Natural Eye Care

Researchers at the University of Pennsylvania School of Medicine have created the first animal model of age-related macular degeneration (AMD) caused by a mutation known to produce disease in people.

AMD is the most common cause of vision loss in elderly people, affecting more than 10 million people in the U.S. and about 50 million world-wide. Because AMD develops late in life (patients typically show symptoms of AMD after age 60), it is a difficult condition to investigate.

Although some forms of AMD are inherited, one type is thought to be caused by a mutation in the Efemp1 gene. Researchers introduced the disease-causing mutation into the Efemp1 gene of mice. These Efemp1-mutant mice develop the same basal deposits as people with AMD.

It is believed that these mice will provide a means to study how basal deposits form and what they are made of. The mice can also be used to test potential treatments to prevent basal deposit formation.

“To better develop treatments for preventing the progression of AMD, we need to understand the real biochemical details of how AMD occurs,” says lead author Eric A. Pierce, MD, PhD, Associate Professor of Ophthalmology at Penn’s K.M Kirby Center for Molecular Ophthalmology. “To do that, we need a model, and now we have one.”

Learn more about age-related macular degeneration (AMD)

Read other studies about macular degeneration

SOURCE: Model To Study Age-related Macular Degeneration Could Pave Way For Better Treatment, Pierce et al, University of Pennsylvania School of Medicine (2007, October 10).

Regular Eye Exams are Vital for Driver Safety

11 million Americans with could be driving with uncorrected vision problems. Depending on where those drivers live, their last DMV-required vision screening could have been eighteen years ago; some may never have had one at all, according to a report by the Vision Council of America (VCA). 

 “Our already crowded roads are made that much more dangerous by drivers with uncorrected vision problems getting behind the wheel,” said Ed Greene, VCA chief executive officer. “Since 85 percent of the information needed for safe driving is visual, regular eye exams are an important part of driver safety.”

The VCA report “Keeping Our Eyes on the Road,” reviewed vision screening laws and found them to be inconsistent. While some states require vision screenings every time drivers renew their licenses, other drivers may go as long as 18 years before they are required to have their vision re-checked. Nine states require no vision screening at all for license renewal. In the absence of standards for vision screenings, drivers must be responsible for maintaining good vision.

“We rely on our eyes every time we step into a car; especially our peripheral vision, depth perception and focusing skills,” said Greene. “This link between vision and driving makes it essential for motorists to take steps to maintain healthy vision, just as they take other safety precautions on the road.”

 “People often don’t notice gradual changes in their vision which, over time, can impede their ability to drive safely,” said ophthalmologist Elaine G. Hathaway, M.D. “Checking your eyes is important not only to determine proper vision correction, but also to detect cataracts and sight-threatening diseases such as glaucoma and macular degeneration so they can be properly treated.”

VCA suggests the following tips to help drivers stay safe on the roads:

• Take breaks when driving long distances to reduce eye strain and fatigue
• Use sunglasses with at least 99 percent UV protection when appropriate
• Investigate anti-reflective or polarized lenses to allow more light to enter the eye and to minimize glare
• Keep headlights, taillights and windshield (both inside and outside) clean
• Receive regular eye exams by an eye care professional to ensure that your eyes stay healthy and your prescription remains current

Regardless of what your state requires, VCA recommends that drivers receive a regular comprehensive eye exam by an eye care professional to maintain healthy vision.  With regular vision care, drivers can prevent poor sight from putting themselves and their loved ones at risk on the road.

SOURCE:  Vision Council of America, Keeping Our Eyes on the Road, November 19, 2007.

New study shows that supplementing with bilberry can helps lower intraocular pressure (IOP). Uncontrolled high IOP is the major cause of vision loss for those with glaucoma.

In a study performed by researchers from the University of Chieti-Pescara in San Valentino, Italy, thirty-eight subjects with IOP were either given bilberry and French maritime pine bark (20 subjects) or were not treated (18 subjects)¹. The visual acuity, IOP, and ocular blood flow were measured at two, three, and six months. After two months of supplementation the mean IOP decreased. No side effects were observed and ocular blood flow improved. An improved ocular blood flow may contribute to the prevention of glaucoma. The results of this study indicate that bilberry and pine bark may represent a safe preventative intervention for lowering the risk for developing symptomatic glaucoma by controlling IOP and improving ocular blood flow. This helps to support research for other preventative nutritional approaches to major eye health, such as cataract, age-related macular degeneration, and retinopathy.

