WIT STUDY SHOWS LENS IMPLANT INCREASES EYE PIGMENT THAT MAY PROTECT AGAINST
Age-related Macular Degeneration (AMD) - Leading Cause of Vision Loss
& Blindness Affects c80,000 Irish adults
Results of a new study show that implanting special lenses at the time of
cataract surgery increases a nutritional component of the eye, which may
protect against the development and/or progression of age-related macular
Conducted by leading ophthalmology and vision researchers from the Macular
Pigment Research Group (MPRG) at Waterford Institute of Technology (WIT),
these results are published in the October 2009 issue of the US-based
journal Investigative Ophthalmology & Visual Science (IOVS).1
AMD is a disease affecting the central part of the retina and is the leading
cause of vision loss in the developed world2. It is estimated that around
80,000 Irish adults have AMD and a further 30,000 people may have AMD but do
not realise that they are sufferers.
"Blue-light-filtering lenses filter and block damaging blue-light from
reaching the retina, which could potentially reduce vision loss and improve
the quality of life for millions of older patients," said the study's chief
investigator, John Nolan, Fulbright Scholar, BSc, PhD, deputy director,
"These findings represent an important first step in fully realising the
benefits of blue-light-filtering in improving macular pigment, which is a
nutritional component of the eye. An ever-growing body of scientific
evidence suggests that macular pigment plays a role in reducing the onset
and progression of AMD," he said.
Dr. Nolan and fellow MPRG researchers discovered an increase in macular
pigment levels shortly after cataract surgery among the study patients who
had these special blue-light-filtering lenses implanted.1
"Since prolonged and cumulative exposure to blue light is harmful to the
retina, increased levels of macular pigment are considered to play a role in
protecting against the processes that cause age-related blindness, including
AMD," said Dr. Nolan.
According to the study, the potential benefits of increased macular pigment
and/or decreased progression of AMD would begin at the time of cataract
surgery and are expected to continue over a patient's lifetime.1 This is
especially meaningful as cataract surgery is performed annually in millions
of older persons who live for many years after the procedure, as well as
those who have the surgery at an earlier age.2 The researchers note that
further studies are needed to confirm the clinical benefit of their
About the Study
Mr. Stephen Beatty (Consultant Ophthalmologist at the Whitfield Clinic in
Waterford), Dr. Nolan and colleagues conducted a prospective study in which
42 patients scheduled for cataract surgery were implanted with a blue
light-filtering acrylic IOL or a standard acrylic IOL (control). Macular
pigment optical density was measured by a reliable method (heterochromatic
flicker photometry) and serum concentrations of the macular carotenoids were
quantified by a scientific procedure known as 'high-performance liquid
chromatography' prior to surgery and then at several post-procedural time
points over a 1-year follow-up period.1
Cataract surgery in older persons, where the natural diseased lens
(cataract) is replaced with a clear artificial IOL, has been associated with
increased subsequent risk for macular disease,4 perhaps due to increased
transmission of potentially injurious short-wavelength (blue) light to the
Therefore, lens manufacturers have incorporated a blue-light filter into
IOLs to help reduce photo-oxidative retinal injury and thereby reduce the
risk of new-onset AMD and/or its progression. Evidence suggests that
photo-oxidative stress is important in the development of AMD.5 The
likelihood of retinal damage is highest for short-wavelength light (blue
light). Several parts of the eye, most importantly the lens, act as filters
to block short-wavelength light from reaching the retina.4
Macular pigment is thought to protect against AMD because it absorbs
short-wavelength (blue) light before it reaches photoreceptors in the retina
and because of its antioxidant properties (decreases oxidative stress by
quenching free radicals). Portions of the eye behind macular pigment are
exposed to approximately six times the amount of blue light in persons
having the lowest levels of macular pigment, as compared to those with the
highest levels 5. Macular pigment is obtained entirely from the diet and
transported to the retina via the blood. Ongoing research is being conducted
to determine the extent a person's diet may affect AMD. However, the data
available to date is in support of such a notion.5
About Cataracts and AMD
As the aging population grows and becomes a larger percentage of the overall
population, age-related diseases such as cataracts and AMD will become more
Surgical removal of cataracts - lens that have become clouded from buildup
of protein - is the most frequently performed surgery in the U.S.7, with
more than 6 million cataract surgeries currently performed each year in the
U.S. and Europe combined.7,8 While vision is almost universally improved
immediately following cataract removal, implantation of lens that does not
filter harmful short wavelength (blue) light may hasten the progression of
AMD,5 In the region of 80,000 Irish adults have AMD and a further 30,000
people may have AMD but do not realise that they are sufferers.
