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Intraocular Lens (IOL) Implants, Lenses & Types

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Cataracts affect your vision because they cloud the lens of your eye. Surgery is the typical course of action for most people, and this often means you will have your lens removed and replaced by an intraocular lens (IOL) implant.

The type of intraocular lens implanted will vary depending on your case and vision. IOLs refocus light in your eye to help you see better.

Like any surgery, an IOL implant comes with some risks. Your doctor will assess if it is the right course of action for your situation.

When Are Intraocular Lens Implants Used?

Your eye contains a lens, or thin layer, that allows light to bend so you can see properly. Generally, due to aging or eye injuries, cataracts can form. They cause cloudiness in the lens that makes everyday activities more difficult.

Surgery is the traditional course of action for cataract patients. The patient’s lens is removed, and an IOL is inserted to help them see better.

The surgery is done by an ophthalmologist. It tends to be an outpatient procedure that does not require a hospital stay.

What Are IOLs?

Intraocular lenses were first developed in 1949 by British ophthalmologist Sir Harold Ridley in consultation with John Pike, an optical expert for the Rayner Optical Company. Cataract surgery already existed then, but there were no replacements for the lens that was removed.

They determined that perspex, a material used to build windows for the Royal Air Force during World War II, would be used. This is because airmen who were injured after this glass shattered did not experience inflammation, and that meant there was a possibility that this material would be compatible with the eye.

Materials for IOLs changed over the years, and updates to the surgery are continually made. Surgeries became more common in the 1970s, and they really took off in the 1980s. Today, cataract surgeries and placement of IOLs are safe, minimally invasive, and effective procedures.

Two female friends with surfboards

Types of IOLs

Your doctor will check your vision before surgery because IOLs come in various focusing powers. They may be made of various materials, such as acrylic, silicone, and other types of plastic. All IOLs are coated to protect your eye from UV rays.

To decide which type of IOL you will use, your doctor will measure the curve in your cornea and your eye length. The following types of intraocular lens implants are available:

  • Monofocal IOLs: These are for people who have good vision. People who do not need glasses or who only need them for certain tasks are most likely to get this type of IOL. A monofocal IOL only has one focusing distance: close, medium, or distance. It is common to need glasses for closer distances, such as working on a computer or tasks that require a lot of detail.
  • Multifocal IOLs: These IOLs have more than one focusing distance. They have different focusing strengths to let you see objects clearly at different distances. People who have used multifocal glasses or who would be candidates for these types of glasses are most like to get this IOL. If you do end up with this IOL, you will likely have a laser cataract procedure to help with fit.
  • Toric IOLs: These are usually for people who have astigmatism, a condition that features uneven arc or curvature in their lens or cornea. A toric IOL can compensate for refraction issues, allowing you to see better after surgery is over. Doctors make temporary marks to the cornea to guide them during surgery. Toric IOLs also come with alignment tags that guide your doctor. The lens is aligned with markings on the eye to correct astigmatism as best as possible.
  • Accommodating IOLs: These lens implants change or move the eye’s shape to help patients see better. Their design is aspherical; they are not shaped like a sphere or cylinder. Accommodating IOLs also have flexible “haptics” or small legs that allow the new lens to move. This means that if you look at objects that are closer in distance, your IOL can move to let you see it much better than you would with a monofocal lens. They do not have all the features of a multifocal lens, but they can result in better vision than you would get if you used only a monofocal lens.
  • Aspheric IOLs: Similar to accommodating IOLs, these are a great fit for people whose natural lens is an unusual shape. They are great for people with large pupils. In some people, aspheric lenses may make it difficult to see at night or in other low-light conditions.
  • Light Adjustable Lens: These adjustable IOLs from RxSight allow you to optimize your vision following cataract surgery. Through a series of light treatment procedures, your eye doctor can customize your vision to your lifestyle needs.

Keep in mind that if you require cataract surgery for both eyes, you may receive a different type of lens for each eye. Your surgeon will examine your eyes and see if they will need a different lens.

Before surgery, your doctor will ask you to list the medications you take, and they may advise against taking some of these prior to the procedure. Some people will have to use eye drops before their procedure.

Considerations for Young Children

Boy being fitted for glasses

The Food and Drug Administration has only approved IOLs for adults who are 18 and older. There are some circumstances during which a pediatric ophthalmologist may consider an IOL for a child or infant.

When an IOL is used for someone under the age of 18, it is considered off-label use. Infants and children who have cataract surgery may get an IOL implant as soon as their natural lens is removed, or they may use contacts and glasses to help with their vision for several years.

An IOL may still be an option when they get older and can make an informed decision. Children who do get cataract surgery receive general anesthesia. They only get the implant if their eye doctor believes the IOL will provide benefits that outweigh any possible risks.


The goal of cataract surgery is to help you see clearly. Your doctor will provide you with specific instructions for what to do during recovery, but they generally involve the following:

  • Use eye drops.
  • Avoid getting water, soap, or other irritants in the eye.
  • Avoid pressing or rubbing the eye. Some patients are instructed to wear a protective shield or eyeglasses.
  • Wear a protective shield over your eye during sleep.
  • Avoid exercise, driving, and other physical exertion until your doctor clears you for this type of activity.

Your doctor will also notify you of any possible complications or risks, such as:

  • Movement of the IOL.
  • Bleeding in the eye.
  • Eye infection.
  • Detached retina.
  • Loss of vision.
  • Pain that over-the-counter medication does not treat.

Frequently Asked Questions

When are intraocular lenses (IOLs) an option?

People with cataracts may have surgery that necessitates an IOL implant. Doctors will go over the patient’s health history and examine the eye. An IOL will be placed after a patient’s natural lens is removed.

What types of IOLs are there?

IOLs are all made of plastic, silicone, or acrylic. Like eyeglasses and contacts, they are available in a variety of focusing strengths: monofocals, aspheric (for irregularly shaped lenses), multifocal, accommodating, and toric.

How do IOLs work?

IOLs replace the clear lens in your eye and allow light to get in after your natural lens is removed due to cataract surgery. They allow you to better focus on what you see.

What are the risks of getting an IOL implant?

An IOL implant is a surgical procedure. It presents few or no major complications, but there are always risks involved, as with any surgery.

Patients must follow directions from their doctor, and use any eye drops or medications as instructed. Keep in mind that you may still need glasses or contacts after your IOL implant procedure.

Loss of vision, detached retina, pain that cannot be treated with over-the-counter options, eye infection, bleeding, and IOLs that move out of their location are all potential risks. IOLs are only recommended to patients who are good candidates for the procedure.


  1. Considering Cataract Surgery? What You Should Know. (September 2016). Harvard Health Publishing.
  2. Ocular Implants. (2019). The College of Optometrists.
  3. What Are the Different Types of Intraocular Implants and How Do I Decide on Which One to Get? (August 2009). ABC News.
  4. IOL Implants: Lens Replacements After Cataracts. (October 2019). American Academy of Ophthalmology.
  5. Cataract Surgery. (October 2019). American Academy of Ophthalmology.
  6. Multifocal Intraocular Lenses: Types, Outcomes, Complications, and How to Solve Them. (Oct–Dec 2017). Taiwan Journal of Ophthalmology.
  7. Cataract. MedlinePlus.
  8. Intraocular Lens Implant (IOL). (July 2017). American Association for Pediatric Ophthalmology and Strabismus.

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