For more information on nutrition and glaucoma, go to www.naturaleyecare.com

Researchers in Italy have released a study indicating that nutritional supplements of bilberry and French maritime pine bark can help reduce intra-ocular pressure (IOP). While several factors contribute to the development of glaucoma, elevated IOP is one of the greatest risks. An improved ocular blood flow may help prevent glaucoma.

Authors of the study from the University of Chieti-Pescara in Italy studied thirty-eight subjects with intraocular hypertension. Twenty subjects were given bilberry and French maritime pine bark; eighteen subjects were not treated. The visual acuity, IOP, and ocular blood flow were measured at two, three, and six months. After two months, the group taking the supplements showed a decrease in the mean IOP. No side effects were observed and ocular blood flow improved.

Having reviewed the results, these researchers believe that food supplements of bilberry and pine bark may represent a safe preventative intervention for lowering the risk of developing glaucoma by supporting a healthier pressure in the eyes.

Read more research on glaucoma

Learn about bilberry and other natural supplements for healthy vision

SOURCE: “Effects of Mirtogenol on ocular blood flow and intraocular hypertension in asymptomatic subjects”, Robert Steigerwalt Jr., et al, Molecular Vision 2008; 14:1288-1292.

Results from the vision component of the Women’s Antioxidant and Folic Acid Cardiovascular Study, also known as WACS, were presented at the ARVO 2007 Annual Meeting. Researchers from the Brigham and Women’s Hospital and the National Eye Institute concluded that the data from this randomized trial indicate that supplementation with folic acid, vitamins B6 and B12 reduced the risk of AMD in women with cardiovascular disease (CVD) (1).

These three B-vitamins, particularly folic acid, have been shown to reduce high levels of the naturally occurring compound, homocysteine. Research has implicated elevated plasma levels of homocysteine in the development of vascular diseases including choroidal neovascularization in exudative AMD.

Study Design and Methods: A total of 8,171 female health professionals, 40 years or older with pre-existing CVD or having at least three risk factors for the disease were enrolled in the trial. The women were randomized to receive vitamin C (500 mg daily), vitamin E (600 IU every other day), beta-carotene (50 mg every other day) or placebo in the WACS secondary prevention trial.

Of this group, 5,422 women were subsequently randomized to also receive a placebo or folic acid (2.5 mg), vitamin B6 (50 mg) and vitamin B12 (1 mg) daily. Of these women, 5,205 did not have a diagnosis of AMD, and were included in this analysis. There were two primary outcome measures: a) confirmed AMD (self reported and supported by medical record evidence of an AMD diagnosis after randomization) and b) confirmed AMD with vision loss - defined as vision to 20/30 or worse which was attributable to this condition.

Results: A total of 137 cases of AMD were documented, including 69 cases of AMD with vision loss, during an average of 7.3 years of treatment and follow-up. Fifty-five cases occurred in the treatment group, while the placebo group had 82 documented cases. Relative risk was 0.66 (95% confidence interval, p = 0.02). For AMD with vision loss, there were 26 cases in the B-vitamin group compared to 43 among placebo takers. Relative risk was 0.60 (95% confidence interval, p = 0.04). In summary, women taking supplemental B vitamins were 34% less likely to develop AMD and 40% less likely to have AMD-related vision loss than women in the control group.

Note: While very high doses of the 3 B vitamins were tested in this group of women with CVD, lower doses may well have been effective. For example, a placebo-controlled, randomized dose response study in people with a history of CVD found that the decrease in homocysteine was proportionate to the folate dose up to - and not beyond - 800 mcg daily (2). This dose achieved an average 23% drop in plasma homocysteine compared to placebo - a drop of about the same magnitude found in trials using up to 5,000 mcg folate daily (3). Additionally, excessive amounts of folic acid have recently been implicated in colorectal tumor growth (4,5).

