What Are Cataracts?
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Medically reviewed by Christine L. Larsen, MD
Cataracts are opaque or cloudy regions of the (normally clear) lens of the eye. Overall, about 24.4 million people in the United States are affected by cataracts, making this the most common cause of visual problems.
Older age raises your chances of developing this condition; more than half of people with cataracts are between 65 and 74 years of age. In addition, certain risk factors increase your risk of developing cataracts, including being assigned female at birth, having a family history of the condition, as well as certain health conditions, including diabetes, high blood pressure, obesity, and others.
Cataract symptoms can vary based on the type you have. It usually affects both eyes, causing clouded or blurry vision, loss of brightness in colors, and difficulty seeing at night, among other visual disturbances. Treatment options for cataracts range from making adjustments to your home environment to changing glasses or contact prescriptions to surgery. Fortunately, cataracts are highly treatable, with most people seeing improvements in their vision.
Types
The lens of your eye, which sits behind the colored portion, or iris, is composed of multiple layers. Cataracts are categorized based on the layer of the lens that’s affected. There are three major types: nuclear, cortical, and posterior capsular.
Nuclear Cataract
This type occurs when there’s clouding or discoloration of the inner, central part, or nucleus, of your lens. Nuclear cataracts tend to get worse gradually, affecting your long-distance vision more than your ability to see things close by.
Cortical Cataract
The cortex of your lens is a layer that surrounds the nucleus. Cataracts here, known as cortical cataracts, tend to have a spoke-like appearance or look like drops of oil. They tend to spread from the edges of the lens toward the center. Glare from bright objects is a prominent issue if you have this type.
Posterior Capsular Cataract
A posterior capsular cataract occurs when the back (posterior) of the outer layer, or capsule, of your lens is affected. Extensive vision loss can happen if blurriness and discoloration affect the central part of the capsule. Common signs include experiencing glare and poor vision during bright light.
Cataracts Symptoms
Generally, cataracts are a progressive issue, meaning you may not notice symptoms at first, but they get worse over time. Depending on your case, this can be a rapid or slow process, and there may be differences based on the type of cataract you have. One or both eyes may be affected.
The typical signs of cataracts include:
Visual interruptions: Cloudiness and blurriness in your field of vision are hallmarks of the condition; this may start in one part of your vision and then grow and spread.
Faded colors: The colors you see may have a faded or yellow-tinged appearance due to discoloration and opacity in your lens.
Affected night vision: This is characterized as a progressive loss of ability to see in the dark or at night. You may need brighter lights to read at night, and your ability to drive may be affected.
Light sensitivity: The light or glare from the sun, lightbulbs, lamps, or headlights may feel too bright.
Halo: A circular “halo” may appear around lights that you see.
Double vision: Some may see double or perceive a “ghost-like” second image of something they look like next to the original.
Loss of visual accuracy: The worsening ability to see clearly far away and/or nearby can arise; if left untreated, cataracts can lead to blindness.
What Causes Cataracts?
The lens of your eye is made of certain proteins, called crystallins, which are finely arranged to focus light to a layer of vision nerves (the retina) in the back of the eye. A cataract arises as the structure of these crystallins starts to break down, and they start to group together. The visual effects of cataracts occur as light entering the eye is scattered or altered by these groupings, which form into opaque or discolored patches.
Primarily, cataracts are the natural result of aging. As you get older, your body starts to lose its ability to remove waste and toxins and repair cells. In the lens of the eye, this natural progress causes the structure of the crystallins to be affected, and cataracts form. Genetics and other health factors or diseases may induce this process.
Risk Factors
Alongside older age, certain diseases, health conditions, and other factors increase your chances of developing cataracts. These include:
Family history of cataracts
Being assigned female at birth
Taking corticosteroids, such as cortisone or Prednisone Intensol (prednisone)
Taking phenothiazine medications, especially Thorazine (chlorpromazine)
Exposure to ultraviolet (UV) radiation
Smoking
Alcohol use
Diagnosis
The primary goals of diagnosis are two see how severe the cataracts are and to make sure any symptoms aren’t being caused by anything else. Diagnosis involves assessing your medical history, any medications you’re taking, and a complete ophthalmic (eye) exam. Further testing may help rule out other eye conditions like glaucoma, chronic conjunctivitis, and diabetic retinopathy, among others.
Your healthcare provider (usually an optometrist or ophthalmologist, two types of eye doctors) may perform the following diagnostic tests:
Snellen chart: This is the primary test of visual ability (known as “acuity”); it involves checking your ability to read letters off of a chart. Your vision may also be tested under brighter light testing to assess the impact from glare.
Refraction test: To assess the strength of the glasses you need, you’ll be asked how clear an image looks and how well you can see using a series of different lenses.
Slit lamp exam: An eye doctor closely analyzes the surface of your eye using a microscope to assess the scope of the issue and plan treatment.
Intraocular pressure test: Using a special device, a puff of air is applied to the outer layer (cornea) of the eye to assess the amount of pressure inside the eye; this can help rule out glaucoma.
Dilated eye exam: Drops are used to dilate your eyes, allowing the eye doctor to see your retina. This is another test that can detect glaucoma and other eye conditions.
