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).

The use of premium intraocular lenses (IOLs) in cataract surgery performed in the United States is increasing, according to recent surveys.

Premium IOLs include multifocal lens implants and accommodating IOLs. Both types of presbyopia-correcting intraocular lenses give patients a broader range of vision, reducing or eliminating the need for reading glasses after cataract surgery.

According to a recent survey of cataract and refractive surgeons reported by the eyecare industry research firm Market Scope, 71 percent of U.S. eye surgeons offered their patients the option of premium IOLs in 2008, up from approximately 59 percent in 2007. The company also estimates that 210,000 presbyopia-correcting IOLs were implanted during cataract surgery or other vision correction procedures in the U.S. in 2008, up from 153,000 in 2007.

Eye surgeons also say they prefer premium IOLs for the correction of high myopia. In a 2008 member survey of the American Society of Cataract and Refractive Surgery (ASCRS) more eye surgeons responding to the survey reported preferring premium IOLs (40 percent) to LASIK (23 percent) for the correction of large amounts of nearsightedness in patients desiring elective refractive surgery.

Among ASCRS surgeons using presbyopia-correcting premium IOLs, their top three lens choices in 2008 were the AcrySof ReSTOR multifocal IOL (Alcon), the Crystalens accommodating IOL (Bausch & Lomb) and the ReZoom Multifocal IOL (Abbott Medical Optics).

Other premium intraocular lenses include toric IOLs that correct astigmatism and aspheric IOLs designed to reduce glare and improve night vision.

Premium IOLs cost more than standard IOLs, and the added expense of these lenses typically is not covered by vision insurance and must be paid out-of-pocket, increasing your cataract surgery cost. However, most people who choose premium IOLs are very pleased with the added visual benefits the lenses provide, according to eye surgeons who offer them.

The U.S. Food and Drug Administration (FDA) recently approved a new astigmatism-correcting intraocular lens (IOL) for use in cataract surgery. The new lens, called the AcrySof IQ Toric IOL, is manufactured by Alcon and is now available for use by cataract surgeons in the United States.

In addition to having a toric design to correct astigmatism, the new premium IOL also has aspheric curves to reduce a common post-surgical optical error called spherical aberration. By reducing spherical aberration, the AcrySof IQ Toric IOL is designed to improve image quality and contrast sensitivity for better night driving vision and sharper vision overall.

In a clinical trial required by the FDA prior to approval, among 37 patients who had the IOL implanted bilaterally for the treatment of cataracts and astigmatism, 98 percent did not need prescription eyeglasses for distance vision six months after surgery. Also, the lens continued to show good rotational stability when checked one year after surgery. 

According to Alcon, the AcrySof IQ Toric IOL is a good choice for any patient undergoing cataract surgery who has 0.75 diopter (D) or more corneal astigmatism prior to surgery. The IOL corrects up to 2.50 D of astigmatism, and it can be combined with a procedure called limbal relaxing incisions to correct even higher amounts of astigmatism.

Like other premium IOLs, the AcrySof IQ Toric IOL costs more than a conventional monofocal intraocular lens and will increase your cataract surgery cost. For details, consult a cataract surgeon near you.