All About Cataracts

Most cataracts are age-related eye problems and affect people age 50 and older. But cataracts also can be present at or near birth. In these instances, the lens opacities are called congenital cataracts.

Early treatment of congenital cataracts is essential for normal vision development and to prevent amblyopia or blindness.

Researchers in England recently investigated the current status of cataract surgery performed in the UK and Ireland for children age two years and younger.

Surveys were sent to 928 ophthalmologists, with a response rate of roughly 75 percent.

Findings of the study included:

• 47 of the respondents (7 percent) performed congenital cataract surgery on children age 2 and younger.
• Among those performing the surgery, 41 (87 percent) performed primary intraocular lens (IOL) implantation in these children.
• One quarter of respondents said they would not implant an IOL in a child under 1 year old. 

Other reasons surgeons provided for not performing primary IOL implantation included the presence of other eye conditions, including microphthalmos (70% of respondents), anterior eye problems (52 percent), posterior eye anomalies (61 percent), and glaucoma (19 percent).

Microphthalmos is a developmental anomaly characterized by one or both eyes being abnormally small.

The researchers concluded that surgery for congenital cataracts with IOL implantation in children age 2 years and younger has been widely adopted in the UK and Ireland by the relatively small number of ophthalmologists who manage these children.

Among these ophthalmologists, there is general agreement concerning surgical technique, choice of IOL design and the formula used for IOL power calculation. But variation exists in eligibility criteria for IOL implantation, and this may reflect a lack of consensus on which children are most likely to benefit from it and the risks involved.

The researchers also said there is a need for systematic studies of the outcomes of primary IOL implantation in younger children.

Source: Cataract surgery and primary intraocular lens implantation in children 2 years old in the United Kingdom and Ireland: findings of national surveys. British Journal of Ophthalmology. Published online June 16, 2009.

Having multifocal intraocular lenses (IOLs) implanted in both eyes for the treatment of cataracts produces better visual outcomes than a single multifocal IOL implanted in one eye, according to a study published in the June 2009 issue of Journal of Cataract & Refractive Surgery.

In the study, an AcrySof ReSTOR multifocal IOL was implanted 1) in one eye of patients with a natural (non-cataractous) lens in the other eye; 2) in one eye of patients who had a conventional monofocal IOL implanted in the other eye; and 3) in both eyes of patients with a cataract in one or both eyes.

Visual acuity, contrast sensitivity and stereopsis (depth perception) of all eyes was measured six months after cataract surgery. Patients also were surveyed about the quality of their vision and their overall satisfaction.

Patients receiving bilateral multifocal IOLs had the highest satisfaction score (92 percent), and 77 percent of these patients achieved spectacle independence after surgery.

Among patients with the multifocal IOL implanted in one eye only, 75 percent reported being satisfied with their vision, and spectacle independence was achieved by 56 percent of patients with a natural lens in their other eye and 65 percent of those who had a monofocal IOL implanted in their other eye.

Patients with bilateral multifocal IOLs also had better uncorrected near visual acuity, stereopsis, best-corrected near vision and best-corrected intermediate vision.

More patients with bilateral multifocal IOLs (77 percent) experienced halos at night compared with patients who received a multifocal IOL in one eye only (57 percent), but in most cases halos were minot and did not significantly affect patients’ overall satisfaction with their visual outcome.

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.

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.