
  • When can I eat a real meal again?
  • When can I have something to drink?
  • What limitations will I have, and how long will I have them?

Most people will need to continue wearing eyeglasses after surgery, at least for reading. Cataract surgeons pride themselves in calculating implant lens powers so that patients won’t have to wear glasses for distance vision. Multi-focal implant lenses are also available at an additional cost that correct distance and near vision.

Cost of Cataract Surgery

The average cost of cataract surgery is about $3,000.00, but this price may vary depending on the surgeon, the facility, and the family’s insurance. In some cases, cataract surgery for children may be more expensive. Talk with your eye doctor about the actual cost of surgery.

Cataract Surgery Complications

  • Thankfully, complications after cataract surgery are rare, but they do occur in some people. Statistically serious complications occur in about 5 percent of healthy patients.
  • During the first week or so following surgery, many people experience blurry vision, itchy eyes, and discomfort. These types of complications are common and almost inevitable in any case.
  • To prevent further complications, you should follow all your doctor’s instructions—take all medication as directed, show up to all follow-up appointments, limit activities such as swimming, and as noted above, avoid bending over, lifting heavy objects, and rubbing or touching your eyes.
  • More serious complications of cataract surgery may include infection, bleeding, pain, swelling, and sometimes something called an “after-cataract.” This is a condition in which tissue surrounding the IOL becomes cloudy. Fortunately, an eye surgeon can easily eliminate the after-cataract by using a laser, without any additional surgery. This procedure, called a YAG laser capsulotomy, is extremely effective and relatively quick and simple.

The most common complication following cataract surgery is the development of haziness in the tissue behind the eye where the original lens was removed. This is called a secondary cataract. A secondary cataract is not technically a cataract, but a film that forms on the implanted plastic lens.

Approximately one in four people who undergo cataract surgery experience this problem. It can develop months or even years later, but it tends to occur after an artificial lens is implanted. Typically, treatment involves using a laser to make a small opening to let light through.

Additional cataract surgery complications may include:

  • Pressure in eye (if left untreated, glaucoma could develop)
  • Macular edema (swelling)
  • Bleeding in eye
  • Persistent corneal edema
  • Infection
  • Implant becomes dislocated
  • Loss of vision

On rare occasions, more specifically in those with retinal disorders such as diabetic retinopathy, vision worsens after the surgery. Proper care after surgery can prevent major complications from developing.

More serious complications that may develop include the development of other conditions and eye diseases such as:

Glaucoma: As mentioned before, sometimes pressure may occur in the eye. If left untreated, this pressure could develop into glaucoma. Your eye doctor will measure the pressure in your eye during your follow-up visits. Early intervention is encouraged to reduce the likelihood of developing glaucoma and experiencing a loss of vision.

Diabetics are also at higher risk for developing a form of glaucoma called neovascular glaucoma. This is a secondary form of glaucoma that can be much more aggressive and damaging, and treatment must be sought in a timely manner to prevent blindness. Talk with your doctor about other forms of glaucoma that you may be at risk for.

Fuchs’ dystrophy: This condition, which begins with blurred vision and photophobia and eventually progresses to corneal blisters and possible blindness, can sometimes be made worse by cataract surgery.

People with Fuchs’ dystrophy sometimes develop cataracts as their condition progresses, and performing cataract surgery can potentially damage the fragile endothelial cells, which are already compromised by the disease. In some patients there is a risk that a cataract may develop following corneal surgery.

Retinal Detachment: Retinal detachment is when the retina peels away from the back of the eye. This can sometimes occur as a result of cataract surgery.

Posterior Vitreous Detachment (PVD): PVD is a condition in which the vitreous humor separates from the retina. Although PVD is not known to affect vision, there is an increased interest in the relationship between the vitreous body and the retina.

Seventy-five percent of people over the age of 65 have already developed or will soon develop PVD. This separation is a normal part of the aging process. Experts believe this condition affects women more than men, and more cases are developing in people in their forties and fifties.

Posterior Capsular Opacification: Also known as an after-cataract, a posterior capsular opacification is a clouding of the posterior lens capsule that can affect visual acuity. In most cases this complication is easily fixed with the use of a laser that removes the central part of the lens capsule in a procedure known as posterior capsulotomy.

Ptosis: More commonly known as a droopy eyelid, ptosis is a condition in which the upper lid hangs over the eye. In some cases it can be severe enough to block one’s vision.

Astigmatism causes blurry vision at all distances. Myopia and hyperopia are also known to accompany astigmatism. Approximately 80 percent of Americans have some degree of astigmatism, but not all cases require treatment. In some cases, the astigmatism may not be noticeable.

Cataract in Children: What Every Parent Should Know

In rare cases, children are born with visible cataracts or develop them during childhood. If you are the parent of such a child, it’s important to understand as much as possible about this condition, and about cataract surgery as an option.