Funduscopic exam: This is a careful examination of the retina and inside of the eye using a microscope and light device called an ophthalmoscope.
Optical biometry: This involves using instruments to assess the curvature and shape of your eye prior to surgery.
Macular function test: This eye test assesses the health of the macula, a part of the retina, to determine how well cataract surgery is expected to work.
Ultrasound: This is a form of imaging that relies on sound waves. Your eye doctor may call for an ultrasound to rule out a detached cornea or other potential causes of ocular symptoms.
Treatments for Cataracts
Treatments for cataracts focus on restoring vision and clearing up any vision problems. Depending on the case, your provider may try non-surgical approaches before opting for cataract surgery.
Cataract Surgery
If the cataracts are causing significant vision issues and getting in the way of your ability to read, drive, or perform daily tasks, your eye doctor may call for surgery. The primary surgical approach is called phacoemulsification. This surgery uses a device to transmit ultrasound waves via a small incision in the eye. These waves weaken the lens so it can be removed and replaced with an artificial lens (known as an intraocular lens or IOL).
Another approach is extracapsular surgery, which relies on a larger incision to remove the entirety of the affected lens. An IOL is then implanted in your eye, or contact lenses or special glasses can be used to correct vision.
Non-Surgical Approaches
If the impact of the cataracts is minimal and the progress of the condition is slow, your condition may be observed and non-surgical approaches considered. You may get new prescriptions for your glasses or contacts to help with vision loss.
Prevention
While some cases of cataracts can’t be prevented, making certain lifestyle changes and other measures may help. Prevention strategies include:
Eating a healthy, nutritious diet that’s high in vitamins E, C, and zinc and fresh foods
Regular physical activity
Not smoking
Protecting your eyes from the ultraviolet B (UVB) rays in direct sunlight
Managing chronic conditions, such as diabetes or high blood pressure, which can contribute to the development of cataracts
Related Conditions
Certain eye and systemic health conditions are more likely to arise if you have cataracts. Such related conditions include both eye issues and those affecting other parts of the body. Vision problems often seen alongside cataracts include:
Glaucoma: Characterized by increased pressure inside the eye, glaucoma was found in the research to affect between 9.2% and 31.3% of people with cataracts.
Diabetic retinopathy: Damage to the retina due to diabetes, or diabetic retinopathy, was seen in between 4.1% and 9% of cataract patients.
Macular degeneration: An eye disease that causes blurriness in the central part of your vision, macular degeneration arose in about 10% of those with cataracts.
Pseudoexfoliation syndrome: A disorder in which dandruff-like flakes build up in the eye, pseudoexfoliation syndrome can lead to glaucoma and worsen cataract cases.
Myopia and hyperopia: Near-sightedness, or myopia, and far-sightedness (things further away are clearer) or hyperopia also arise due to the effects of cataracts on the lens.
In addition to eye problems, systemic diseases also frequently accompany cataracts, including:
Diabetes mellitus: Causing an inability to digest sugars, diabetes mellitus is often associated, with research finding this condition in about 60% of those with cataracts.
Hypertension: Researchers have found high blood pressure, or hypertension, to occur in 62.8% of people with cataracts.
Chronic kidney disease: A condition that causes the kidneys to be unable to filter blood, chronic kidney disease was found in 5.3% of those seeking cataract surgery.
Coronary artery disease: Causing arteries in the heart to harden and affecting blood flow, one study found coronary artery disease in 4.8% of cataract surgery patients.
Asthma: Asthma causes difficulty breathing; the chances of developing this issue was found to be 36% higher if you have cataracts.
Human immunodeficiency virus (HIV): HIV is a viral infection that attacks the immune system; it’s thought that because of its impact on immunity, the risk of cataracts is elevated, and the two conditions often occur at the same time.
Living With Cataracts
Worldwide, cataracts are the number one cause of preventable blindness, an issue that is more common in low to middle-income countries. That said, treatments are highly effective, with surgery having excellent results (prognosis) 70 to 80% of the time. Even with surgery, you may still require glasses or contacts to help you see.
Timely care and regular check-ups are critical in the management of cataracts. If you suspect you have cataracts or are experiencing vision problems impacting your ability to function independently, be sure to get your eyes checked. The sooner you get help, the better off you’ll be.
Frequently Asked Questions
Is a cataract considered a disability?
According to the Social Security Administration, vision problems qualify for disability benefits when your vision can’t be corrected to better than 20/200. This means that the visual impairment makes something 20 feet away as clear as it would be at 200 feet away with healthy eyes. Cataracts can get to this point, especially if untreated, so it can sometimes be considered a disability.
Can you drive safely with cataracts?
Your vision may not be significantly affected In the early stages of cataracts. Glasses and contacts will typically be able to manage it. In absence of other diseases and if there are few effects on your ability to see, your healthcare provider may decide it’s OK for you to drive. However, if they get worse, then it may be unsafe to do so. Be sure to talk to your doctor before deciding whether you can drive safely.
What is the average age for cataract surgery?
Cataracts often arise as a natural consequence of aging, so those who get cataract surgery tend to be older. According to one study published in 2018, in the US, the average age of the surgery patient was 67.7 years.
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