ATARACT IOLs Intraocular Lens Replacement
in a by Gerardo Sison
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World of Blue Light
n an aging population, the growing need for cataract surgery and replacement intraocular lenses (IOLs) has become more apparent. However, due to variabilities in macular pigments, crystalline lens changes and light exposure, there may be more at stake. Many patients needing intraocular lens replacement may be at an increased risk of ocular damage due to photo-oxidative effects from short-wave blue light. Intraocular lens solutions for agerelated macular degeneration (AMD) have been used throughout the years and resulted in the development of blue light-filtering intraocular lenses (BLF IOLs). These BLF IOLs may help protect against ocular damage, prevent visual performance issues and improve glare discomfort. Dr. Billy Hammond, PhD, professor and neuroscientist at the University of Georgia, initially studied the effects of dietary compounds such as lutein and zeaxanthin on eye and brain health. In a review conducted earlier in 2019, he reported the effects of BLF IOLs
and their use in AMD patients needing cataract surgery.
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Blue Light in Nature “A lot of animals use yellow filters to filter blue light,” said Dr. Hammond. “Some fish have yellow corneas, which is a fairly common way to adapt to ecological niches where visual function could be impaired by bright sunlight and exposure to short-wave light.” The human and animal ocular lenses have become strongly affected by blue light and its influence on visual function and ocular tissue. Not only are humans susceptible to blue light effects, but animal species such as prairie dogs and squirrels have developed filter adaptations to prevent damage from constant exposure. Naturally occurring macular pigments such as zeaxanthin and lutein are found in the macula and absorb short-wave visible light (400-520nm). These macular pigments are found in concentrated proportions in and around the fovea, screening central cones
December/January 2020
and rods of the retina. Research has found that dietary lutein and zeaxanthin supplementation can help improve visual functions in conditions with glare compared to placebo. According to Dr. Hammond, one problem is that over time, humans have become deficient in lutein and zeaxanthin pigments, which has only compounded the problem that blue light elicits. “Blue light is not only deleterious for long-term damage,” he said. “It interferes with visual functions in various ways.”
Combating Photo-Oxidative Damage Ocular damage often contributes to the etiology of several diseases such as pinguecula/pterygium and photokeratitis. Damage caused by continuous exposure to short-wave blue light is also associated with conditions such as age-related cataracts and AMD. In older adults, photosensitizers to specific wavelengths of blue light can be especially damaging to the retina.
