What is a cataract?
cataract is a painless, cloudy area in the lens of the eye that blocks the
passage of light to the retina. The retina is the nerve layer at the back of
the eye. The nerve cells in the retina detect light entering the eye and send
nerve signals to the brain about what the eye sees. Because cataracts block
this light, they can cause vision problems.
What causes cataracts?
Aging and exposure to
sunlight can cause cataracts. Changes in your eyes are often a normal part of
aging. But the changes do not always lead to cataracts.
also happen after an eye injury, as a result of eye disease, after you use
certain medicines, or as a result of health problems such as
Sometimes children are born
What are the symptoms?
Cataracts can affect your
- You may have cloudy, fuzzy, or foggy vision.
may see glare from lamps or the sun. You may have trouble driving at night
because of glare from car headlights.
- You may need frequent
changes to your eyeglasses prescription.
- You may get double vision
in one eye.
- Your near vision may improve for a short time if you
get a cataract. This temporary improvement is called
The vision loss from a cataract often happens slowly
and may never become severe. Sometimes cataracts do not cause any vision problems.
How are cataracts diagnosed?
Your doctor can find
out if you have cataracts by doing a physical exam and by asking questions
about your symptoms and past health. You may need tests to make sure you
have a cataract or to rule out other conditions that may be causing vision
How are they treated?
Surgery can remove cataracts. For most adults, surgery is only needed when vision
loss caused by a cataract affects their quality of life.
There are a number of things you can
do that may help you manage your vision problems. Many people get along very
well with the help of eyeglasses, contacts, or other vision aids. Keep your
eyeglasses or contact lens prescription up to date. Also make sure you have
plenty of lighting in your home. You may be able to avoid or delay
Whether you need cataract surgery depends on how much of
a problem the cataract causes for daily activities like driving and reading.
Surgery is almost always by your choice (elective) and can be scheduled when it
is convenient. For people who decide to have surgery, the surgery usually
works very well.
Some people have to have surgery. Children are
sometimes born with cataracts that need to be removed. Other people may get
cataracts after an eye injury or as a result of eye disease or other health
problems. Cataracts from these causes may also need to be removed.
How can you prevent cataracts?
There is no proven
way to prevent cataracts. But there are some things you can do that may help
slow cataract growth. Don’t smoke. Wear a hat or sunglasses when you are in
the sun. And avoid sunlamps and tanning booths. Eat healthy foods. And keep diabetes under control.
Frequently Asked Questions
Learning about cataracts:
Living with cataracts:
Health Tools help you make wise health decisions or take action to improve your health.
Decision Points focus on key medical care decisions that are important to many health problems.
cataract occurs when the lens inside your eye becomes
cloudy. Things linked to clouding include:
- Aging (age-related cataracts).
- Overexposure to ultraviolet (UV) radiation, such as from sunlight, tanning booths,
- Diabetes. Diabetes, especially when the
blood sugar levels are above the safe range, causes changes in the eye that can
result in cataracts.
- Disease inside the eye, such as
retinitis pigmentosa, retinal detachment, or long-term uveitis.
- Long-term use of
radiation treatments to the head.
- Family history (genetics). A person may inherit the tendency to develop
- Vitrectomy. People who have had the
vitreous gel removed from their eye (vitrectomy) have an increased risk of
- Eye injury. Even though
injury-related cataracts are rare, injury is a leading
cause of cataracts in children.
- Being born with cataracts
(congenital). Some children are born with the condition.
cataracts impair vision or affect daily living. For
those that do, common symptoms include:
- Cloudy, fuzzy, foggy, or filmy
- Glare from lamps or the sun, which may be
- Difficulty driving at night due to glare from
- Frequent changes in eyeglass
- Double vision.
- Improvement of near vision (second sight) that then gets worse.
- Difficulty doing daily activities because of
Parents need to watch for
signs of cataracts in infants and children.
stay small and you may not notice them. They often do not seriously affect
vision. And many cataracts do not need to be removed.
cataracts grow larger or denser over time, causing severe vision
- Severe cataracts can cause loss of independence
for older adults as decreased vision may affect driving, working, reading, or
- While cataracts can cause blindness, this is rare. Surgery
is usually done before a cataract progresses far enough to cause
- A rare type of cataract can lead to
As a cataract progresses, more of the lens becomes cloudy. When the entire lens is white, the cataract is called a
“ripe” or “mature” cataract and causes severe vision problems. Delaying surgery until cataracts are ripe or mature
is neither recommended nor needed.
Cataracts in children are rare but serious. If a cataract prevents light from
entering a child’s eye and stimulating the retina, the area of the brain used
for sight does not develop properly. Usually the child won’t see well with
that eye (amblyopia), even if the cataract is later
What Increases Your Risk
Things that increase your risk for
- Age. Getting older is a
major risk factor for cataracts.
- Family history (genetics). People with a
family history of cataracts are more likely to have
cataracts. People with certain
genetic disorders may also have an increased risk for
Some chronic diseases increase the risk for cataracts.
Keeping these diseases under control may help lower your risk for
People with diabetes are at increased risk for cataracts. Damage to the lens of
the eye results from persistent high blood sugar (glucose) levels.