References :
Christen WG, et al. Folic acid plus B-vitamins and age-related macular degeneration in a randomized trial in women. Invest Ophthalmol Vis Sci 48:E-abstract 1152, ARVO, 2007.
Wald DS, et al. Randomized trial of folic acid supplementation and serum homocysteine levels. Arch of Internal Med 161:695-700, 2001.
Homocysteine Lowering Trialists’ Collaborative. Lowering blood homocysteine with folic acid based supplements: meta-analysis of randomized trials. BMJ 316:894-8, 1998.
Mason JB, et al. A temporal association between folic acid fortification and an increase in colorectal cancer rates may be illuminating important biological principles: A hypothesis. Cancer Epidemiol Biomarkers Prev 16:1325-9, 2007.
Cole BF, et al. Folic acid for the prevention of colorectal adenomas. JAMA 297:2351-9, 2007.
Cook NR, et al. A randomized factorial trial of vitamins C and E and beta carotene in the secondary prevention of cardiovascular events in women: Results from the WAC Study. Arch of Int Med 167:1610-18, 2007.

A new study has found that common vision problems known as refractive errors (nearsightedness, farsightedness, and astigmatism) affect half the adult U.S population.

The study authors, led by Susan Vitale of the U.S. National Eye Institute, analyzed data collected by the U.S. Centers for Disease Control and Prevention’s ongoing National Health and Nutrition Examination Survey. In this study an autorefractor was used to obtain refractive error data on a nationally representative sample of 12,010 adults in the U.S. population between 1999 and 2004.

Of the participants (all aged 20 or older), researchers found:

• 3.6% had hyperopia (farsightedness),
• 33.1% had myopia (nearsightedness), and
• 36.1% had astigmatism (an irregular corneal curve)

Other findings:

A study conducted in North India found that people with low levels of antioxidants had higher levels of cataracts.

Several recent studies have shown antioxidants are important in fighting macular degeneration. We are now learning how important these same antioxidants may be for preventing cataracts as well.

How can you boost your antioxidant levels? Eat more fruits and vegetables, especially those high in yellow, orange and dark green pigments.

In this new study 1,112 participants aged 50 or older were interviewed for risk factors (tobacco, alcohol, biomass fuel use, sunlight exposure and socioeconomic status) and underwent lens photography and blood sampling to measure antioxidant levels.

Researchers found significant inverse associations between cataracts and the antioxidants vitamin C, zeaxanthin, lutein, lycopene, alpha- and beta-carotene and beta-cryptoxanthin; people with lower levels of these antioxidants had higher rates of cataracts.

Read more about antioxidants

Learn more about cataracts

Learn more about food sources for nutrients crucial for good eye health

Read more research on antioxidants and their importance for vision

SOURCE: Dherani M, Murthy GV, Gupta SK, et al. Blood levels of vitamin C, carotenoids and retinol are inversely associated with cataract in a North Indian population. Invest Ophthalmol Vis Sci 2008;49(8):3328-35.

Reducing cardiovascular risk factors such as high blood pressure may reduce the risk of Age-Related Macular Degeneration (AMD).

A study of Latino adults in Los Angeles looked at the association between cardiovascular risk factors and advanced AMD.�

AMD was tested via intraocular pressure (IOP) measurement and stereoscopic macular photography in 5,875 participants. Hypertension was defined as either a history of hypertension or systolic blood pressure (SBP) higher than 140 mmHg +/- diastolic blood pressure (DBP) 85 mmHg or higher. Ocular perfusion pressure (OPP) was defined as the difference between mean arterial blood pressure and IOP.

Once researchers adjusted for age, gender and cigarette smoking:
� • higher DBP and uncontrolled diastolic hypertension were associated with exudative AMD
� • higher OPP was associated with a decreased risk of geographic atrophy (GA)
� • low pulse pressure was associated with a lower risk of exudative AMD
� • obesity was associated with increased retinal pigment.�

Researches suggest that in Latinos, cardiovascular risk factors may play a role in advanced AMD. Actions aimed at reducing these risk factors may also have a beneficial impact on the risk of having early and advanced AMD.�

Read more about AMD

See other research about macular degeneration�

SOURCE: Fraser-Bell S, Wu J, Klein R, et al. Cardiovascular risk factors and age-related macular degeneration: The Los Angeles Latino Eye Study. Am J Ophthalmol 2008;145(2):308-16�

It’s no surprise that failing eyesight leads to more accidents, but a new study shows early intervention to correct even minor visual impairment may prevent injury.

