What are cataracs?

Inside our eyes, we have a natural lens. The lens bends (refracts) light rays that come into the eye to help us see. The lens should be clear but can become more opaque with time.

Picture of a person with cataracts.

A cataract is when your eye’s natural lens becomes cloudy. Proteins in your lens break down and cause things to look blurry, hazy or less colorful. When you have cataracts, it is like looking through a foggy or dusty car windshield.

What Are the Symptoms of Cataracts?

Cataracts cause changes in your vision. Changes you may notice include:

-Having blurry vision

-Seeing double (when you see two images instead of one) or a ghosted image out of the eye with cataract

Image courtesy of American Academy of Ophthalmology

-Being extra sensitive to light (especially with oncoming headlights at night)

-Having trouble seeing well at night, or needing more light when you read

-Seeing bright colors as faded or yellow instead

Image courtesy of American Academy of Ophthalmology

If you notice any of these cataract symptoms, notify your ophthalmologist.

What Causes Cataracts?

Aging is the most common cause. After age 40, normal proteins in the lens start to break down. This is what causes the lens to get cloudy. People over age 60 usually start to have some clouding of their lenses. However, vision problems may not happen until years later.

Other reasons you may get cataracts include:

  • having parents, brothers, sisters, or other family members who have cataracts
  • having certain medical problems, such as diabetes
  • smoking
  • having had an eye injury, eye surgery, or radiation treatments on your upper body
  • having spent a lot of time in the sun, especially without sunglasses that protect your eyes from damaging ultraviolet (UV) rays
  • using certain medications such as corticosteroids, which may cause early formation of cataracts

While most cataracts are age-related, some children are born with cataracts or develop them after birth.

How Are Cataracts Diagnosed?

Your ophthalmologist will examine and test your eyes to make a cataract diagnosis. This comprehensive eye exam will include dilation. This means eye drops will widen your pupils.

Slit-lamp Exam

Your ophthalmologist will examine your cornea, iris, lens and the other areas at the front of the eye. The special slit-lamp microscope makes it easier to spot abnormalities.

Retinal Exam

When your eye is dilated, the pupils are wide open so the doctor can more clearly see the back of the eye. Using the slit lamp, an ophthalmoscope or both, the doctor looks for signs of cataract. Your ophthalmologist will also look for glaucoma and examine the retina and optic nerve.

Refraction and Visual Acuity Test

This test assesses the sharpness and clarity of your vision. Each eye is tested individually for the ability to see letters of varying sizes.

Once I have a Cataract Diagnosis, What should I do?

  • Have an eye exam every year if you’re older than 65, or every two years if younger.
  • Protect your eyes from UV light by wearing sunglasses that block at least 99 percent UV and a hat.
  • If you smoke, quit. Smoking is a key risk factor for cataracts.
  • Use brighter lights for reading and other activities. A magnifying glass may be useful, too.
  • Limit driving at night once night vision, halos or glare become problems.
  • Take care of any other health problems, especially diabetes.
  • Get the right eyeglasses or contact lenses to correct your vision.
  • When it becomes difficult to complete your regular activities, consider cataract surgery.
  • Make an informed decision about cataract surgery. Have a discussion with your ophthalmologist about: the surgery, preparation for and recovery after surgery, benefits and possible complications of cataract surgery, cataract surgery costs, and other questions you have.

How Are Cataracts Treated?

Cataracts can only be removed with surgery. If your cataract symptoms are not bothering you very much, you don’t have to remove a cataract. You might just need a new eyeglass prescription to help you see better. You should consider surgery when cataracts keep you from doing things you want or need to do.

How Does Cataract Surgery Work?

The eye surgeon will remove your eye’s cloudy natural lens. They will replace it with an artificial lens, called an intraocular lens (or IOL).  Most IOLs are made of silicone, acrylic, or other plastic compositions. They are also coated with a special material to help protect your eyes from the sun’s harmful UV rays. There are several types of IOLs. When you decide to have cataract surgery, your doctor will talk with you about IOLs, how they work, and which type is best for you.

The most common type of cataract surgery is called phacoemulsification. During this process, the rapidly vibrating tip of an ultrasound probe breaks up the cataract. Your surgeon then suctions out the lens, as seen in the top image. An outer housing of the cataract, called the lens capsule, is generally left in place. After removing the lens, your surgeon places the lens implant into the empty space within the capsule where the natural lens used to be, as seen in the bottom image.

What Can I Expect With Cataract Surgery?

Before Surgery:

  • Your surgeon will measure your eye to determine the proper focusing power for your IOL.
  • You will be asked about any medicines you take. You might be asked not to take some of these medicines before surgery.
  • You may be prescribed eye-drop medicines to start before surgery. These medicines help prevent infection and reduce swelling during and after surgery.