- Glaucoma. Surgery
to treat glaucoma may raise the risk of cataracts.
Other things that may increase your risk include:
- Smoking. People who smoke are more likely to
develop cataracts. Smoking may damage the lens of the eye by leading to the
formation of chemicals called
free radicals. High levels of free radicals can damage
cells, including those in the lens of the eye.
- Infection during pregnancy. If a woman has certain
infections during pregnancy, such as
chickenpox, the baby may develop a cataract before
- Ultraviolet (UV) light exposure. Ultraviolet B (UVB) is related to cataract development.
- Long-term use and higher doses of steroid medicines. Long-term use of high doses of steroid medicines for
conditions such as
emphysema increases a person’s risk for
When To Call a Doctor
Call your doctor right away if you have:
- Severe eye pain.
- A sudden change in
your vision, such as loss of vision or double vision.
Call your doctor to discuss your symptoms if you:
- Need frequent changes in your eyeglasses
- Have blurred or double vision that develops
- Are having a problem seeing during the daytime because of
- Have difficulty driving at night because of glare from
- Have vision problems that are affecting your ability to
do daily activities.
If you are an older adult, discuss with your doctor how often you need to have routine eye exams.
If a doctor has
not determined that you have cataracts but you have symptoms that concern you,
see the topic
Eye Problems, Noninjury to find more information on what to do about your
Watchful waiting is a wait-and-see approach.
Watchful waiting is safe and appropriate in most cases of adult cataracts. If
you notice signs that your baby or child may not be seeing well, see your doctor. Cataracts in
children should be treated right away.
Speak with an
ophthalmologist about surgery to remove cataracts. In
most cases, you can decide if you want or need surgery based on whether vision
problems caused by the cataract are interfering with your daily
Who to see
The following health professionals can evaluate
vision problems that may be caused by a cataract:
- Nurse practitioner
- Physician assistant
- Family medicine doctor
While other doctors may be able to detect
problems that may be caused by cataracts, only an ophthalmologist can treat
To prepare for your appointment, see the topic Making the Most of Your Appointment.
Exams and Tests
cataracts is based on a
medical history and
Often tests are used
- Confirm the presence of a
- Rule out other conditions that may be causing vision
When you are deciding whether to have
surgery, you may find it very helpful to evaluate the effect that vision loss from a
cataract has on your life. Your doctor may ask you to complete a questionnaire
regarding the effect of the cataract on your daily activities.
already have some vision loss that cannot be corrected by cataract
surgery, your doctor may do a
low-vision evaluation to help find ways for you to
make the most of your remaining vision and to keep your quality of life.
eye exams, your eye doctor will look for early signs of vision
problems, including cataracts.
Testing your child for cataracts may be needed if
you think your child is having a vision problem.
Surgery to remove a cataract is the only way to get rid of a cataract. This surgery works well and helps people see better. But surgery is often not needed or can be delayed for months or years.
Many people with cataracts get along very well with the help of eyeglasses,
contacts, and other vision aids.
Whether surgery is needed for an adult with cataracts depends on the
degree of vision loss and whether it affects quality of life and ability to
The choices for
treating cataracts in children depend on how likely
the cataracts are to interfere with the development of normal vision.
What to think about
Sometimes a cataract needs
to be removed because of another eye disease, such as
diabetic retinopathy or
macular degeneration. In some cases the cataract has
to be removed so that the eye specialist can treat the retina, the nerve layer
at the back of the eye.
Misconceptions about cataracts are common.
More and more medical centers have been built specifically
for cataract surgery. Marketing campaigns aimed at older adults may encourage
some people to have surgery when they do not really need it. Because of fear of
blindness or loss of independence, older adults may think they need to have
surgery even when their cataracts do not affect their quality of life. In many
cases, wearing eyeglasses or contacts and using other vision aids might be
appropriate and just as effective without any of the risks of surgery.
Only you can decide whether a cataract is affecting your vision and your
life enough to have surgery. If surgery is not going to improve your vision,
you may decide that surgery is not for you.
There is no proven way to prevent
cataracts. But certain lifestyle habits may help slow
cataract development. These include:
- Not smoking.
- Wearing a hat or
sunglasses when you are in the sun.
- Avoiding sunlamps and tanning booths.
- Eating healthy foods.
- Avoiding the use of
steroid medicines when possible (some people need them).
diabetes under control.
If you have
cataracts, these tips and vision aids may help you
manage your vision problems and avoid or delay surgery:
- Tips for improving vision include using a soft background light plus a light on your task, avoiding glare on TV and computer screens,
and keeping your eyeglass or contact lens prescription up to
- Low-vision accommodations in your home, such as using
adequate lighting and adjusting carpets and furniture to avoid potential
hazards, can make living with low vision easier and safer. For more
information, see the topic
Preventing Falls in Older Adults.
- Low-vision aids and adaptive technologies such as
video enlargement systems or speech software for computer systems can help
people who have impaired vision make the best use of their remaining vision.
Evidence shows that making certain lifestyle changes
such as not smoking and protecting your eyes from sunlight may help slow the
development of cataracts.
