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What do multifocal and accommodative IOLs do to clear vision?

Dr. Alan J. Margolis, MD
Ophthalmologist (Eye Specialist)

Prior to undergoing cataract surgery, your ophthalmologist will perform a variety of tests and examinations, the goal of which are to determine the shape and condition of your eye before surgery. The corneal shape, length of the eyeball, health of the macula, and the presence or absence of other ophthalmic diseases will help guide your ophthalmologist to recommend a specific lens implant for you.

Your goals with respect to visual function after cataract surgery are usually a significant part of this conversation. Some people choose to continue wearing glasses after cataract surgery, while others seek the maximum degree of spectacle freedom possible. Once your goals have been articulated and your ocular condition established, your ophthalmologist will team with you to choose the lens that best addresses your needs and interests. We are able to target distance, near and intermediate vision with our lens implants. Indeed, for some people, we are able to use lenses which improve function in all of these circumstances.

It is important to recognize that no lens implant is perfect and that our goal should try to be improvement in visual function rather than the attainment of perfection of vision. When the ophthalmologist and the patient are able to align their expectations, both parties are usually much happier with the outcomes.

The eye’s lens, which contributes to your focusing power, has four primary functions:

  • Transparency. To provide a clear medium through which light rays from an object can reach your retina.
  • Optical. To focus a sharp image of an object onto the retina.
  • Anatomic. To create a functional barrier between the front (anterior) and back (posterior) segments of the eye.
  • Accommodation. To vary the eye’s refractive power, providing clear images of objects over a wide range of near, far and intermediate distances.

For people with cataracts, the lens of the eye becomes cloudy. Light cannot pass through it easily, and their vision is blurred. Cataract surgery is used to remove the cloudy lens and replace it with a clear IOL.

In some cases, people without cataracts who want to reduce or eliminate their need for glasses and who may not be candidates for LASIK may choose to have an IOL implanted in a procedure called refractive lens exchange (RLE). This procedure may be used to correct moderate to high degrees of myopia (nearsightedness), hyperopia (farsightedness) and presbyopia (the inability to focus at near distances with age).

When the natural lens is removed during cataract surgery, or removed as a form of refractive surgery, IOLs are inserted to take the place of the natural lens. IOLs are artificial lenses surgically implanted in the eye, replacing the eye’s natural lens. These lenses help your eye to regain its focusing and refractive ability.

The most common type of implantable lens is the monofocal, or fixed-focus lens, which is intended to give clear vision at one distance. In order to see clearly at all ranges of distances, one is required to wear glasses or contact lenses.

Other types of lenses which are gaining in popularity are the multifocal and accommodative lenses. These IOLs may be used to treat myopia, hyperopia and presbyopia, and may allow less reliance on glasses, contact lenses, or both to see clearly at a distance and near.

A multifocal IOL has several rings of different powers built into the lens. The part of the lens (ring) you look through will determine if you see clearly at a far, near or intermediate distance (this is sometimes called pseudoaccommodation).

An accommodative IOL is hinged to work in coordination with the eye muscles. The design allows the accommodative lens to move forward as the eye focuses on near objects, and move backward as it focuses on distant objects.

Phakic intraocular lenses (IOLs) are designed for people with high degrees of refractive errors that cannot be safely corrected with corneal-based refractive surgery. The phakic IOL, sometimes referred to as an implantable contact lens or ICL, is surgically implanted inside the eye in front of the eye’s natural lens. The eye’s natural (phakic) lens is not removed, so patients can retain their pre-existing ability to focus.

During the phakic IOL procedure, your ophthalmologist places the phakic IOL either in front of or behind the iris of the eye. Once the IOL is properly positioned inside the eye, it provides the necessary correction to redirect light rays precisely onto the retina.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.