Category: Eye Conditions

Sunlight and lack of antioxidants increases risk of age-related eye disease

It is generally accepted among health providers that sunlight, blue light in the visible spectrum, are contributing factors to the development of macular degeneration – and use of wrap around sunglasses, amber in color, is the foremost recommendation for macular degeneration patients.

Researchers have further determined that blue light entering the eye combined with low levels of blood antioxidants heightens the risk. They measured vitamin E & C levels in the blood of over 4,700 elderly patients (average age 73 years), took pictures of their retinas, and reviewed questionnaires they had filled out including sun exposure.

The researchers found that 2% of the patients had advanced macular degeneration, and half had early AMD. They also found that the patients who had exposure to sunlight (including blue light) alone were not more likely to develop AMD, but those who had both blue light exposure and low levels of antioxidants (zeaxanthin, vitamin E, and vitamin C) were 3.7 time as likely to develop advanced macular degeneration.

The researchers’ conclusion was that both sunglasses protection and key antioxidants in the diet is necessary to prevent macular degeneration.

Editor’s Note:  We recommend amber tinted sunglasses, which most effectively block blue light and which are also UV resistant.  Wrap around glasses are best.

Published:

1. Nutrition, Sensory on Thu October 16, 2008

2. Fletcher AE, Bentham GC, Agnew M.Sunlight Exposure, Antioxidants, and Age-Related Macular Degeneration. Arch Ophthalmol. 2008;126:1396-1403.

Researchers: Astrid E. Fletcher, PhD, of the London School of Hygiene & Tropical Medicine and associates.

For more related studies, see the “Research” section at www.naturaleyecare.com

Prism Eyeglasses May Help Improve Vision of Patients with Hemianopia

Hemianopia is a blindness in one half of the visual field due to damage of the optic pathways in the brain. This damage can result from brain injuries caused by stroke, tumor or trauma.  A patient with hemianopia may be unaware of what he or she cannot see and may frequently bump into walls, trip over objects or walk into people on the side in which the visual field is missing.

Prism eyeglasses were invented by Dr. Eli Peli of the Schepens Eye Research Institute, an affiliate of Harvard Medical School, to assist patients with hemianopia.  Dr. Peli attached small high power prisms on the top and bottom of one spectacle lens, leaving the center of the lens untouched. The prisms pull in images missing from the visual field above and below the line of sight on the side of the vision loss.  The prisms alert the patient to the presence of a potential obstacle, so that the patient can then move his/her head and eyes to examine the prism-captured image directly through the clear center of the lens.

In the trial, 32 of 43 participants (74%) who were fitted with prism glasses continued wearing the glasses at week six; at 12 months, 20 (47%) were still wearing the spectacles eight hours daily and rating them as “very helpful” for obstacle avoidance.

A larger study is currently underway to evaluate a newer model of the eyeglasses. 

SOURCE: “Community-Based Trial of a Peripheral Prism Visual Field Expansion Device for Hemianopia”, Bowers, et al, Archives of Ophthalmology, 2008, vol. 126, no5, pp. 657-664.

WNT Signaling Protein May Play Key Role in Glaucoma

A new study demonstrates that increased protein expression (DNA to RNA to polypeptide to protein) of the protein sFRP-1 may be a causal factor for higher IOP in patients with glaucoma.  This protein inhibits that capacity of cells to signal properly.

Researchers found this result by analyzing eye tissue from glaucoma patients and if they applied sFRP-1 to donor eye tissue in lab conditions, these eye tissues has less fluid outflow compared to normal eyes. The lab eyes also had less expression of another protein, WNT, involved in the signaling process

The researchers further tested their premise with lab mice who were genetically altered  to express sFRP-1 in their eye tissue – the result was that the mice also had higher IOPs.  They were able to reverse and thus resolve the problem in the lab mice by addressing the issue of WNT signaling.

Read more about glaucoma, including information on lifestyle choices and nutrition for maintaining healthy vision.

Researchers: Alcon Research Ltd. and the University of Iowa

Published: “Increased expression of the WNT antagonist sFRP-1 in glaucoma elevates intraocular pressure”, Wang, et al, Journal of Clinical Investigation, 118(3): 1056-1064 (2008).

Another Study on Antioxidants: Bilberry May Ward Off Cataracts and Macular Degeneration

Research shows bilberry extract helps fight against macular degeneration and cataracts in lab rats

Cataracts and macular degeneration are the major cause of vision deterioration in the elderly. A study by Russian scientists shows that taking bilberry supplements may help ward off these diseases.

Researchers used a particular strain of lab rats (OXYS rats) capable of reproducing many of the key features of human age-related cataracts and macular degeneration. From 1.5 to 3 months, these rats were given either a control diet or a diet supplemented with bilberry extract.

At 3 months, more then 70% of the rats in the control group had cataract and macular degeneration. Rats in the group given bilberry extract had no impairments in the lenses and retina.

Bilberry is also known as European blueberry, and is closely related to North American wild and cultivated blueberries and huckleberries. Bilberry is known to be a potent antioxidant and has been shown to help other vision problems such as glaucoma.

Results suggest that long-term supplementation with bilberry extract is effective in prevention of macular degeneration and cataract.

Read more research on cataracts and macular degeneration

Source: “Dietary supplementation with bilberry extract prevents macular degeneration and cataracts in senesce-accelerated OXYS rats”, Fursova et al, Adv Gerontol, 2005; 16: 76-9.