The Day of Surgery:

Cataract removal surgery may be done in an outpatient surgery center or in a hospital. Here is what will happen:

  • Your ophthalmologist may ask you not to eat any solid food at least 6 hours before your surgery.
  • Your eye will be numbed with eye drops or with an injection around the eye. You may also be given medicine to help you relax.
  • You will be awake during surgery. You may see light and movement during the procedure, but you will not see what the doctor is doing to your eye.
  • Your surgeon looks through a special microscope. They create tiny incisions (cuts, created by blade or a laser) near the edge of your cornea. The surgeon uses these incisions to reach the lens in your eye. Using very small instruments, they will break up the lens with the cataract, e.g., with an ultrasound instrument (phacoemulsification) and remove it. Then they put your new lens into place.
  • Usually, your surgeon will not need to stitch the incisions closed. These “self sealing” incisions will close by themselves over time. A shield will be placed over your eye to protect it while you heal from surgery.
  • You will rest in a recovery area for about 15–30 minutes. Then you will be ready to go home.

Days or Weeks After Surgery:

  • You may have to use eye drops after surgery. Be sure to follow your doctor’s directions for using these drops.
  • Avoid getting soap or water directly in the eye.
  • Do not rub or press on your eye. Your ophthalmologist may ask you to wear eyeglasses or a shield to protect your eye.
  • You will need to wear a protective eye shield when you sleep.
  • Your ophthalmologist will talk with you about how active you can be soon after surgery. They will tell you when you can safely exercise, drive or do other activities again.

What are the risks of cataract surgery?

  • Eye infection
  • Bleeding in the eye
  • Ongoing swelling of the front of the eye or inside of the eye
  • Swelling of the retina (the nerve layer at the back of your eye)
  • Detached retina (when the retina lifts up from the back of the eye)
  • Damage to other parts of your eye
  • Pain that does not get better with over-the-counter medicine
  • Blurred vision
  • Seeing halos, glare, and dark shadows
  • Vision loss
  • The IOL implant may become dislocated, moving out of position

Cataract surgery will not restore vision lost from other eye conditions such as macular degeneration, glaucoma, or diabetic retinopathy. Your ophthalmologist will talk with you about the risks and benefits of cataract surgery.

What is the Latest Research on Cataracts?

1. University of East Anglia researchers have made an advance in ocular device technology with the introduction of a novel resin for 3D printing intraocular lenses (IOLs). This innovation has the potential to enhance the manufacture of eye implants universally used in cataract surgery. “While still in the early stages, the ability to 3D print these lenses could significantly enhance eye care for patients by offering unprecedented levels of customization and design precision, potentially leading to better clinical outcomes,” the authors said. In addition, 3D printing could improve speed and precision in manufacturing.

2. There are currently no permanent nonsurgical options for treating cataracts. Future options may include eye drops, as some eye drops work to dissolve cataracts. Researchers have developed a new medication that utilizes a naturally occurring steroid called lanosterol. This steroid has shown potential in preventing the clustering of flawed crystallin proteins that lead to cataracts in the non-congenital form of the disease. The next step for the scientists is to determine the precise mechanism behind how the lanosterol-based eye drops work and to conduct further research through human trials. This discovery could revolutionize how cataract treatments are conducted, offering a promising alternative to surgery.

Gene therapies also hold promise as a future innovation for treating cataracts. Gene therapy is a cutting-edge approach that aims to address genetic mutations responsible for various illnesses in patients. Gene therapy strives to replace or repair defective genes by introducing fresh genes into the body. Studies have revealed that specific genes play a crucial role in the formation of cataracts in both humans and rodents. Any disruption in the expression of these genes can significantly contribute to the onset of severe cataracts in both humans and mice. Such findings highlight the importance of these genes in maintaining proper lens function and preserving visual acuity. While more research is needed on gene therapies for cataracts, the discovery of these genes and the success of gene therapies for other eye disorders provide hope for those facing vision impairment due to cataracts.


Boyd, Kierstan. “What Are Cataracts?” American Academy of Ophthalmology, 16 Oct.  2023, www.aao.org/eye-health/diseases/what-are-cataracts

Boyd, Kierstan. “Cataract Surgery: Risks, Recovery, Costs.” American Academy of Ophthalmology, 15 Nov. 2023, www.aao.org/eye-health/diseases/what-is-cataract-surgery

“Cataracts.” Mayo Clinic, Sep. 28, 2023, https://www.mayoclinic.org/diseases-conditions/cataracts/symptoms-causes/syc-20353790 and https://www.mayoclinic.org/diseases-conditions/cataracts/diagnosis-treatment/drc-20353795

University of East Anglia. “Innovative 3D printing could improve treatment for cataracts and other eye conditions.” Medical Xpress, 19 May, 2024, https://medicalxpress.com/news/2024-05-3d-treatment-cataracts-eye-conditions.html

William A. Haseltine, “Shedding New Light on Cataract Care.” Forbes, 5 Oct. 2023, https://www.forbes.com/sites/williamhaseltine/2023/10/05/shedding-new-light-on-cataract-care/?sh=6a38e81a4252

Compiled/edited by M. Kaplan, PhD, 5/2024

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