What Are Cataracts?

Cataracts are the leading cause of vision loss among people over age 55. They can make your vision appear fuzzy or blurry, as if you are looking through a fogged-up window. Cataracts can develop due to normal aging. Additionally, risk factors such as diabetes and smoking can also predispose you to cataracts. Treatment can range from wearing customized eyewear and improving the lighting in your home to surgical removal of the cataract, which may include replacement of the lens in your eye.

Types of Cataracts

The lens consists of three layers: the outer layer (capsule), the middle layer (cortex) and the inner layer (nucleus). There are three different types of cataracts, distinguished by the part of the lens affected.

Nuclear Sclerotic Cataracts

This is the most common type of age-related cataract, and it causes gradual yellow cloudiness and hardening of the nucleus of the lens. Changes in vision are usually gradual.

As a nuclear sclerotic cataract develops, you may experience an improvement in your near vision before your vision deteriorates. Referred to as "second sight," this stage is usually only temporary.

Cortical Cataracts

Diabetes is one of the leading risk factors for developing a cortical cataract. The cataract generally appears as a whitish, cloudy opacity in the cortex of the lens.

These cataracts often resemble wheel spokes, pointing toward the front and center of the lens. Light tends to scatter when it hits the spoke-like opacities.

Posterior Subcapsular Cataracts (PSCs)

These cataracts form in the back of the lens and usually affect one eye more than the other. PSC is an opacity that develops on the back surface of the lens.

This type of cataract causes light sensitivity, blurred near vision, and glare and halos around lights. It is more common among people who have diabetes or who have taken steroids for extended periods of time.

Cataract Symptoms

Cataracts can develop in one or both eyes. They are painless and don't cause any changes in the appearance of your eyes. Vision is not usually affected early on when cataracts are small, but they usually worsen over time and can cause a gradual deterioration of sight.

The most common symptoms of cataracts include:

• Blurred vision
• Light sensitivity
• Seeing halos around lights
• Impaired night vision
• Yellowing or fading of color vision
• Double vision
• Altered depth perception

Most older people develop some degree of lens clouding, which is a normal part of aging. However, if a cataract if left untreated (such as in a place where cataract surgery is not readily available) it can eventually lead to complete blindness.

Causes

A cataract affects the lens of the eye, a transparent structure that is mostly made up of water and protein fibers. The lens is responsible for focusing light and producing clear, sharp images.

The entire lens is contained within a lens capsule. As the eyes age, protein and dead cells accumulate there, forming a cataract and causing the lens to become cloudy. Early on, a cataract may be a small, opaque spot. Over time, it may grow larger and cloud a bigger portion of your lens, making it harder for you to see.

With a cataract, the light that would normally be focused by the lens is scattered around because of the cloudiness, so vision is no longer clear and sharp.

Risk Factors

The biggest risk factor for developing cataracts is aging. Other risk factors include:

• Diabetes
• Eye surgery
• A family history of cataracts
• Smoking
• Certain medications, such as steroids and statins (a type of cholesterol-lowering medication)
• UV exposure
• Radiation
• Eye trauma
• Congenital (present from birth or during early childhood)

Diagnosis

Your healthcare provider can perform a number of vision tests and detailed eye examinations to help diagnose a cataract. Usually, an ophthalmologist or an optometrist must do these tests for you because they have experience with visual assessment and some of the tests require special equipment.

Tests you may need if you have a possible cataract include:

• Visual acuity test: Your eye doctor will measure the sharpness of your vision by having you read letters on a chart from a distance.
• Contrast sensitivity testing: This is an assessment of your ability to detect visual contrast, which can be altered due to glare caused by your cataract. Eye doctors consider contrast sensitivity testing to be a valuable measure of the quality of your vision.
• Slit lamp exam: A slit lamp exam uses light and a microscope to examine the structures of your eye in detail. Your healthcare provider will ask you to place your chin on a chin rest. A light will then be directed at your eye. By looking through the slit lamp, especially when your pupil is dilated with eye drops, your practitioner can see the cataract and other eye problems.
• Retinal exam: Using an ophthalmoscope, your healthcare provider can carefully examine the inside of your eyes. This examination is typically used to examine the optic nerve and retina, but the lens can be visualized as well. Your practitioner may use eye drops to dilate your pupils.
• Tonometry test: This examination measures the pressure inside your eye, often using a small probe placed directly on the eye or an air puff test. While this test is not specifically designed to assess cataracts, it can identify other eye problems that cause visual deterioration, such as glaucoma.
• Potential acuity test (PAM): This test measures how well you would see if you did not have a cataract. This helps you and your healthcare provider know whether cataract surgery would improve your vision. A PAM test projects a visual acuity eye chart into the eye with a laser, by-passing the cataract. You can read the chart the same way you would read an eye chart on the wall. If your vision is read as 20/40 using a PAM exam, cataract surgery would be expected to give you 20/40 vision from that eye.