AMD affects part of the back of the eye called the macula, the central part
of the retina. The central vision of affected individuals becomes blurry or
wavy and can be eventually lost, which severely alters their quality of
life.9, 10. Approximately 25-30 million individuals are affected worldwide,
with the number estimated to triple in the next 25 years11.
For more information please contact Brian Nolan, Bance Nolan Ltd, (051)
The study conducted by the researchers at WIT's MPRG was published in the
October 2009 issue of Investigative Ophthalmology and Visual Science in the
United States. For more information on the study, the abstract can be
accessed at: http://www.iovs.org/cgi/content/abstract/50/10/4777.
As part of the Department of Chemical and Life Sciences at WIT, the MPRG is
one of the leading research centers in the world investigating macular
pigment and its potential role in preventing AMD and enhancing visual
performance. The work of the MPRG has received both national and
international recognition, reflected in research prizes, scholarships, grant
support and peer-reviewed publications (over 30 high-impact scientific
publications on this topic). The MPRG currently consists of ten members;
researchers within the group cover a wide variety of disciplines including
ophthalmology, vision science, optometry, chemical and biological sciences,
statistics and nutrition.
1. Nolan J, O'Reilly, P, Loughman, J, et al. Augmentation of macular
pigment following implantation of blue light-filtering intraocular lenses at
the time of cataract surgery. Investigative Ophthalmology & Visual Science.
2. World Health Organization (WHO). Priority eye diseases. Available
at: http://www.who.int/blindness/causes/priority/en/index8.html. Accessed
October 20, 2009.
3. Algvere PV, Marshall J, Seregard, S. Age-related maculopathy and the
impact of blue light hazard. Acta Ophthalmol Scand. 2006;84(1):4-15.
4. Wang JJ, Klein R, Smith W, Klein BE, Tomany S, Mitchell P. Cataract
surgery and the 5-year incidence of late-stage age-related maculopathy:
Pooled findings from the Beaver Dam and Blue Mountains eye study.
5. Bartlett H, Eperjesi F. Macular pigment: The role of xanthophylls
in preventing AMD. OT. Available at: www.macuscope.com/Eperjesi_19506.pdf.
Accessed October 15, 2009.
6. Centers for Disease Control and Prevention (CDC). Why is vision loss
a public health problem? At:
October 20, 2009.
7. American Society of Cataract and Refractive Surgery & American
Society of Ophthalmic Administrators (ASCRS & ASOA). Fact Sheet-Cataract
Surgery & Prostate Drug Complications. At:
tate-Drugs-and-Cataract-Surgery.pdf. Accessed October 20, 2009.
8. European Society of Cataract and Refractive Surgeons (ESCRS).
Revised ESCRS guidelines could save sight of thousands of cataract patients
each year. At:
Accessed October 20, 2009.
9. National Institutes of Health (NIH). Leading causes of blindness.
8pg14-15.html. Accessed on October 20, 2009.
10. National Eye Institute (NEI). Age-related macular degeneration. At:
http://www.nei.nih.gov/health/maculardegen/armd_facts.asp. Accessed October
11. AMD Alliance International. AMD fact sheet. At:
October 15, 2009.
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