Eyes
Episodes
Dr. Rhonda Patrick covers lithium microdosing, reducing homocysteine, aluminum's link to cancer, and beta-alanine and alpha-lipoic acid supplements.
Dr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.
Dr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.
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Exercise Biomarkers Vitamin E Genetics Eyes Caffeine Folate Sulforaphane Sauna Antioxidant Dairy Polyphenol Supplements Wearable Technology RhondaDr. Rhonda Patrick covers lithium microdosing, reducing homocysteine, aluminum's link to cancer, and beta-alanine and alpha-lipoic acid supplements.
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Rhonda Ketosis Heart Disease Omega-3 Fasting Pregnancy Eyes Muscle Sauna Protein Dairy Intestinal Permeability Brown Fat Moringa SupplementsDr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.
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Rhonda Exercise Aging Sleep Telomeres Vitamin C Cholesterol Omega-3 DNA Damage Fasting Coffee Magnesium Eyes Calcium Time-Restricted Eating Breast Milk Moringa LactateDr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.
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In this clip, Dr. Rhonda Patrick describes a study in which stem cell-derived retinal cells were used to treat macular degeneration in a human.
Topic Pages
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Carotenoids
Macular carotenoids lutein and zeaxanthin concentrate in photoreceptor membranes, filter blue light and scavenge reactive oxygen, preserving retinal integrity.
News & Publications
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Age-related macular degeneration, the leading cause of irreversible blindness in older adults, affects nearly 200 million people worldwide. This progressive disease erodes central vision, which is critical for reading, driving, and other daily activities. A recent study found that glucagon-like peptide-1 (GLP-1) receptor agonists, such as Ozempic, Wegovy, or others, may double the risk of developing neovascular age-related macular degeneration, the most serious form of the disease.
Researchers analyzed health records from more than 1.1 million people in Ontario, Canada, who had diabetes and were 66 or older. They created a matched study group of about 139,000 people, comparing those who used GLP-1 receptor agonists for at least six months to similar patients who didn’t use the drugs. The researchers tracked new cases of neovascular age-related macular degeneration over three years.
They found that people who used GLP-1 receptor agonists were more than twice as likely to develop neovascular age-related macular degeneration than those who didn’t use the drugs. About 0.2% (93) of the users developed the condition, compared to 0.1% (88) of non-users. Even after accounting for other risk factors, the difference remained consistent.
These findings suggest that while GLP-1 receptor agonists provide considerable health benefits, they may also pose an overlooked risk for serious vision problems. It’s noteworthy that diabetes is an independent risk factor for macular degeneration, and this study identified associations, not a cause-and-effect relationship. Learn more about GLP-1 drugs in Aliquot #128: The Expanding Role of Weight Loss Drugs
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Red-light therapy slows myopia progression in children, reducing elongation of the eye and improving vision. bmcophthalmol.biomedcentral.com
Scientists estimate that the number of people with myopia – commonly known as nearsightedness – will be as high as 4.7 million by 2050. Correcting myopia is costly and typically involves prescription glasses, contact lenses, or refractive surgery. A recent review and meta-analysis found that repeated low-level red-light therapy improves myopia progression in children.
Researchers analyzed the findings of five randomized controlled trials investigating the effects of repeated low-level red-light therapy on myopia versus prescription glasses in children. The studies included 833 participants, about half of whom received red-light therapy. The parameters measured included axial length (distance from the front to the back of the eye), spherical equivalent refraction (the power needed to correct vision), and subfoveal choroidal thickness (thickness of the layer beneath the central part of the retina).
They found that repeated red-light therapy improved all vision parameters at multiple follow-up periods during the studies. At the 12-month follow-up assessment, the children experienced a 0.31-millimeter decrease in axial length and a 0.63 increase in spherical equivalent refraction, indicating marked improvements in myopia progression and eye structure. These findings suggest that repeated low-level red-light therapy effectively slows or reduces myopia progression in children, leading to less elongation of the eyeball and improved vision.