Treatment

Cataracts that are small and do not have a major impact on vision generally do not require treatment. Wearing corrective glasses with a different prescription, using artificial tears, tinting lenses to reduce glare, and using sunglasses can help with many of your symptoms.

Surgery is the only cure for cataracts, but getting diagnosed does not mean you immediately need such a procedure. Many people live with mild cataracts for years. However, if your cataract is causing substantial vision loss, there is no benefit to waiting before surgery. Advanced cataracts also carry a higher risk of complications during surgery.

Cataract Surgery

Cataract surgery involves removing the clouded lens and possibly replacing it with an artificial lens implant.

Cataract surgery is usually performed on one eye at a time. This is done to minimize potential complications. It is usually an out-patient procedure, and you should expect to go home on the same day.

There are a few types of cataract surgery, and the best procedure for you depends on the size and location of your cataract.

• Phacoemulsification: Sometimes called phaco- or small incision cataract surgery, this is the most common type of cataract removal procedure. A device vibrating at a high speed is inserted into the eye through a tiny incision. This device emits ultrasound waves that carefully soften and break up the lens, so it can removed by suction. An artificial lens can then be inserted into the eye. Only one stitch (or none at all) may be required to close the wound.
• Extracapsular cataract surgery: This procedure is similar to phacoemulsification, but a larger incision is made so that the lens can be removed in one piece. Several stitches or sutures may be required to close the wound. Healing is generally slower than with small incision cataract surgery, and complications such as astigmatism can occur.
• Intracapsular cataract surgery: The entire lens and its capsule can be removed through a large incision. This method is generally reserved for large cataracts or eye trauma and can result in more complications and slower healing than surgeries that involve a smaller incision.
• Laser cataract surgery: This uses a femtosecond laser, which produces a magnified, high-resolution image with a built-in optical coherence tomography (OCT) device. The laser creates an incision, the lens is broken into small pieces, and a phaco piece is inserted to remove the lens fragments. Then, a new intraocular lens can be implanted.

How It's Done

While there are variations depending on the type of cataract surgery being performed, here's what you can generally expect:
Before your surgery, you may be given a mild sedative and you will have eye drops placed in your eye to dilate your pupil. The skin around your eye and eyelid will be cleaned and sterilized. A sterile drape will be placed over your head and around your eye. Anesthetic eye drops are then applied.

Tiny incisions will be made in the peripheral part of your cornea, the clear dome-like structure on the front part of your eye. Next, the capsule will be opened. A small ultrasonic probe will be inserted into your eye. This probe will dissolve the cataract and the remaining material will be suctioned out.

If planned for, a new, clear lens implant can then be inserted into your eye through the same small incision and positioned into place.

Recovery

It is OK to read, write, or watch television right after your surgery, but you should wear sunglasses for the first few weeks when you are exposed to light, even indoors.

Most people have some inflammation after cataract surgery, which can make your eye feel slightly gritty or scratchy for the first few days. Your vision may be blurry due to the inflammation, pupil dilation, and antibiotic ointment.

You will be given a prescription and instructions for eye drops to use for the next couple of weeks after surgery. These eye drops are used to prevent infection and to manage inflammation.

You should avoid touching and rubbing your eye. You'll be instructed to wear an eye patch your first night after surgery to protect your eye. You should avoid bending over and lifting heavy objects for the first week or two following surgery.

Your healthcare provider will most likely ask you to come in for several follow-up visits to monitor your recovery. After your first post-operative visit, you may be advised to wear a night guard patch for the next several nights.

Possible Complications

Cataract surgery is a safe procedure with very few complications. However, as with any surgery, post-operative problems may develop.

Complications to look out for include:

• Infection: An infection directly after cataract surgery can be very serious and is considered an eye emergency. If you have pain or redness, call your healthcare provider right away.
• Inflammation: Some inflammation is expected after cataract surgery. Inflammation can cause light sensitivity, pain, or achy eyes.
• Swelling: Swelling in the back of the retina can occur. Although it requires attention, this usually resolves within a month or so.
• Retinal detachment: If you see spots, floaters, or flashes of light, call your healthcare provider.
• Posterior capsular haze: The capsule behind the new lens implant can thicken and become hazy 20% to 40% of the time after cataract surgery, making your vision blurry. This common complication can occur months or years after surgery. A laser procedure known as Yag capsulotomy can remove this hazy capsule.

Prevention

There are no specific medications or therapies used for cataract prevention, but several strategies can reduce your risk.

Controlling your diabetes, not smoking, and wearing sunglasses can help prevent cataracts from developing or from worsening if you already have them.

Consuming antioxidants and omega-3 fatty acids is associated with a lower risk of cataracts. This may be related to the actions of these dietary components, which neutralize harmful substances in the body.

A Word From Verywell

If you have blurry vision, it is important to schedule a comprehensive eye examination to determine the cause. Cataracts may be causing your vision problems, but other eye diseases can cause clouded vision as well. Your eye doctor will perform several diagnostic tests to check the overall health of your eyes. Many eye problems can be prevented or corrected if detected early.