Although cataracts are common among older people, they are also seen in children and infants. According to the Boston Children’s Hospital, approximately one child in 5,000 develops cataracts, and children account for approximately 0.4 percent of all cases.

Children are either born with cataracts (congenital cataracts) or they develop them later. Like adults, children may develop a cataract in one or both eyes, and the cataract can impair vision, depending on its size and density.

It is hard to determine whether a child’s cataract will worsen as they get older, even with treatment. Children who undergo cataract surgery face the same risks and possible post-surgical complications that adults do. However, according to the Centers for Disease Control and Prevention (CDC), the procedure is considered one of the safest procedures in the United States, regardless of the age of the patient.

Types of Congenital Cataracts

There are four types of congenital cataracts your child may develop. The first and most common type of cataract is known as a nuclear cataract. Nuclear cataracts are found in the central part of the lens.

Cataracts found in the front part of the lens are known as anterior polar cataracts. This type of congenital cataract is thought to be inherited, and is usually too small to require treatment.

Cataracts that develop in the back of the lens are known as posterior polar cataracts.

The fourth type of congenital cataract is known as a cerulean cataract. These appear as bluish dots, and are usually found in both eyes. In most cases, cerulean cataracts do not cause vision problems.

Signs Your Child Has Cataracts

Not all cataracts are visible right away in children and infants, since most cataracts at this point are deep within the lens. The best way for parents to check for cataracts, especially if the child is too young to communicate symptoms, is to shine a flashlight into the eye. If the pupil is white or gray, a cataract is present and an eye doctor should be contacted.

Another thing to keep in mind is that a normal child begins to track objects with their eyes at about three to four months old. If your baby is not tracking objects correctly, it could be a sign something is wrong. Jittery eyes may be another sign that a vision problem has developed.

If your child is old enough to communicate, he or she may complain of symptoms like:

  • Blurry vision
  • Cloudy vision
  • Trouble telling colors apart
  • Sensitivity to light
  • Halos around objects
  • A decrease in vision over time
  • Double vision

If your child is complaining of symptoms such as these, make an appointment with an eye doctor. It’s also a good idea to write down the symptoms your child is experiencing, and any abnormalities you’ve noticed.

Causes of Cataracts in Children

In older people there are various reasons why cataracts develop, but in children they are often caused by genetics or by trauma, which accounts for 40 percent of such cases.

Cataracts can also be caused by an infection during pregnancy, such as chickenpox, measles, or rubella. If a pregnant mother develops a disease such as rubella, the risk of the baby developing congenital cataracts increases because the virus destroys the developing cells in the eyes of the fetus.

Some infants lack an enzyme to break down galactose, which is a sugar derived from milk. This missing enzyme allows galactose to build up in the lens and cause cataracts, in much the same way that diabetics develop cataracts. Additional causes of congenital cataracts include:

  • Infection
  • Diabetes
  • Metabolic problems
  • Drug reaction (e.g., tetracycline antibiotics used to treat infections during pregnancy)

In older children, trauma is usually the cause of cataracts. However, 33 percent of children who are diagnosed at a later age were misdiagnosed when they were much younger.

Diagnosing Cataracts in Children

If you’ve had a baby before, you probably know about the National Screening exam. This exam is performed on every newborn within 48 hours of their birth. If cataracts or other eye problems are suspected, the baby is referred to an ophthalmologist for an extensive examination of the eyes and lenses.

During the exam, the ophthalmologist will use an instrument called an ophthalmoscope to look into the child’s eye. If your child is unable to hold still during the exam, he or she may be given an anesthetic. The ophthalmologist will determine whether the cataract is affecting the child’s vision. If it is, surgery may be considered.

Complications of Congenital Cataracts

In some cases, children with congenital cataracts never develop any problems with their vision. However, in many cases the cataract enlarges as time passes. If that occurs, surgery will need to be performed.

If congenital cataracts are present and overlooked, or if treatment is postponed, vision problems such as lazy eye (amblyopia), strabismus, and nystagmus can develop. Some children will find it difficult to focus on objects, and may begin experiencing difficulties in the classroom.

Treatment for Congenital Cataracts

Treatment for your child’s cataracts will depend on the severity of the cataract. If the cataract is not affecting your child’s vision, your doctor may request check-ups more often to monitor the growth of the cataract and the vision changes your child may be experiencing. If the cataract is severe or is affecting your child’s vision, surgery may be performed.

Cataract Surgery for Children

Cataract surgery is performed on children in virtually the same way it’s performed on adults. Although instructions may vary from patient to patient, most patients are asked not to eat or drink anything on the morning of the surgery.

The eye being treated is numbed with either eye drops or an injection. General or local anesthesia will be used, depending on the child’s ability to hold still during the procedure.

The doctor will then make a small incision in the cornea to get to the lens. The lens is then removed and replaced with an intraocular lens (IOL). An ultrasound is not needed to break up the lens, as is done with adults, because a child’s lens is still soft. Adults with cataracts tend to have hard lenses, which happens with aging.