After cataract surgery
Your doctor will give you
instructions about what to do after cataract surgery.
Eye care for adults after cataract surgery includes using prescribed
eyedrops, protecting your eye, and watching for signs of infection.
Contact your doctor promptly if you notice any signs of complications,
- Decreasing vision.
- Increasing redness.
- Swelling around the
- Any discharge from the eye.
- Any new
flashes of light, or changes in your field of
It is normal to have blurred vision and some swelling
after surgery. It takes time for the swelling to go down. Your eyeglass
prescription may change after surgery.
A small number of adults and children with
cataracts may benefit for a short time from eyedrops
that widen (dilate) the pupil. These eyedrops increase the amount of light
getting into the eye. They are sometimes used to help prevent
vision loss in very young children who need to wait for surgery to be done.
What to think about
There is currently no medicine
that will cure cataracts.
Surgery for cataracts involves removing the clouded lens of the eye
(the cataract). The lens can be replaced with an artificial lens called an
intraocular lens implant (IOL). Or, if an IOL cannot be used for any reason, it
will be left out and contact lenses or, in rare cases, eyeglasses can compensate for
its absence. Most people will get an IOL during surgery.
surgery, ask your doctor about what types of IOLs can go in your
eye. Or, if you will not be getting an IOL, find out why, and ask
about the pros and cons of contact lenses or eyeglasses.
Options to help you see better after surgery
- Intraocular lens (IOL). A variety of IOL
types are available. Work with your doctor to choose the best
one for you.
- Contact lens. You will need to
insert, remove, and clean the lenses on a regular basis. A contact
lens may not be a good choice for young children or older adults who have a
hard time properly placing the lens on the eye.
- Cataract glasses. Cataract glasses were used for
decades when there were no other options for lens replacement. Because they are
thick and heavy, they are rarely used now.
For most adults, surgery is only needed when vision
loss caused by a cataract affects your quality of life. The goals of surgery in
adults who have cataracts include:
- Improving vision.
- Helping you
return to work, leisure, and other daily activities.
The choices for
treating cataracts in children depend on how likely
the cataracts are to interfere with the development of normal vision. Surgery for
cataracts in children may be needed.
For adults who have cataracts in
both eyes, surgery is not normally done on both eyes at the same time. The
first eye needs to heal. Then your doctor will determine how much eyesight has
improved before surgery is done on the second eye.
There are two main types of
cataract surgery. They are both done in an
outpatient center. The decision about which
one to use depends on what kind of cataract you have and how much experience
the surgeon has with each type of surgery.
- Phacoemulsification (small-incision surgery). In this type of surgery, the
incisions are small, and sound waves (ultrasound) are used to break up the lens
into small pieces. This is the most common method of doing cataract
surgery. Your doctor may use a laser to help with part of this surgery.
- Standard extracapsular cataract extraction (ECCE). In this type of surgery,
the lens and the front portion of the lens capsule wrapped
around the lens is opened. The lens is then carefully removed in one piece.
The most common problem after cataract surgery is clouding of the posterior lens capsule
(called aftercataract) within 5 years after surgery. This clouding is
usually not a serious problem. And it is easy to treat with a laser surgery
(Nd:YAG laser posterior capsulotomy) if it occurs.
What to think about
Just because you have a cataract doesn’t mean you
need to have it removed. Only you can decide whether cataracts are affecting
your vision and your life enough for you to have surgery. Learn
what to ask about cataract surgery before deciding whether to have the
For adults, cataract surgery is
almost always elective and can be done at your convenience. The surgeon, or
someone familiar with routine surgical practices, will usually be available for
any follow-up exams and treatment.
Surgery may be advisable if you want to continue to
drive a car. If you live in a retirement home or assisted-living facility, you
may decide to use vision aids and avoid surgery.
If you do not have another eye
condition, such as glaucoma or problems with your
retina, your chances of seeing better after cataract
surgery are very good. But you may still need reading glasses or glasses for
Other Places To Get Help
Other Works Consulted
- Awasthi N, et al. (2009). Posterior capsular opacification. Archives of Ophthalmology, 127(4): 555-562.
- Harper RA, Shock JP (2011). Lens. In P Riordan-Eva, JP Whitcher, eds., Vaughan and Asbury’s General Ophthalmology, 18th ed., pp. 174-182. New York: McGraw-Hill.
- Long V, et al. (2007). Surgical interventions for bilateral congenital cataract. Cochrane Database of Systematic Reviews (1).
- Mathew MC, et al. (2012). Antioxidant vitamin supplementation for preventing and slowing the progression of age-related cataract. Cochrane Database of Systematic Reviews (6).
- Wright KW (2008). Leukocoria: Cataracts, retinal tumors, and Coats disease. In Pediatric Ophthalmology for Primary Care, 3rd ed., pp. 285-310. Elk Grove Village, IL: American Academy of Pediatrics.
Primary Medical Reviewer Kathleen Romito, MD – Family Medicine
Adam Husney, MD – Family Medicine
Specialist Medical Reviewer Carol L. Karp, MD – Ophthalmology
Current as ofApril 7, 2017