All About Cataracts

People who have cataract surgery before age 65 appear to have a greater risk of clouding of the eye tissue directly behind the intraocular lens (IOL) that can lead to vision loss, according to a Swedish study.

The good news is that vision loss from this cataract surgery complication — called a posterior capsule opacity (PCO) — usually can be restored with a simple laser procedure called a ND:YAG laser capsulotomy.

Researchers at Norrlands University Hospital in Umea, Sweden, compared the vision of 116 patients who had cataract surgery prior to age 65 with the post-operative vision of patients age 65 and older at the time of surgery. Ten years after cataract surgery, 102 of the 116 people in the study group were given an eye exam and were asked to complete a questionnaire about their vision.

Analysis of the data revealed that within 10 years of cataract surgery, 37 percent of those younger than age 65 at the time of surgery experienced PCO and underwent a ND:YAG laser capsulotomy to restore their vision. In comparison, only 20 percent of those who were 65 or older at the time of cataract surgery required the laser procedure afterward.

The researchers concluded that more than one-third of patients in this study who were under age 65 at the time of cataract surgery subsequently developed a posterior capsule opacity that required a laser capsulotomy to restore vision.

Secondarily, the researchers said that 10 years after surgery, subjective visual function (measured with a questionnaire) and objective visual acuity (measured with an eye chart) remained stable in most patients who had cataract surgery when they are younger than age 65.

SOURCE: Ten-year longitudinal vision function and ND:YAG laser capsulotomy rates in patients less than 65 years at cataract surgery. American Journal of Ophthalmology. Published online November 18, 2009.

Results of a new study show that implantation of a light-filtering intraocular lens (IOL) during cataract surgery increases the amount of important nutrients in the eye and may reduce the risk of age-related macular degeneration.

The special IOL blocks high energy visible light (also called HEV light or blue light) that has been associated with damage to the retina. This damage occurs in the most sensitive part of the retina called the macula, which is responsible for central vision and color vision.

Prolonged exposure to blue light depletes macular pigments that protect important visual cells in the retina called photoreceptors. The blue light-filtering IOL helps preserve or increase these pigments, thereby reducing the risk of macular degeneration, according to the researchers.

Macular pigments include lutein and zeaxanthin.

In the study, 42 patients scheduled for cataract surgery were randomly assigned to have either the blue light-filtering acrylic IOL or a standard acrylic IOL implanted during their procedure.

Macular pigment optical density and blood serum levels of lutein and zeaxanthin were measured prior to surgery and at one week and three, six and 12 months after surgery.

The researchers found that there was an increase in protective macular pigments over time (as measured by optical density) in eyes with the light-filtering IOL implant, but no such increase in eyes with the standard IOL.

They concluded that this suggests the light-filtering IOL may reduce the risk of macular degeneration after cataract surgery, but they cautioned that further and long-term study is needed to determine if this is true.

Macular pigments are obtained entirely from the diet and are transported to the retina through the blood. Because of growing evidence that macular pigments play a role in reducing the risk or progression of macular degeneration, many commercially-available eye vitamins contain lutein and zeaxanthin.

A full report of the study appears in the October issue of Investigative Ophthalmology & Visual Science, the journal of The Association for Research in Vision and Ophthalmology (ARVO).