All About Cataracts

Bausch & Lomb (Rochester, N.Y.) recently announced the U.S. launch of its new Akreos MICS lens, a foldable intraocular lens (IOL) designed for implantation through a 1.8 mm incision during phacoemulsification cataract surgery.

The ability to insert the new acrylic lens through such a small incision offers several potential advantages, including faster healing and less surgically-induced astigmatism, according to the company.

The lens also features aspheric optics designed to reduce spherical aberration and produce excellent post-operative vision. (Spherical aberration is a common higher-order aberration that can degrade vision and cause glare and halos around lights.)

The new Akreos IOL represents a new level of micro-incision cataract surgery (MICS). With most other IOLs used in MICS, an incision of 2.2 mm to 2.75 mm is required.

Prior to phacoemulsification technology, incision sizes of 10 mm or greater were common in cataract surgery, with greater risks of eye infection, delayed healing and other cataract surgery complications.

Because the Akreos MICS lens is a premium IOL, it may increase your cataract surgery cost if you choose this implantable lens for your surgery.

The Akreos MICS is the latest addition to Bausch & Lomb’s Akreos line of IOLs. First introduced in Europe over 10 years ago, more than 3 million Akreos IOLs have been implanted worldwide, according to the company.

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.

German company S&V Technologies has created custom-made intraocular lenses (IOLs) for animals with cataracts. The acrylic IOLs are implanted in the animals’ eyes during a procedure essentially the same as cataract surgery for humans.

Human cataract surgery is the most frequently performed surgery in the United States, and more than 90 percent of patients achieve good vision. For animals, cataracts usually mean blindness, according to Indgeborg Fromberg, head of the company’s veterinary division. Treating cataracts can improve the quality of life for animals, which have relatively short life spans, Fromberg says.

The company’s lenses have generated interest from around the world, including Sea World in San Diego for a sea lion that performs tricks, an Australian nature park for a blind kangaroo and a Romanian zoo for a visually impaired lioness. Additionally, the World Wildlife Fund has paid for cataract surgery with the lens implants for brown bears in a China nature reserve.

The company’s IOLs have also been used to restore vision for racehorses, circus animals, guide dogs and domestic pets.

Although the surgery is pricey, Fromberg says that many people consider their pets to be part of their family and are willing to pay the cost to restore the vision of their beloved furry friends.

Posterior capsule opacification (PCO) is one of the most common cataract surgery complications. It can occur relatively quickly after cataract surgery or months later.

The natural lens inside the eye is surrounded by a clear, membrane-like capsule. The front portion of this capsule is removed during cataract surgery to gain access to the cloudy natural lens and remove it. The posterior portion of the lens capsule is left intact to prevent loss of the gel-like fluid behind it, which would increase the risk of a detached retina from cataract surgery.

Posterior capsule opacification is thought to be caused by lens epithelial cells remaining in the eye after the cloudy lens is removed during cataract surgery. These cells can migrate onto the surface of the posterior capsule, where they undergo cellular changes and form an opaque membrane that decreases vision.

PCO can be successfully treated with a non-invasive outpatient procedure called a neodymium:YAG (Nd:YAG) laser capsulotomy. The procedure uses laser energy to obliterate the opacity, restoring vision.

Researchers at Storm Eye Institute, Medical University of South Carolina (Charleston, SC) recently conducted a retrospective study of 225 eyes that underwent cataract surgery with intraocular lens (IOL) implantation to investigate whether the type of IOL used in the surgery has an effect on the rate of PCO occurrence.

The eyes in the study received one of three IOLs: AcrySof ReSTOR SN60D3 (a spherical multifocal IOL), AcrySof Natural SN60AT (a spherical monofocal IOL), or AcrySof IQ SN60WF (an aspheric monofocal IOL).

All three IOLs are manufactured and marketed by the same company (Alcon, Inc.). Each lens was implanted in 75 study eyes, and mean follow-up time after surgery was 15.9 months.

The researchers found the rate of posterior capsule opacification after surgery was:

• 42.7 percent among eyes receiving the spherical multifocal IOL (ReSTOR)
• 28.0 percent among eyes receiving the spherical monofocal IOL (Natural)
• 14.7 percent among eyes receiving the aspheric monofocal IOL (IQ)

The Nd:YAG laser capsulotomy rate for eyes receiving the IOLs was 25.3 percent, 17.3 percent and 4.0 percent, respectively.

The researchers concluded that IOL design affects the rate of posterior capsule opacification occurring after cataract surgery.

Also, based on the rates of laser capsulotomy procedures performed, PCO appears to be less visually significant in eyes receiving the AcrySof IQ aspheric monofocal IOL, compared with eyes receiving the spherical multifocal IOL (AcrySof ReSTOR) and the spherical monofocal IOL (AcrySof Natural). 

The study was supported in part by Research to Prevent Blindness and the National Institutes of Health.

Source: Comparison of the incidence and visual significance of posterior capsule opacification between multifocal spherical, monofocal spherical, and monofocal aspheric intraocular lenses. Journal of Cataract & Refractive Surgery. July 2009.