Implanting blue light-filtering IOLs during cataract surgery may help preserve retina health

Implanting blue light-filtering intraocular lenses (IOLs) during cataract surgery helps maintain visual function and may preserve the health of the retina, specifically in disease states such as age-related macular degeneration (AMD), according to a comprehensive review published in the May/June 2010 edition of Survey of Ophthalmology. Prolonged exposure to short-wavelength blue light is harmful to the retina, leading to age-related diseases of the eye and vision loss.

"As a cataract surgeon, I am committed to helping my patients reduce their vision loss," said review author Bonnie Henderson, MD, Ophthalmic Consultants of Boston and Assistant Clinical Professor of Ophthalmology at Harvard Medical School. "Blue light-filtering IOLs are an important option I am able to offer my patients to help maximize their visual outcomes and also help potentially prevent damage to the retina."

With baby-boom demographics on the rise, age-related eye diseases – such as AMD – are expected to become major economic and social factors in health care. Methods to prevent age-related diseases with blue light-filtering IOLs may prove to have lasting, favorable effects on the health of the aging baby-boom generation.

Blue light-filtering lenses are designed to mimic the natural crystalline lens of a 53-year-old, and help reduce the amount of harmful blue light reaching the retina. The goal of this technology is to reduce vision loss and improve quality of life for the millions of older patients who need cataract surgery.

Several lines of research show exposure to short-wavelength blue light, a portion of the visible light spectrum, may be associated with an increased risk for retinal damage and AMD. Blue light-filtering IOLs prevent potentially damaging light from reaching the retina following cataract surgery.

Data Review Methodology

The authors conducted a systematic literature review to identify papers on risk and/or benefits of implanting blue light-filtering IOLs. Their search of the medical literature, using relevant key words, identified 56 articles that were published between 1962 to 2009. The results of this literature search are succinctly summarized in this review article, "Blue-Blocking IOLs: A Complete Review of the Literature."

Blue Light-Filtering IOLs

UV-light blocking lenses, including IOLs that filter harmful blue light, were designed to optimize intraocular performance and patients' results. In their comprehensive review, the authors provide cataract surgeons with the information they need to evaluate available information and reach conclusions about the benefits and potential risks of choosing a blue light-filtering IOL. Taken together, the evidence suggests that theoretical concerns about blue light-filtering on the basis of laboratory experiments have not been confirmed in humans after systematic study or widespread clinical use.

In clinical studies, blue light-filtering was well-tolerated, including the absence of any reported altered night vision or insomnia. This finding is important given the theoretical detrimental effects of blue light-filtering on dim light (night) vision as well as on sleep regulation (via light/dark influences on melatonin and its effect on the circadian cycle). When reviewing the published literature, it is clear that blue light-filtering IOLs have not been shown to be clinically harmful with respect to loss of visual acuity, color perception or significant loss of scotopic, photopic or mesopic sensitivities.

Ongoing studies and experience will shed further light on the tolerability of blue light-filtering and the relative benefit-risk ratio of current IOLs, including their ability to help prevent age-related diseases and potentially eye melanoma.

Cataracts and Their Surgical Removal

An estimated 20 million Americans aged 40 years and older (1 of every 6 persons in this age range) have a cataract in one or both eyes (prevalence >50% by age 80), with the number projected to exceed 30 million by 2020. Cataracts are a significant cause of impaired vision (blurred images that were once sharp, poor night vision) as well as the leading cause of blindness.

Surgical removal of cataracts is the most frequently performed surgery in the U.S., with approximately 2.8 million cataract surgeries performed each year in the U.S. Vision is almost universally improved immediately following cataract removal. The relationship between cataract surgery and macular degeneration is still being debated. However, in some studies, cataract surgery has been associated with increased subsequent risk for macular disease, perhaps due to increased transmission of potentially injurious short-wavelength (blue) light to the retina. New innovations, such as blue light-filtering IOLs, are potentially beneficial for preserving macular health and warrant continued investigation.