Intraocular Lens (IOL) Implants: Lens Replacement After Cataracts

What are IOLs?

Intraocular lenses (IOLs) are plastic lenses surgically inserted into the eyes of someone, usually because the person elected to have cataract surgery to regain clearer vision.

When you have this procedure, a surgeon removes the natural lens in your eye and replaces it with a permanent plastic IOL. Some IOLs can correct refractive errors.

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What are IOLs Used For? 

IOL implants accompany cataract removal surgery. A cataract is when the lens of the eye is cloudy.

If you have this condition, you may experience blurry or hazy vision. Because cataract surgery removes your natural eye lens, you’ll need an artificial replacement to restore your vision.

An eye surgeon (ophthalmologist) can insert a clear IOL in your eye in place of the clouded natural lens. The replacement helps to eliminate the foggy vision.

Some types of IOL can treat refractive errors, such as presbyopia, after cataract surgery. In these cases, an artificial lens is implanted in the eye to restore the ability to focus on nearby things.

IOL implants may be an option if you prefer not wear near-vision glasses following cataract removal.   

IOLs can also treat astigmatism (poor vision for both near and distant objects).

What Are IOLs Made Of?

Intraocular lens materials have evolved over time, from the original rigid plastics to today’s flexible silicone or acrylic construction. When selecting IOLs for cataract surgery, your surgeon will consider materials with proper attributes for optimal eye safety and health.

A primary issue with rigid IOLs for cataract surgery is that they require a larger corneal incision. In contrast, foldable IOLs can be inserted through a significantly smaller incision. The longer incision can take longer to heal and can be more susceptible to infection.

Hydrophobic acrylic and silicone IOLs are some of the most common artificial lenses for this surgery. Not only are they foldable, but they also have low water content (1 to 4 percent).

Similarly, modern IOLs have a clear, ultraviolet film that helps protect the eyes from sun damage.

Types of IOLs

Your vision correction requirements after cataract surgery will determine the right type of IOL for your eye. Primary considerations include:

• Type of refractive error (such as nearsightedness)
• Presence of multiple refractive errors (such as nearsightedness and farsightedness)

The common types of IOL are:

• Monofocal IOLs
• Multifocal IOLs
• Accommodative IOLs
• Toric IOLs

Monofocal IOLs

A monofocal lens corrects only one refractive error. It’s ideal for you if you have a near, medium-range, or distance vision problem.

Assume you have farsightedness and presbyopia (inability to focus on nearby objects) after cataract removal. You get a monofocal IOL for better distance vision, and then correct farsightedness with reading glasses.

Multifocal IOLs

A multifocal IOL can correct multiple focusing problems at the same time. You may get the implant to improve both distance and near vision.

If you wish to avoid wearing prescription glasses for career or other reasons, multifocal IOLs are an excellent option.

Accommodative IOLs

Like a multifocal lens, an accommodating IOL has multiple focusing powers. Accommodation means that the refractive power of the IOL implant adjusts as images come into focus in the eye.

Accommodating IOLs vary the eye’s focusing power in different ways, such as by folding or changing shape. The versatility enables your eye to see clearly at different distances, reducing your dependence on spectacles.

There are different types of accommodative IOLs, including:

• Single-optic IOLs: lenses move inside the eye
• Duo-optics IOLs: lenses change their position inside the eye
• Deforming IOLs: Lenses change shapes

Toric IOLs

When your cornea or lens has an irregular curvature, you may develop distance and near-vision difficulty at the same time. Toric IOL implantation can correct this error.   

What is Refractive Lens Exchange (RLE)?

Refractive lens exchange is the surgical removal and replacement of the natural eye lens with an artificial one to correct a refractive error.

Your ophthalmologist may recommend RLE if you have severe myopia, astigmatism or farsightedness. In that case, you may not be a good candidate for surgical reshaping of the cornea to correct your refractive error.

The doctor will extract your clear lens out of the eye during the RLE procedure. This may be necessary even if you don’t have a cataract in your eye.

After lens removal, you’ll get a biocompatible artificial replacement that repairs your vision. 

How Do IOLs Work?

Every IOL is different for each person because everybody receives an intraocular lens implant that matches their refractive error. The IOL serves the same function as a natural lens.

When light enters the eye, the IOL focuses it on the retina.  It can correct nearsightedness or farsightedness in the same way prescription contact lenses or glasses would.  

How Long Do IOLs They Last?

Unlike traditional contact lenses, artificial implants are meant to stay in the eye permanently. Reasons for IOL removal include an inserted lens failing to correct the patient’s refractive error. Having an ophthalmologist remove an IOL implant is rare.

See your ophthalmologist if you experience blurry vision after IOL implantation surgery. You may require an RLE that provides the correct refractive power.    

Are IOLs Safe?

IOL implants can restore vision acuity and clarity. But there are risks associated with cataract surgery and the inserted lenses.

Discuss with your ophthalmologists applicable RLE/IOL surgery risks, such as:

• Bleeding in the eye
• Eye infection and swelling
• Swelling and detachment of the retina at the back of the eye
• Blurry vision
• IOLs can move out of position
• Persistent pain
• General eye damage

Recovery Time After IOL Implant Procedure

It may take days or weeks to recover fully from your IOL implantation surgery. Your ophthalmologist will advise you on appropriate self-care measures to accelerate recovery and minimize the risk of postoperative complications.

FAQs

What are IOLs used for?

IOLs help the eye to focus images for better near, medium-range, or distance vision. People have these artificial lenses inserted in the eye after their natural lens has been removed during cataract surgery.

You may have IOL implantation surgery to correct a refractive error without the need to wear glasses.

What are the types of IOLs?

Types of intraocular lenses include monofocal, which can correct near, medium-range, or far vision. A multifocal IOL or accommodative IOL can improve both near and distance vision simultaneously.

Toric lenses are for patients with astigmatism (blurred near and distance vision due to changes in the shape of the cornea or lens).

References

1. IOL Implants: Lens Replacement After Cataracts. (April 2021). American Academy of Ophthalmology.

2. Surgical Options for Correction of Refractive Error Following Cataract Surgery. (October 2014). Eye and Vision.

3. Intraocular Lens (IOL) Materials. (November 2019).  Intechopen.

4. Accommodative Intraocular Lenses: Where are we and Where we are Going. (June 2017). Eye and Vision.

5. Review of Current Status of Refractive Lens Exchange and Role of Dysfunctional Lens Index as its New Indication. (2020). Indian Journal of Ophthalmology.

6. Is it Possible to Remove an Incorrect IOL?. (February 2014). American Academy of Ophthalmology.

7. Cataract Surgery: Risks, Recovery, Costs. (September 2021). American Academy of Ophthalmology.