Before intra-ocular lenses (IOLs) were developed, people had to wear very thick eyeglasses or special contact lenses to be able to see after cataract surgery. Now, with cataract lens replacement, several types of IOL implants are available to help people enjoy improved vision. Discuss these options with your eye doctor to determine the IOL that best suits your vision needs and lifestyle.
Before surgery your eyes are measured to determine your IOL prescription, and you and your eye doctor will compare options to decide which IOL type is best for you, depending in part on how you feel about wearing glasses for reading and near vision.The type of IOL implanted will affect how you see when not wearing eyeglasses. Glasses may still be needed by some people for some activities.If you have astigmatism, your Eye M.D. will discuss toric IOLs and related treatment options with you.In certain cases, cost may be a deciding factor for you if you have the option of selecting special premium lOLs that may reduce your need for glasses.
This common IOL type has been used for several decades. Monofocals are set to provide best corrected vision at near, intermediate or far distances. Most people who choose monofocals have their IOLs set for distance vision and use reading glasses for near activities. On the other hand, a person whose IOLs were set to correct near vision would need glasses to see distant objects clearly.Some who choose monofocals decide to have the IOL for one eye set for distance vision, and the other set for near vision, a strategy called “monovision.” The brain adapts and synthesizes the information from both eyes to provide vision at intermediate distances. Often this reduces the need for reading glasses. People who regularly use computers, PDAs or other digital devices may find this especially useful. Individuals considering monovision may be able to try this technique with contact lenses first to see how well they can adapt to monovision. Those who require crisp, detailed vision may decide monovision is not for them. People with appropriate vision prescriptions may find that monovision allows them see well at most distances with little or no need for eyeglasses. Presbyopia is a condition that affects everyone at some point after age 40, when the eye’s lens becomes less flexible and makes near vision more difficult, especially in low light. Since presbyopia makes it difficult to see near objects clearly, even people without cataracts need reading glasses or an equivalent form of vision correction.
These newer IOL types reduce or eliminate the need for glasses or contact lenses. In the multifocal type, a series of focal zones or rings is designed into the IOL. Depending on where incoming light focuses through the zones, the person may be able to see both near and distant objects clearly. The design of the accommodative lens allows certain eye muscles to move the IOL forward and backward, changing the focus much as it would with a natural lens, allowing near and distance vision. The ability to read and perform other tasks without glasses varies from person to person but is generally best when multifocal or accommodative IOLs are placed in both eyes. It usually takes 6 to 12 weeks after surgery on the second eye for the brain to adapt and vision improvement to be complete with either of these IOL types.
For many people, these IOL types reduce but do not eliminate the need for glasses or contact lenses. For example, a person can read without glasses, but the words appear less clear than with glasses. Each person’s success with these IOLs may depend on the size of his/her pupils and other eye health factors. People with astigmatism can ask their eye doctor about toric IOLs and related treatments. Side effects such as glare or halos around lights, or decreased sharpness of vision (contrast sensitivity) may occur, especially at night or in dim light. Most people adapt to and are not bothered by these effects, but those who frequently drive at night or need to focus on close-up work may be more satisfied with monofocal IOLs.
The latest addition to the TECNIS® Family of IOLs offers new optical technology for providing an Extended Range of Vision.
Traditional IOL solutions for treating presbyopia include Multifocals and Trifocals, which work on the principle of simultaneous vision by splitting light into multiple distinct foci, and Accommodative IOLs, which change in shape and power when the ciliary muscle contracts.
Traditionally with these technologies, the correction of presbyopia is commonly thought of in terms of the distinct distance for which functional vision is provided.
Proprietary diffractive echelette design feature introduces a novel pattern of light diffraction that elongates the focus of the eye resulting in an extended range of vision.1
As evidenced by the measured light pattern when projected through the TECNIS® monofocal IOL, TECNIS® multifocal IOL and the TECNIS® Symfony extended range of vision IOL, there is one distinct focal point for distance with the TECNIS® monofocal lens, two distinct foci for the TECNIS® multifocal lens, and one elongated focal point for the TECNIS® Symfony extended range of vision IOL.
The novel pattern of light diffraction projected through the TECNIS® Symfony IOL is shown below, along with the light patterns projected through the TECNIS® monofocal and TECNIS® multifocal IOLs for comparison.
The elongated focus of the TECNIS® Symfony lens leads to:
|TECNIS® Monofocal IOL|
|TECNIS® Multifocal IOL|
|TECNIS® Symfony IOL|
TECNIS® IOL Showed:3
|Chromatic Aberration = 1.2 D4||Chromatic Aberration = 0.14 D5|
Achromat technology for the correction of longitudinal chromatic aberration (LCA) causes contrast enhancement.
Correction of corneal chromatic aberration results in a sharper focus of light. When combined with correction of spherical aberration, it increases retinal image quality, without negatively affecting depth of focus.5,7
|LCA = 1.20 Diopters4||LCA = 0.14 Diopters5|
Modulation transfer function (MTF) calculated for mesopic pupil sizes in clinically-validated eye models.5
White light MTF at 50 c/mm measured in the ACE model eye for a 5 mm pupil.8
High Spectacle Independence1
Halos Comparable to a Monofocal IOL1