What are multifocal lenses?

After removal of a cataract during cataract surgery, an intraocular lens implant needs to be placed in the human eye to rehabilitate any visual impairment. A multifocal lens is an excellent option for vision correction at multiple points of focus: close-up for reading, intermediate range for computer work, and far-away for television and driving.

What are multifocal lenses and how do they work?

A multifocal lens is a type of intraocular lens implanted in the eye at the time of cataract surgery to provide visual perception at multiple ranges of distance. This type of lens would allow for excellent visual acuity after cataract surgery without the use of bifocals, progressive lens, or an eyeglass prescription. The lens implant has a concentric ring design to bend and split light rays entering the eye from multiple distances. These light rays can then be processed by the retina to deliver near vision, intermediate vision, and distant vision.

What types of multifocal lenses are there?

There are a variety of lenses that fall in the category of multifocal lenses, and each has its own distinctive benefits. These varieties include trifocal lenses that split light rays into different “channels” to maximize your freedom from eyeglasses and contact lens. Another variety of lens that falls in this category is an extended-depth-of-focus (EDOF) lens which functions by bending light rays rather than splitting them. These lenses offer excellent distance and intermediate vision to improve your vision and reduce your dependence on a pair of glasses. All of the varieties of multifocal lenses also offer astigmatism correction as well to maximize your experience of clear vision. Your eye care professional will be able to customize the corrective lens that is placed in your eye based on your lifestyle and vision demands.

How do you know if you need a multifocal lens?

If you are suffering from blurry vision due to cataracts, presbyopia (the need for reading glasses that arises in the mid forties), astigmatism, farsightedness, or nearsightedness, then a cataract procedure with the implantation of a multifocal lens may be the best way to solve your vision problems. An eye care professional specializing in ophthalmology or optometry would be able to perform an exam and give you more information about your candidacy for a multifocal lens. If you are already using multifocal contact lens, progressive lenses, or contact lenses to help you perform your daily activities, then a multifocal lens implantation may be a great option to reap the benefits of vision correction without the use of spectacles or contacts.

If you don’t have cataracts, but still need to use these vision devices to perform your daily activities, then a multifocal lens may give you visual freedom and prevent the future development of cataracts. Patients who fit this criteria usually benefit from a procedure known as refractive lens exchange. An eye examination from your eye care provider

FAQ’s About Multifocal Lenses

What are the benefits of multifocal lenses?

Multifocal lenses can correct refractive errors such as nearsightedness, farsightedness, and astigmatism. But more importantly, they can directly reverse the negative consequences of presbyopia. This is a an age-related change in the flexibility of the eye’s natural lens beginning in the mid-forties which makes it harder to see things at arm’s length. Presbyopia makes it necessary for these people to wear progressive eyeglass lenses so that they can read things at a near distance. One of the chief benefits of multifocal lenses is that they allow otherwise presbyopic patients the ability to function at all distances without the need for corrective lenses.

How do multifocal lenses differ from bifocal lenses?

Multifocal lenses provide functional vision for up-close activities (reading a book), intermediate-distance activities (reading a computer screen on a desktop), and far-distance activities (such as driving). On the other hand, bifocal lenses only provide functional vision for up-close activities, and far-distance activities. Bifocal lenses are often worn by people who are suffering from worsening close-up vision. More importantly, bifocal lenses require head positioning so that distance objects can be seen straight ahead through the upper part of a pair of glasses, while up-close objects can only be seen when looking through the lower portion of the corrective lens. Bifocal lenses will typically have a line on the lens that marks the boundary between near vision correction and distance vision correction.

Unlike bifocal lenses, a person who has multifocal lens implants does not need to adjust their head position based on the activity that they are performing. A multifocal lens can give you vision information from varying distances at the same time. Your brain quickly does the job of learning how to seamlessly integrate the gradual transitions from near, intermediate, and distance vision. Furthermore, when your friends or family look at your eyes, they will not be able to see any visible lines on the artificial lens.

Can multifocal lenses be used for both reading and distance vision?

Multifocal lenses can indeed correct vision at reading and distance vision. Though it is only one lens, it has a unique design consisting of concentric circles that allows for excellent visual acuity at different distances at the same time.

Are there any side effects or disadvantages of using multifocal lenses?

In rare instances, multifocal lenses may cause the sensation of haloes around lights in dimly lit conditions. For instance, you may notice a faint halo around a stoplight when driving at night. Nonetheless, this perception of halo tends to improve over the course of the first 6 months as your eyes adapt to the lens technology. The risks of developing this type of night time symptom is dependent on many different factors including the pupil size, the health of the cornea, and the type of multifocal lens chosen by the eye doctor.

An alternative to the multifocal lenses are the single vision lenses, also called monofocals. This variety of intraocular lens implant (a.k.a. IOL) is generally not associated with the sensation of floaters in dimly lit conditions, but seeing up-close objects would require the use of eyewear (i.e. cheaters or readers).

How long does it take to adjust to multifocal lenses?

Patients who receive multifocal lens implants usually notice an improvement in their vision within the 24 hours. The vision system may take 6 to 12 months to fully adjust to this new lens technology. By that time, most patients are seeing well at all distances, though they may keep one pair of readers around to read fine print.

Are multifocal lenses suitable for everyone?

Multifocal lenses tend to serve a better purpose in patients who have an active lifestyle and wish to have visual freedom. Patients who suffer from the age-related loss of flexibility of the natural lens that occurs in the mid-forties (i.e. presbyopes) will be delighted with the ability to read things on their phone without the need for reading glasses. Patients who are seeking a multifocal lens implant must be phakic, which means that they must have their natural lens intact. In other words, if cataract surgery has already been done in the past, then you may no longer be a candidate. An eye examination from your eye care provider will be important to determine if you are a good candidate for a multifocal lens implant.

If you have a history of other ophthalmic diseases such as strabismus, glaucoma, macular degeneration, or severe dry eye, then a multifocal lens implant may not be a good option for you. If you wear rigid gas permeable lens or if you wear soft contact lenses, you may need to suspend usage of these lenses for a couple of weeks prior to your evaluation in our office to maximize the reliability of our diagnostic imaging.

What are the costs associated with multifocal lenses compared to single-vision lenses?

If you are undergoing cataract surgery, a multifocal lens is usually not covered by Medicare nor any other private insurances. Insurance companies will usually only cover a single vision lens (a.k.a. monofocal lens). As such there is usually an out-of-pocket cost associated with a lens “upgrade.” The cost of this lens upgrade will also usually include all of the surgical planning that goes into using a multifocal lens implant. For instance, centration of this lens and correction of astigmatism are critical to the long-term success of the lens implant. In-office diagnostic testing, and a surgeon who has plenty of experience with these types of lenses is paramount to achieving excellent outcomes. So you are not only paying for the actual lens material, but also for the surgeon’s expertise. The cost for this type of lens implant varies depending on the surgeon and the region of the country.

source https://lucentvision2020.com/cataract-surgery/what-are-multifocal-lenses/