A cataract is a common age-related condition that causes clouding of the eye’s natural lens. This lens, made of clear protein and water, bends light rays that enter the eye and focuses them on the retina, allowing individuals see.1,2 When the lens proteins start to change and the lens itself starts to cloud, it can impede vision. An operation to remove the lens is warranted. A cataract cannot be removed with a laser or eye drops.3
There are different stages of cataract development, and over time it can lead to hazy, blurry, and less colorful vision.1 Fortunately, cataract surgery is a highly effective treatment that helps individuals regain clear vision through the use of modern technology to first remove the natural lens and then implant an artificial lens, which is called an intraocular lens, or IOL. The information provided here describes what cataract surgery is, explains the role of IOLs in improving visual function, and explores how these lenses are implanted and secured in the eye.
WHAT IS CATARACT SURGERY?
Cataract surgery is the most common surgical procedure performed worldwide. It can be performed at a hospital or outpatient clinic.2 Most patients experience improved vision shortly after surgery. The aim of surgery is to remove the clouded lens through a very small incision and replace it with an artificial IOL, inserted through the same incision.
One of the first steps of surgery is to remove the central anterior part of the lens capsule from the eye.4 In order to remove the cataract, the capsular bag, a thin, transparent membrane that surrounds the natural lens, must be opened. The surgeon then inserts a special instrument through a small incision in the cornea and uses it to break up and remove the cloudy lens. This process, known as phacoemulsification, uses ultrasound energy to emulsify the cataract and suction it out of the eye. Once the natural lens is removed, the surgeon replaces it with an IOL. Cataract surgery is typically performed as an outpatient procedure. Patients can usually go home in less than an hour, but they need someone else to drive them home.2 It can take about 8 to 12 weeks for the eye to completely heal.
WHAT IS AN INTRAOCULAR LENS?
An IOL is an artificial lens that is designed to restore clear vision after cataract removal. It is about one-third of the size of a dime.2 These lenses are made from hydrophobic or hydrophilic acrylic material or silicone, which are all biocompatible with the eye. A special coating is applied to an IOL to help protect the eye from the sun’s UV rays. Like prescription glasses or contact lenses, IOLs are designed with different focusing powers. The power of the lens is chosen based on the length of the eye and the curvature of the cornea.1
A variety of IOL designs are manufactured to address different visual needs. The type of IOL that is right for an individual depends on various factors, including their visual needs, lifestyle, and any preexisting eye conditions. Each IOL has unique features. Some lenses are designed to provide clear vision at a single focal point, usually for distance. These are called monofocal lenses. Individuals who have monofocal lenses may still require glasses for near tasks, such as reading.
Alternatively, some IOLs are designed to provide clear vision at multiple focal points. These are called multifocal IOLs. These lenses can reduce the need for glasses, but some individuals may still require them for specific activities. Another category of IOLs is a toric lens. Toric IOLs, designed to correct astigmatism, are available in monofocal and multifocal models. The latter design combines multiple features to address both astigmatism and age-related near vision loss, otherwise known as presbyopia.
The placement of an IOL is an important step in cataract surgery. After the surgeon removes the cataract with phacoemulsification, they carefully insert the IOL into the eye through a small incision and position it precisely in the capsular bag. The arms, or haptics, of the IOL expand into the periphery of the capsule to center and stabilize the lens.5 With the IOL positioned in the capsular bag, it naturally adheres to the remnants of the capsular bag as the capsule shrinks after surgery, which seals it into place and helps keep it in position. An IOL in a stable position will provide long-term clear vision.
In some cases, additional fixation of the IOL may be required to enhance its stability. In these situations, the surgeon can place sutures to hold the lens in position or select an IOL with a special haptic design to aid in fixation and prevent it from moving.
The natural healing process of the eye also contributes to the stability of the IOL. The surrounding tissues and capsule provide support and help keep the IOL securely in place.
The availability of IOLs has transformed the treatment of cataracts. When combined with phacoemulsification to remove the clouded natural lens, artificial IOLs allow individuals to regain clear vision and improve their quality of life. Carefully placed within the eye’s capsular bag during a routine surgical procedure, IOLs offer a tailored solution to address an individual’s visual needs.
Selecting an appropriate IOL for individual patients helps them experience improved vision at various distances and reduces their dependence on glasses. The stability of the IOL is achieved by its placement within the capsular bag and the natural healing process of the eye.
As technology advances, the development of innovative IOLs continues to enhance the outcomes of cataract surgery. With the help of skilled cataract surgeons and the use of high-quality artificial lenses, individuals can look forward to a brighter and clearer future.
- Boyd K. IOL implants: lens replacement after cataracts. American Academy of Ophthalmology. November 23, 2022. Accessed July 13, 2023. https://www.aao.org/eye-health/diseases/cataracts-iol-implants
- Smith M. What is an intraocular lens implant? WebMD. August 21. 2022. Accessed July 13, 2023. https://www.webmd.com/eye-health/cataracts/intraocular-lens-implant
- Cataract extraction and intraocular lens implantation. UCLA Health. Accessed July 13, 2023. https://www.uclahealth.org/medical-services/ophthalmology/surgical-treatments/cataract-extraction-and-intraocular-lens-implantation
- Wikipedia. Accessed July 13, 2023. https://en.wikipedia.org/wiki/Capsulorhexis
- Woodhams JT. What actually happens to an IOL in the first few hours and days after cataract surgery? Do they bounce around beore settling in the ‘capsular bag’? Woodhams Eye. Accessed July 13, 2023. https://www.woodhamseye.com/blog/what-actually-happens-to-an-iol-in-the-first-few-hours-and-days-after-cataract-surgery-do