Decreased vision in older people is commonly related to an increased risk of falling, and a new study has scientifically evaluated this link. The goal of the study was to determine whether visual loss was associated with a higher incidence of injurious accidents and whether walking speed or physical activity influenced this association.

416 people aged 75 to 80 years were tested for visual acuity. Those testing at less than 20/60 in the better eye (with spectacle correction when necessary) were defined as visually impaired. Those tested with visual acuity between 20/60 and 20/40 were defined as having lowered vision. Those testing at greater than 20/40 were defined as having normal visual acuity.

Hospital records of accidents with injuries were monitored for ten years, during which 239 participants (58%) suffered at least one injurious accident. Even considering other factors (age, gender, eye-related diseases, diabetes and cardiovascular diseases), the risk of injurious accidents for participants with lowered vision was 1.45 compared with those with normal visual acuity.

Interestingly, participants with visual impairment did not have an increased risk for accidents over those with lowered vision, and neither walking speed nor physical activity had a mediating effect on the relationship between visual loss and accidents.

Researchers have therefore concluded that lowered vision is a risk factor for accidents in older people independent of mobility and physical activity.

In light of this research, early intervention strategies such as proper correction of vision or cataract extraction are truly important in preventing accidents in the elderly.

Read more about vision loss prevention

SOURCE: Kulmala J, Era P, Parssinen O, et al. Lowered vision as a risk factor for injurious accidents in older people. Aging Clin Exp Res 2008;20(1):25-30.

A recent study shows that consumption of omega-6 fatty acid may help alleviate dry eye symptoms and improve overall lens comfort in patients suffering from contact lens-associated dry eye.

Researchers evaluated the effects of oral treatment with omega-6 fatty acids in the form of evening primrose oil (EPO) on subjective symptoms, ocular surface signs and tear film characteristic in patients with contact lens-associated dry eye.

76 female soft contact lens wearers were treated for six months either with omega-6 fatty acids in the form of EPO or placebo (olive oil). The patients were given three examinations (baseline, three and six months) to test tear film characteristics (tear meniscus height, break-up time), meibomian gland function (lipid layer thickness and quality) and ocular surface parameters (hyperemia and staining). At each examination the women were given a questionnaire relating to lens comfort and dry eye symptoms.

The EPO group showed a significant improvement in the specific symptom of “dryness” at three and six months as well as a significant improvement in overall lens comfort at six months. Tear meniscus height was increased in the EPO group at six months relative to baseline, although all other objective signs were unchanged.

These findings support a 2003 study on omega-6 fatty acids which evaluated the effect of systemic linoleic acid (LA) and gamma-linolenic acid (GLA) on patients with dry eyes.

GLA is an essential fatty acid in the omega-6 family that is found primarily in plant-based oils, such as evening primrose oil, black currant seed oil, and borage seed oils. Essential fatty acids help the body’s natural ability to fight inflammation, but cannot be made in the body and must be obtained from food. LA, another omega-6 fatty acid, is found in plant oils such as safflower oil and is converted to GLA in the body.

In a randomized clinical trial, 26 patients with dry eye (aqueous-deficient keratoconjunctivitis sicca) were randomly divided into two groups of 13 patients each. The study group received tablets containing LA (28.5 mg) and GLA (15 mg) twice daily for 45 days; the control group received a placebo tablet for 45 days.

The results? Researchers found that therapy with LA and GLA and tear substitutes reduced ocular surface inflammation and improved dry eye symptoms.

Read more about dry eye and studies on dry eye

SOURCE: Oral Omega-6 Essential Fatty Acid Treatment in Contact Lens Associated Dry Eye. Kokke, et al. Cont Lens Anterior Eye 2008;31(3):141-6.

SOURCE: Systemic Linoleic and Gamma-Linolenic Acid Therapy in Dry Eye Syndrome With an Inflammatory Component, Barabino, et al.Cornea. 22(2):97-101, March 2003.