More Evidence that Antioxidants Help Fight Eye Diseases Such as Cataract

Antioxidants not only help prevent some eye diseases, they may also help limit progression of the diseases

It’s known that taking antioxidants helps delay the onset of some eye diseases associated with aging, such as cataract. Now researchers believe that antioxidants can be effective if damage to retinal tissue has already set in.

Researchers at the University of Maryland School of Medicine studied the effects of reactive oxygen species (ROS)-induced damage to retinal tissue. An increase in ROS levels can result in significant damage to cell structures — a situation known as oxidative stress. Oxidative stress is a significant risk factor in the development of many eye diseases associated with aging.

Since the formation of cataract is a well-defined progressive disease, believed to be related to a continued generation of ROS in the aqueous humor, the researchers hypothesized that even a late start with an appropriate antioxidant could halt the process and delay cataract development and vision impairment.

The results? Adding pyruvate — known to be an effective ROS scavenger — to lens cultures after lenses had sustained 50% damage was significantly effective in preventing progress.

Pyruvate can be found in foods such as red apples, and to a lesser extent, in dark beer and some cheeses.

Learn more about antioxidants

SOURCE:  “Oxidative damage to lens in culture: reversibility by pyruvate and ethyl pyruvate”, Varma, et al, Ophthalmologica, 2008; 222 (3):194-198.

Update: More Evidence on Antioxidants & Cataract

Cataracts are the leading cause of blindness around the world.  Studies suggest that oxidation is responsible for much of the damage to the lens and that antioxidants might protect the lens against formation of cataract.

Scientists at the University of Sydney and the University of Melbourne in Australia have released their investigation of the relationship between antioxidant nutrient intakes and the incidence of age-related cataract.

During 1992–1994, 3654 people aged 49 years or older attended baseline examinations as part of the Blue Mountains Eye Study.  Of these, 2464 (67.4%) of the participants were evaluated again at either 5 years or 10 years.  At each examination, lens photography was performed and food-frequency questionnaires were administered.  Antioxidants, including beta-carotene, zinc, and vitamins A, C, and E, were assessed. Cataract was assessed at each examination from lens photographs with the use of the Wisconsin Cataract Grading System.

Participants whose total intake of vitamin C (diet as well as supplements) was in the top 20% of the group had a reduced risk of nuclear cataract.  An above-median intake of combined antioxidants (vitamins C and E, beta-carotene, and zinc) was also associated with a reduced risk of incident nuclear cataract.

Study authors concluded that higher intakes of vitamin C or the combined intake of antioxidants had long-term protective associations against development of nuclear cataract in this older population.

SOURCE:  Tan, et al, Antioxidant nutrient intake and the long-term incidence of age-related cataract: the Blue Mountains Eye Study,  American Journal of Clinical Nutrition, Vol. 87, No. 6, 1899-1905, June 2008.

 

 

Millions May Be Driving with Uncorrected Visual Impairments

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.

 

Half of U.S. Adults Lack 20/20 Vision

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. With an auto-refractor the researchers  obtained refractive error data on a sample of 12,010 US adults in the 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:

 

  • Nearsightedness was more prevalent in women (39.9%) than in men (32.6%) among 20- to 39-year-old participants. 
  • People 60 years or older were less likely to have nearsightedness and more likely to have farsightedness and/or astigmatism than younger persons. 
  • Nearsightedness was more common in non-Hispanic whites (35.2%) than in non-Hispanic blacks (28.6%) or Mexican Americans (25.1%).

 

SOURCE: Susan Vitale, PhD, MHS; Leon Ellwein, PhD; Mary Frances Cotch, PhD; Frederick L. Ferris III, MD; Robert Sperduto, MD; Arch Ophthalmol. 2008;126(8):1111-1119.

Even Moderate Vision Loss Increases the Risk of Injuries in Older People

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.


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.

Omega-6 Fatty Acids May Help Relieve Contact Lens-Associated Dry Eye

A 2008 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 another trial 26 dry eye patients were divided randomly  into two equal sections. One section received 28.5 mg linoleic acid and 15 mg gamma-linolenic acid twice a day for 45 days while the other control section was given a placebo for the same period.

The results? Researchers found that the therapy reduced inflammation on the surface of the eye 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.

Breastfeeding May Reduce the Risk of Myopia in Children

Myopia, also called near-sightedness, is a condition in which distant objects appear blurred. Myopia is the leading cause of visual impairment in developed countries, and is present in over 30 million adults in the U.S.

Researchers in Singapore have found that children who are breastfed are less likely to have myopia. Breast milk is the main source of many micronutrients including docosahexaenoic acid (DHA). DHA is important for photoreceptor and cortical neuronal development, which play a major role in whether children become nearsighted.

Researchers studied 797 children aged 10 to 12 as part of the Singapore Cohort Study of the Risk Factors of Myopia, including 418 children who had been exclusively breast-fed, and 379 who had not. They performed cycloplegic autorefraction and diagnosed myopia as spherical equivalent refraction of at least -.05 diopters.

Children who were breastfed had a lower prevalence of myopia (62.0%) than children who were not breastfed (69.1%). This association held even after researchers controlled for factors such as the parents’ nearsightedness, maternal age at delivery and birth weight.

Read more about myopia, including recommended vitamins and other nutritional products.

SOURCE: The Journal of the American Medical Association, Vol. 293 No. 24, June 22/29, 2005