Red-light therapy is a form of photobiomodulation, a non-invasive, light-based therapeutic technique. Photobiomodulation employs specific wavelengths of light to stimulate biological processes within cells and tissues, triggering a cascade of physiological responses. Evidence suggests photobiomodulation has potential applications in medicine, dentistry, cosmetic procedures, and scientific research. Learn more about photobiomodulation in our overview article.
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Vision problems predict dementia risk nearly 10 years before diagnosis. www.ncbi.nlm.nih.gov
People with dementia often experience visual problems, which range in severity from difficulty seeing contrasts or colors to impaired understanding of spatial relationships. These visual problems typically manifest early in dementia, indicating that early vision testing may help identify those at risk. A recent study found that visual problems may predict dementia nearly 10 years before diagnosis.
The study involved more than 8,600 participants in a large, population-based prospective cohort. At the beginning of the study, participants took two visual sensitivity tests (simple and complex), which assess how quickly a person can process visual information and react to it. Researchers tracked the participants' cognitive and physical health for about 15 years.
They found that vision problems predicted participants' dementia risk an average of 9.6 years before a clinical diagnosis. A low score on the simple visual sensitivity test was associated with a 39 percent greater risk of developing dementia, and a low score on the complex test was associated with a 56 percent greater risk. These risks persisted even after accounting for the participants' ages. Interestingly, the vision testing was more sensitive to variables commonly associated with dementia risk (such as age, gender, and education) than traditional dementia assessments.
These findings suggest that visual problems predict future dementia risk. They also bolster previous research demonstrating that horizontal eye movements, such as those used when reading or viewing television, improve memory. Other lifestyle factors, including sleep, influence dementia risk, too. Learn more in this video featuring Dr. Rhonda Patrick.
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Eating blueberries multiple times a week slashes the risk of age-related macular degeneration by up to 64 percent. www.sciencedirect.com
Age-related macular degeneration is the leading cause of vision loss in older adults. However, evidence suggests that some dietary components reduce the risk of the disease. A recent study found that eating blueberries cuts the risk of age-related macular degeneration by 64 percent.
The study involved roughly 35,000 middle-aged and older women enrolled in the Women’s Health Study. Researchers used questionnaires to collect information about the women’s blueberry intake and eye health for about 11 years.
They found that eating blueberries one to three times a month reduced the risk of age-related macular degeneration by 10 percent, eating them once a week by 29 percent, more than once a week by 32 percent, and two or more times a week by 64 percent. Eating more blueberries didn’t show a protective effect against developing cataracts; however, higher anthocyanin intake did confer a 10 percent reduction in risk.
Blueberries are rich in anthocyanins – a class of flavonoid compounds that exert robust antioxidant and anti-inflammatory properties via hormetic effects. Learn about the hormetic effects of anthocyanin-rich blueberries as well as other hormetic compounds in this smoothie recipe video.
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Omega-3 fatty acids relieve symptoms of dry eye disease, especially when taken longer, in higher doses, and with higher EPA percentages. www.ncbi.nlm.nih.gov
Dry eye disease – an inflammatory condition characterized by a stinging, burning, or scratchy sensation in the eyes – affects roughly 8 percent of adults in the U.S. Although several treatments address dry eye symptoms, none target the underlying inflammation. A recent systematic review and meta-analysis found that omega-3 fatty acids alleviate dry eye symptoms and reduce eye inflammation.
Researchers reviewed the findings of randomized controlled trials investigating the effects of omega-3s on dry eye. Their analysis included 19 trials involving more than 4,200 patients.
They found that the duration (one to 12 months), total omega-3 dose (128 to 2,000 milligrams), and percentage of eicosapentaenoic acid (EPA, ranging from 7 to 80 percent) varied considerably among the trials. Despite this heterogeneity, the reviewers concluded that omega-3s effectively reduced dry eye symptoms, especially when taken longer, in higher doses, and with higher EPA percentages..
