All About Cataracts

Premium intraocular lenses designed to correct astigmatism — called toric IOLs — produce excellent visual outcomes and high patient satisfaction, according to a new study.

Researchers in Canada evaluated the implantation of toric IOLs in subjects undergoing cataract surgery in both eyes. The study included 234 eyes of 117 subjects. In addition to having cataracts, all subjects had from 1.00 to 2.50 diopters (D) of corneal astigmatism prior to surgery.

After cataract removal, all eyes were implanted with an AcrySof Toric IOL made by Alcon (Fort Worth, Texas).

Binocular uncorrected distance visual acuity (UDVA), refractive error, and IOL rotational stability were assessed at 1 day and 1, 3 and 6 months after surgery.

Prior to surgery and at 3 months and 6 months after surgery, patients completed a questionnaire that assessed their dependence on eyeglasses, visual disturbances and satisfaction with their vision using a 10-point scale (1 = completely unsatisfied; 10 = completely satisfied).

Results of the study included:

• Binocular UDVA after surgery was 20/40 or better in 99 percent of patients and 20/20 or better in 63 percent of patients.
• Mean residual refractive astigmatism after surgery was reduced to 0.4 D among all patients.
• IOL alignment was within 5 degrees of the intended position in 91 percent of patients and within 10 degrees of intended in 99 percent of patients.
• 69 percent of patients reported never needing glasses for distance vision after surgery.
• The frequency and severity of halos and glare present prior to surgery were significantly reduced after surgery.
• Satisfaction with vision was rated 7 or higher by 94 percent of patients after surgery.

The researchers concluded that cataract surgery with bilateral implantation of toric IOLs to correct pre-existing astigmatism produced “excellent and stable visual outcomes that patients rated as highly satisfactory.”

A full report of the study is published in the April 2010 issue of Journal of Cataract and Refractive Surgery, the official journal of the American Society of Cataract and Refractive Surgery (ASCRS) and the European Society of Cataract and Refractive Surgeons (ESCRS).

Advances in cataract surgery are occurring every year, making the procedure safer and more effective than ever.

A number of the key advances in cataract surgery took place in 2008. Among the new technology and techniques:

New Phacoemulsification Technology

Phacoemulsification (or “phaco”) is a cataract surgery technique in which the cataract is broken up into small pieces with a small, hand-held probe that has a vibrating tip. The small pieces are then removed from the eye with suction. Phaco is currently the most common technique used for cataract surgery in the United States.

Manufacturers of phaco equipment for cataract surgery introduced several advances in 2008, including probes that allow the procedure to be performed with smaller incisions. This reduces the risk of unwanted astigmatism after cataract surgery. Other advances include new microsurgical tools to help break up very dense cataracts more effectively during phaco cataract surgery.

New Lens Implants

New intraocular lenses (IOLs) introduced or in development in 2008 include presbyopia-correcting IOLs, aspheric IOLs and toric IOLs.

Presbyopia-correcting IOLs

These innovative lenses help restore a person’s ability to see well up close as well as far away, thereby reducing the need for reading glasses and computer glasses after cataract surgery.

The Crystalens HD (Bausch & Lomb) presbyopia-correcting lens that was introduced in 2008 works by having the ability to change position slightly within the eye in response to focusing effort. This type of presbyopia-correcting IOL is also called an “accommodating” IOL. Other brands of accommodating IOLs are currently in development.

Another type of presbyopia-correcting intraocular lens is the multifocal IOL. Multifocal IOLs are similar in design to multifocal contact lenses, containing separate lens powers for seeing distant, intermediate and near objects simultaneously. Examples of multifocal IOLs include The AcrySof ReSTOR IOL (Alcon Laboratories) and the ReZoom Multifocal Lens (Advanced Medical Optics).

Accommodating and multifocal IOLs can be implanted in both eyes, or in one eye only for a “monovision” effect. Some surgeons feel a monovision correction provides better distance vision than having presbyopia-correcting IOLs implanted in both eyes.

Aspheric IOLs

Aspheric IOLs are specially designed to more closely mimic the shape of the eye’s natural lens, which changes in curvature from its center to its periphery. This characteristic of possessing a gradually changing curve is called asphericity (meaning “not spherical,” or “not of the same curve”).

Because they are more similar in shape to the eye’s natural lens, aspheric IOLs are designed to provide sharper vision and reduce higher-order aberrations (HOAs) caused by traditional spherical IOLs. HOAs contribute to glare and reduced contrast sensitivity, especially at night and in other low-light conditions.

Many cataract surgeons appear to believe in the benefits of aspheric IOLs, as the use of thes premium IOLs grew rapidly in 2008.

Examples of aspheric IOLs include the Tecnis IOL (Advanced Medical Optics) and the AcrySof IQ IOL (Alcon Laboratories).

Toric IOLs

Toric IOLs are a new type of premium intraocular lenses that correct astigmatism.

In the past, people who had astigmatism and cataracts had to wear eyeglasses or have an additional surgical procedure to correct their astigmatism after cataract surgery. With toric IOLs, many of these people can see clearly after cataract surgery without the need for full-time glasses or additional surgery.

Use of toric IOLs increased significantly in 2008 and continued future growth is expected. Examples of toric IOLs include the AcrySof Toric IOL (Alcon Laboratories) and the STAAR Toric IOL (STAAR Surgical Co.)

More Advances on the Horizon

As the aging of the U.S. population continues, more and more Americans are having cataract surgery. And more advances in cataract surgery technology are occurring every year, including techniques for smaller incisions and faster recovery time.

To stay up-to-date on the latest news about cataracts and cataract surgery, return to AllAboutCataracts.com often. Or browse AllAboutVision.com’s Cataract Surgeon Directory to find a cataract surgeon near you.