All About Cataracts

Subjects undergoing cataract surgery with implantation of the AcrySof Natural IOL (Alcon Laboratories, Inc., Fort Worth, Tex.) achieved better contrast sensitivity under conditions of veiling glare than subjects receiving a clear IOL, according to a new study.

Researchers at the University of Georgia (Athens, GA) assessed the vision of a total of 58 subjects: 17 with yellow AcrySof Natural IOLs implanted after cataract surgery, 20 with clear IOLs implanted after cataract surgery and 21 control subjects who did not have cataracts.

The yellow-colored AcrySof Natural IOL filters ultraviolet (UV) and high-energy visible light (also called “blue light”), which has been associated with glare.

Two tests were performed:

1. Visual acuity under veiling glare conditions. Subjects watched a contrast sensitivity (CS) target while a circular xenon lamp was directed toward their eyes and the intensity of the light was adjusted until the target was no longer visible.
2. Photostress recovery. The time required to detect a CS target after a 5-second exposure to an intense circular disk of broad-band xenon light.

In the test of visual acuity under veiling glare, eyes with the AcrySof Natural IOL could withstand significantly more light than eyes with a clear intraocular lens and eyes with a natural lens (no cataracts).

In the photostress test, visual recovery was faster in eyes with natural lenses (no cataracts) than eyes with either type of IOL. Photostress recovery times in eyes with the two types of IOLs were similar.

The researchers concluded the blue-filtering AcrySof Natural IOL is associated with reduced glare disability compared with clear IOLs and control eyes without cataracts.

The AcrySof Natural IOL may be considered a premium intraocular lens and may increase your cataract surgery cost if you choose this lens implant.

The full report of the comparison test (”The effect of the AcrySof Natural lens on glare disability and photostress”) is published in the August 2009 issue of the American Journal of Ophthalmology.

Aspheric intraocular lenses (IOLs) used in cataract surgery provide higher quality vision than spherical IOLs, according to a new study.

Researchers at Johann Wolfgang Goethe-University (Frankfurt, Germany) and Cullen Eye Institute, Baylor College of Medicine (Houston) performed bilateral cataract surgery on 26 patients. The patients received an aspheric IOL in one eye and a spherical IOL in the other. All lenses were produced by the same manufacturer (Alcon).

Aspheric IOLs feature a gradually changing curve from the center of the lens outward and are designed to control spherical aberration produced by spherical IOLs. Spherical aberration is one of many higher-order aberrations of the eye, and is believed to cause glare and halos around lights at night.

Six months after surgery, aberrometry and visual acuity measurements showed the eyes receiving the aspheric IOLs had significantly lower spherical aberration, better visual acuity (measured with an eye chart in medium/low lighting) and better contrast sensitivity than the eyes with spherical lens implants.

The researchers concluded that aspheric IOLs produce better retinal image quality and higher quality vision than spherical IOLs.

Note: Aspheric IOLs typically are considered premium lens implants, and choosing this type of intraocular lens may increase the your cataract surgery cost.

Source: Effect of intraocular lens asphericity on quality of vision after cataract removal: An intraindividual comparison. Ophthalmology. Published online July 29, 2009.

Crystalens HD, the latest generation accommodating IOL produced by Bausch & Lomb, improves vision at all distances compared to the company’s previous model, the Crystalens Five-O, according to a new study.

Speaking at the recent annual meeting of the American Society of Cataract and Refractive Surgery, Jay S. Pepose, MD, PhD, presented the results of a study of 67 eyes implanted with the Crystalens HD intraocular lens during cataract surgery. At one month after surgery, monocular testing of uncorrected visual acuity (UCVA) revealed:

• 79 percent of the eyes were 20/30 or better for distance vision
• 97 percent of the eyes were 20/30 or better for intermediate vision (approximately 32 inches)
• 85 percent of the eyes were 20/30 or better for near vision (approximately 16 inches)

Best-corrected visual acuity (BCVA) with eyeglasses for distance vision was 20/20 or better in 96 percent of eyes and 20/30 or better in 100 percent.

Compared with data from cataract surgery using the earlier Crystalens accommodating IOL, the new Crystalens HD provides better vision at all distances. Forty-two percent of eyes receiving the Crystalens HD IOL attained uncorrected distance vision of 20/20 or better, which is 50 percent higher than the percentage of eyes attaining the same level of UCVA after surgery with the Crystalens Five-O, said Dr. Pepose.

The Crystalens HD also surpassed the UCVA performance of a leading brand of multifocal IOL (AcrySof ReSTOR, Alcon) for distance and intermediate vision:

• 57 percent of eyes with Crystalens HD were 20/25 or better at distance
• 45 percent of eyes with the multifocal IOL were 20/25 or better at distance
• 91 percent of eyes with the Crystalens HD were 20/25 or better at intermediate
• 35 percent of eyes with the multifocal IOL were 20/25 or better at intermediate

The AcrySof ReSTOR multifocal IOL, on the other hand, performed better than the Crystalens HD accommodating IOL when comparing uncorrected near vision. Twice as many eyes receiving the multifocal lens attained 20/20 or better UCVA at near than eyes receiving the Crystalens HD. But the percentage of eyes attaining 20/30 or better UCVA at near was roughly the same for both groups (85 percent).

Accommodating IOLs are single vision intraocular lenses that move slightly in the eye in response to focusing effort to provide a full range of vision. Multifocal IOLs maintain a fixed position within the eye but have an optical portion that contains several lens powers to provide a full range of vision. Both types of IOLs can decrease the need for reading glasses and computer glasses after cataract surgery.

Accommodating IOLs and multifocal IOLs are premium intraocular lenses that cost more than traditional monofocal IOLs used in cataract surgery. Therefore, choosing these lenses will increase your cataract surgery cost. For details, consult a cataract surgeon near you.

Disclosure:  Dr. Pepose, director of Pepose Vision Institute (Chesterfield, MO) and professor of clinical ophthalmology, School of Medicine, Washington University (St. Louis, MO), is a paid a consultant to Bausch & Lomb.

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.