These findings suggest that omega-3s are viable options for treating dry eye disease. Some of these effects may be due to omega-3s' capacity to enhance tear production and restore the eyes' lipid layer by resolving dysfunction in the meibomian glands (tiny oil glands that line the eyelids' margins), collectively working to alleviate symptoms and improve overall eye health.
Omega-3 fatty acids exert robust anti-inflammatory properties, likely due to their formation of specialized pro-resolving molecules (SPMs), a broad class of metabolites that resolve inflammation. Learn more about SPMs in this clip featuring Dr. Bill Harris.
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Stem cell therapy shows promise in reversing premature ovarian insufficiency and restoring fertility, a study in mice reveals. www.technologynetworks.com
Premature ovarian insufficiency – a condition in which the ovaries fail earlier than usual – affects more than 3.5 percent of females worldwide, often due to genetics, autoimmune disorders, or exposure to certain drugs, such as those used in chemotherapy. The condition has limited treatment options, but a new study in mice suggests that induced pluripotent stem cells could help.
Induced pluripotent stem cells are stem cells that have been reprogrammed into an embryonic-like pluripotent state. They can develop into any type of human cell and are commonly used in biomedical research and treatment.
Researchers reprogrammed granulosa cells from the ovaries of mice to become induced pluripotent stem cells and then allowed them to differentiate into oocytes (immature eggs). They transplanted the oocytes into the ovaries of mice with drug-induced premature ovarian insufficiency. Then, they bred the transplanted mice with normal animals to assess their fertility.
They found that the induced pluripotent stem cells transformed into functional oocytes and ovarian cells, expressing specific markers for ovaries and germ cells. After transplantation, the animals' hormonal function and fertility normalized, and they gave birth to healthy mouse pups.
These findings suggest that induced pluripotent stem cell-derived ovarian tissue can reverse the hormonal and reproductive problems characterized by premature ovarian insufficiency. They also highlight yet another potential use for induced pluripotent stem cells in ameliorating various human diseases. Learn how induced pluripotent stem cells may help treat macular degeneration in this clip featuring Dr. David Sinclair.
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High-dose omega-3 treatment expression of Mfd2a omega-3 DHA transporter in retina and blood vessels www.sciencedirect.com
From the publication:
Most importantly, our results revealed that high-dose fish oil supplementation was able to induce the expression of Mfsd2a, a major DHA transporter in the retina on both transcriptional and translational levels, simultaneously increasing the Mfsd2a expression on the blood vessels after only three weeks of treatment. It was suggested that the low expression of Mfsd2a in the retina might be one reason why DHA therapy fails to alleviate the symptoms of diabetic retinopathy (DR) and that the combined use of Mfsd2a overexpression and DHA therapy may have synergistic effects. It is thus conceivable that the high dose fish oil supplementation can serve as a potential adjuvant in the therapies or as a prophylactic in the early stages of disease for the impaired blood-retinal barrier through the up-regulation of Mfsd2a expression.
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Early-life obesity increases the risk of macular degeneration later in life. www.sciencedaily.com
Obesity in early life induces changes in immune cells that may increase the risk of macular degeneration later in life, a study in mice has found. These changes linger even after weight loss and the restoration of normal metabolism.
Researchers fed mice a diet that promoted weight gain early in life. Then they studied the effects of having excess body fat on the animals' adipose tissue macrophages – a type of immune cell found in fat. Later, they put the mice on a diet that promoted weight loss.
They found that having excess body fat induced epigenetic changes in the macrophages that, in turn, induced an inflammatory response. This pro-inflammatory response persisted even after the mice lost weight. They also found that the macrophages could migrate from the fatty tissue to other parts of the body, including the eyes, where they could contribute to the onset of macular degeneration.
