Cataract surgery is the most common surgical procedure performed worldwide.1,2 Each year, an estimated 3.7 million, 7 million, and 20 million cataract surgeries are performed in the United States, Europe, and worldwide, respectively. Cataract surgery is also one of the safest surgeries, boasting a low complication rate.3
The standard of care for cataract surgery involves removing a cloudy lens from the eye using a process called phacoemulsification and replacing it with a tiny artificial lens called an intraocular lens (IOL).3 IOLs are essential to restore vision after cataract surgery and improve patients’ quality of life. Different types of IOLs are available today. Each has a unique design, benefits, and safety considerations that should be considered when selecting the IOL that is right for you. Your cataract surgeon can help you decide what IOL is right choice for your individual needs. During the preoperative examination and consultation, they will discuss the different types of IOLs (see IOL TYPES below), answer any IOL-related questions, and counsel you on the risks associated with surgery, such as infection, inflammation, increased intraocular pressure, retinal detachment, and glare or halos around lights. This conversation can help guide you to make the best decision.
IOL TYPES
Monofocal IOL. As the most common type of IOL, monofocal lenses have a fixed focus that is set for either distance or near vision.4 Most people target the monofocal lens for clear distance vision. Patients who choose monofocal lenses therefore often require reading glasses or contact lenses for activities that demand clear vision at near and intermediate distances.
Multifocal IOLs. Lenses with a multifocal design provide vision correction at multiple distances simultaneously.3 These IOLs are designed to reduce spectacle dependence for both near and distance vision. They have different zones with varying refractive powers, allowing patients to focus on objects at different distances simultaneously.4
Extended depth of focus IOLs. Lenses in this category provide benefits that are similar to those of multifocal IOLs, but instead of creating several foci they create one elongated focal point to enhance depth of focus.5 Extended depth of focus (EDOF) lenses are designed to provide sharp near and distance vision and reduce photic phenomena, glare, and halos—symptoms that can be associated with multifocal IOLs. Oftentimes, less effort is needed to refocus between distances with EDOF IOLs.
Toric IOLs. Toric lenses are designed to correct astigmatism, which is a common type of natural blur or misfocus that is caused by an irregular shape of the cornea. Astigmatism occurs when the eye is oblong, like the back of a spoon, rather than perfectly round. About one-third of eyes have astigmatism.7 Toric lenses have different powers in different meridians, providing enhanced clarity for patients with astigmatism.8 They are available in a variety of models, including monofocal, extended depth of focus, and multifocal designs.
SIMILARITIES AND DIFFERENCES IN LENS DESIGN
IOLs are surgically implanted in the eye during cataract surgery and are considered a permanent solution for vision correction. Even though they vary in design and function, all IOLs share a common goal of restoring clear vision. They are typically made from biocompatible materials such as silicone or acrylic to ensure long-term safety and compatibility with the eye.9
The main differences in IOL designs are the functionality and focusing abilities. Monofocal lenses offer a single fixed focus, whereas multifocal lenses provide a wider range of vision. Most individuals require spectacle or contact lens correction with monofocal IOLs whereas those who elect multifocal IOLs tend to have reduced dependence on correction for various distances. EDOF IOLs are another design that can reduce spectacle dependence. These lenses create one elongated focal point to enhance depth of focus. Lastly, accommodating IOLs can also reduce spectacle dependence and provide a dynamic range of vision.
CHOOSING AN IOL
IOL selection is based on multiple things. The first is eye health, including the presence of astigmatism, corneal issues, and other eye conditions. The second is lifestyle. During the preoperative consultation, your cataract surgeon will ask questions about your daily activities, hobbies, and visual requirements to help them determine what type of IOL will work best for you and increase the chance for you enjoy spectacle independence for certain if not all tasks. They should also ask about the intensity and frequency of your favorite activities and your vision expectations after surgery. Be open and honest with your ophthalmologist regarding your visual requirements and hobbies to ensure the selection of the most appropriate IOL.
Near vision activities. Tell your doctor if you like near vision activities such as reading, knitting, and detailed handwork. If so, a multifocal IOL may be a good choice for you assuming you are a candidate for the technology.
Distance vision activities. If you like distance vision activities like driving and sports, a monofocal IOL may be a suitable choice if you don’t mind wearing glasses or contact lenses for near tasks.
Hobbies and special interests. Certain hobbies and activities require specialized vision. Those who enjoy visually demanding activities such as photography and painting may benefit from enhanced contrast sensitivity and color perception. A variety of IOLs can help you achieve this goal.
Outdoor activities. Individuals who enjoy golfing, hiking, birdwatching, and other outdoor activities often prefer IOLs that minimize glare and enhance visual clarity in bright and challenging lighting conditions. Some IOLs are available with a tinted or polarization to enhance visual comfort and reduce glare.
The third consideration is cost. Different types of IOLs have varying costs. Insurance typically covers a standard monofocal IOL. It is important to consider your budget and discuss the financial aspect with your health care provider.
CONCLUSION
IOLs have revolutionized cataract surgery by providing patients with improved vision and reducing their dependence on glasses. The best IOL for you depends on various factors, including your lifestyle, visual goals, and eye health. Monofocal lenses are commonly used, but they only provide clear vision at one fixed distance. Alternatively, multifocal, accommodating, and toric lenses offer additional benefits for specific visual needs. Patients should have a detailed discussion with their ophthalmologist to select the most appropriate IOL that meets their individual requirements.
- Kauh CY, Blachley TS, Lichter PR, et al. Geographic variation in the rate and timing of cataract surgery among US communities. JAMA Ophthalmol.2016;134:267–276.
- Gower EW, Lindsley K, Tulenko SE, et al. Perioperative antibiotics for prevention of acute endophthalmitis after cataract surgery. Cochrane Database Syst Rev.2017;2:CD006364.
- Ho JW, Afshari NA. The quest to optimizing cataract surgery outcomes. Curr Opin Ophthalmol.2015;26:1–2.
- Boyd K. IOL implants: lens replacement after cataracts. American Academy of Ophthalmology. November 23, 2022. Accessed July 24, 2023. https://www.aao.org/eye-health/diseases/cataracts-iol-implants
- In light of understanding a new player in cataract surgery—extended depth of field lenses. April 1, 2022. Accessed July 24, 2023. https://cataractpatients.com/in-light-of-understanding-a-new-player-in-cataract-surgery—extended-depth-of-field-lenses
- Kelley S. Accommodating intraocular lenses (IOL) for cataract surgery. All About Vision. Accessed July 24, 2023. https://cataractpatients.com/in-light-of-understanding-a-new-player-in-cataract-surgery—extended-depth-of-field-lenses
- Common types and categories of astigmatism. September 5, 2022. Accessed July 24, 2023. https://www.oxfordfamilyvisioncare.com/blog/common-types-and-categories-of-astigmatism/#:~:text=Astigmatism%20is%20one%20of%20the,That’s%20over%20one%2Dthird!
- Chang DF. About the toric single focus lens implant. Accessed July 24, 2023. https://cataractpatients.com/in-light-of-understanding-a-new-player-in-cataract-surgery—extended-depth-of-field-lenses
- Smith M. What is an intraocular lens implant? WebMD. August 21. 2022. Accessed July 24, 2023. https://www.webmd.com/eye-health/cataracts/intraocular-lens-implant