Once the procedure is completed, your child will remain at the doctor’s office so they can be monitored. Typically, cataract surgery is performed on an outpatient basis, so most parents will be able to take their child home that day.

Like an adult patient, the child will need to limit his or her activities for a few weeks. The doctor will want to see your child frequently during that time to monitor the healing process. If your child has cataracts in both eyes, the second eye will be operated on within four weeks after the first eye is treated.

Some children will be given eye patches or shields to help prevent itching, injury, and photophobia (sensitivity to light). Your eye doctor will recommend a wear schedule for your child. For example, some children may only need to wear an eye shield at night while sleeping, while others may need to wear an eye patch throughout the day and night. Most children will need to wear eyeglasses or contact lenses after the surgery.

Complications of Cataract Surgery for Children

Complications after cataract surgery are rare, but they can occur. In children, there is a heightened risk of glaucoma due to pressure build-up. Some children may also experience complications such as poor vision, wandering eye, a dislocated lens, or infection.

To minimize complications, parents are directed to pay close attention to their children to ensure that they do not do things such as bending over and picking up heavy objects. This can be difficult, since most children are full of energy and do not always remember the rules they must follow for the first few weeks following the procedure.

Talking to Your Eye Doctor

Here are some questions to ask your eye doctor about cataract surgery for your child:

  • Based on the severity of my child’s condition, how soon should we consider surgery?
  • Is surgery the only option for my child?
  • If surgery is not performed, what problems will develop later in life?
  • What caused my child’s cataracts?
  • How long will it take for my child to recover?
  • How long will it be before my child can return to his or her normal activities?
  • What kind of medications will my child be on while he or she recovers?

Preventing Cataracts

Although cataracts develop in most people as they age, there are several things you can do while you are young to try to prevent them. If you look back at the list of causes of cataracts, you will find that many of the items listed can be avoided.

For example, exposure to too much sunlight can increase your chances of developing cataracts later in life, but if you wear sunglasses that have a protective coating against ultraviolet rays, you can protect your eyes from the harmful effects of sunlight exposure.

Additional steps you can take to prevent or reduce the risk of cataracts include:

  • If you have another disease such as diabetes, talk with your doctor to ensure that your blood sugar levels are well controlled.
  • Make sure to get enough vitamin C, vitamin A, and carotenoids, which are found in leafy green vegetables such as kale and spinach.
  • If you are a woman, talk with your doctor about taking estrogen after menopause.
  • Talk with your doctor about changing any medications you have been taking for a long time, especially corticosteroids.
  • Get regular or annual eye examinations, especially after the age of 40.

Facts About Cataracts

Cataracts are the leading cause of blindness in the world. Here are some interesting statistics and facts about this common eye disease:

  • 400 out of 100,000 newborns are affected by congenital cataracts.
  • 5,000 out of 100,000 people aged 52–62 are affected by cataracts.
  • 92,000 out of 100,000 people aged 75–85 are affected by cataracts.
  • 46,000 out of 100,000 people aged 75–85 have significant vision loss (20/30 or worse)
  • A third of congenital cataracts are inherited.
  • 10 percent to 38 percent of childhood blindness is attributable to cataracts.
  • People who live at higher altitudes and in climates with high levels of ultraviolet radiation (such as in Tibet) are at an increased risk of developing cataracts.
  • Surgery is more than 95 percent successful in restoring the vision of people who have age-related cataracts and no other eye disease.
  • Blindness occurs in approximately 1 percent of people with cataracts, even after treatment has been rendered.

Talking to Your Eye Doctor

Here are some questions to ask your eye doctor about cataracts:

  • If I notice subtle changes in my vision, how long should I wait to contact you?
  • What has caused my cataract to develop?
  • What can I do to prevent a cataract from developing in my other eye?
  • What foods should my family eat to prevent cataracts?
  • Who will perform my cataract surgery?
  • If you refer me to a surgeon, how closely will you work with him or her before, during, and after surgery?
  • What treatments should I expect if I begin to feel pressure building up?


Sources and References:
We have strict guidelines for each of our sources and references. We rely upon vision, eye and medical information from peer-reviewed studies, medical associations and academic research institions.
  • MDConsult Cataract
  • M. Beers, MD “The Merck Manual of Medical Information” 2nd home edition (Pocket Books, 2003) 1303-1305
  • S. Moore, MD, K. Yoder, MD “Complete Guide to Symptoms, Illness, & Surgery) Revised 5th edition (The Berkeley Publishing Group, 2006) 125: 208
  • M. Lipner Femto technology changing the cataract landscape
  • National Eye Institute, Facts about Cataracts,
  • Boston Children’s Hospital, Cataracts,
  • Boston Children’s Hospital, Cataracts,
  • The Royal National Institute of Blind People, Congenital Cataracts,