Macular degeneration is the leading cause of blindness worldwide. Having excess body fat is the second leading risk factor for macular degeneration. In fact, a person’s risk of developing macular degeneration increases by 75 percent with each 0.1 increase in their waist-to-hip ratio – a measure of abdominal obesity.
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Estrogen may increase susceptibility to inflammatory disease by negatively affecting wound healing and protective lipid mediator circuits. (2012) www.sciencedaily.com
From the article:
To make this discovery, Gronert and colleagues administered a mild abrasion injury to the front of the eye of genetically similar male and female mice, and analyzed wound healing by image analysis. To test the role of estrogen, they gave male mice estrogen eye drops and/or drugs that activate specific estrogen receptors. Gene expression of essential enzymes was quantified for the formation of protective lipid signals, specific receptors that mediate their bioactivity, as well as estrogen receptors in mouse corneas and human/mouse epithelial cell cultures. The formation of protective lipid signals was analyzed by a mass-spectrometry based lipidomic method. They found that estrogen negatively affects a highly evolved protective lipid circuit, called “15-lipoxygenase-Lipoxin A4” that has recently emerged as an important protective pathway in many diseases. This pathway balances the activity of pro-inflammatory signals to promote wound healing and to keep inflammation within safe ranges.
“This study goes a long way to explaining gender differences in inflammation and its resolution,” said Gerald Weissmann, M.D., Editor-in-Chief of the FASEB Journal. “It’s long been known that women suffer more than men from chronic inflammatory diseases such as lupus or rheumatoid arthritis; this study suggests that estrogen itself is responsible for that difference and pinpoints the molecular pathways that estrogen affects. Molecules that promote the resolution of inflammation show promise as new treatments for autoimmune disease.”
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Suppression of TLR4 gene shown in animals to protect against retinal cell death associated with acute glaucoma www.sciencedaily.com
From the article:
In the study, researchers showed that a rapid, sustained large increase in eye pressure in mice turns on a gene (TLR4) that activates a protein known as caspase-8. This signaling protein in turn triggers the production of inflammatory proteins that normally help mammals fight microbial infections.
“This immune response is a double-edge sword because, while these proteins protect us from infection in a normal situation, they stimulate apoptosis (programmed cell death) in retinal cells in cases of acute glaucoma,” said Zhang, who is also a staff physician at the Veterans Affairs San Diego Healthcare System.
To further confirm the mechanism linking high eye pressure to retinal damage, researchers showed that they could slow retinal cell death in mice with acute glaucoma by suppressing either the TLR4 gene or caspace-8 protein.
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“Pregnancy and lactation can change the maternal nutrient reserve. We evaluated the association of macular pigment optical density (MPOD) with dietary and breastmilk carotenoids in postpartum women.
MPOD measurements and dietary intake of five carotenoids were obtained from 80 mothers in the first three months postpartum. Breastmilk samples from a subset of mothers were analyzed to determine their nutrient composition. The association between MPOD and dietary or breastmilk carotenoids was quantitatively assessed to better understand the availability and mobilization of carotenoids.
Our results showed that dietary α-carotene was positively correlated with MPOD. Of the breastmilk carotenoids, 13-cis-lutein and trans-lutein were correlated with MPOD when controlled for the total lutein in breastmilk. Other carotenoids in breastmilk were not associated with MPOD. Maternal MPOD is positively correlated with dietary intake of α-carotene in the early postpartum period, as well as with the breastmilk content of lutein."
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Some people appear to age slower (or faster) than others, exhibiting vastly different age-related physical changes and disease risks. Recognition of this biological phenomenon has given rise to the concept of biological age – a measure of a person’s physiological and functional state. Scientists use a variety of means to gauge biological age, including methylation markers, gray matter volume, and facial aging. Findings from a recent study suggest that retinas provide useful biomarkers in determining a person’s biological age.
The retina is a thin, multicellular layer lining the rear, interior portion of the eye. It plays critical roles in the cascade of events involved in visual processing, converting the energy of photons of the visible light spectrum into biochemical signals and transmitting those signals to the brain. Poor retinal health is often an indicator of systemic illness, such as cardiovascular disease or nutritional deficiency.
The authors of the study viewed more than 80,000 retinal images collected from adults (average age, 55 years) participating in the UK Biobank Study. They also collected information about the participants' demographics, lifestyles, and overall health. The researchers used deep learning, a type of machine learning that mimics the way humans learn, to analyze images of the retinas and assign a biological age, which they referred to as “retinal age.” Then they calculated the retinal age gap – the difference between retinal age and chronological age. Having a positive retinal age gap was reflective of an older-appearing retina; having a negative retinal age gap was reflective of a younger-appearing retina. Finally, the researchers looked at links between retinal age gap and all causes of premature death.
They found that their machine learning model accurately predicted retinal age and chronological age to within 3.5 years. For every year of positive retinal age gap difference, the risk of premature death from any cause increased 2 percent. Having positive retinal age gaps greater than three years increased the risk of premature death from specific diseases (other than cardiovascular disease or cancer) by as much as 67 percent. These findings held true even after taking other factors into account, such as body weight, high blood pressure, or smoking.
These findings suggest that retinal age, as predicted via deep learning, is a powerful predictor of biological age and premature death risk. Collecting retinal images is a low-cost, non-invasive procedure that may be beneficial in identifying people at risk for premature disease and death. Learn about other strategies for predicting biological age in our overview article on epigenetic aging clocks.
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Goji berries increase carotenoid density in the eye, but supplements don't. www.sciencedaily.com
Age-related macular degeneration is an eye disease characterized by vision loss in the center of the field of vision. It is one of the leading causes of vision loss in older adults worldwide and is often accompanied by marked losses of autonomy, independence, and quality of life. Findings from a recent study suggest that eating goji berries may prevent or delay age-related macular degeneration.
The macula is the portion of the retina directly behind the pupil. Due to pigmentation from high levels of the antioxidant carotenoids, lutein and zeaxanthin, the macula appears yellow. A diet high in lutein and zeaxanthin from foods such as goji berries, kale, pumpkin, salmon, and eggs increases the density of carotenoids in the macula, protecting the tissue from photodamage. In people with early macular degeneration, increasing the amount of lutein in the eye can improve vision; however, less is known about the disease prevention of high lutein levels in healthy adults.
The authors recruited healthy adults between the ages of 45 and 65 years who did not have signs of macular degeneration, verified by an optometrist. They randomly assigned participants to consume either one ounce of goji berries per day or take a supplement containing six milligrams of lutein and four milligrams of zeaxanthin for 90 days. The researchers measured the intensity of yellow color in the macular, which is a good approximation of the density of lutein and zeaxanthin in the eye. Finally, they also measured the yellow color of the skin on participants' finger tips using a device called a “Veggie Meter,” which has demonstrated accuracy in objectively measuring fruit and vegetable intake.
Over 90 days, participants consuming goji berries significantly increased the density of carotenoids in their eyes compared to their baseline values. The lutein and zeaxanthin supplement did not increase carotenoid deposition in the eyes. Participants consuming goji berries had a significant increase in the yellow hue of their skin after just 45 days of consumption, while there was no change for participants taking the carotenoid supplement.
These results support the consumption of goji berries as a strategy for increasing carotenoid density in the eye in healthy adults, which may reduce the risk of age-related macular degeneration.
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Morning exposure to red light improves eyesight in older adults. www.sciencedaily.com
Aging, the collective physiological, functional, and mental changes that accrue in a biological organism over time, affects different organs and organ systems at different rates. The effects of aging on the eyes begins around the age of 40 years, when retinal cells called rods and cones undergo rapid decline due to mitochondrial dysfunction and loss, markedly impairing eyesight. Findings from a recent study suggest that a single exposure to red light in the morning improves eyesight.
Mitochondria have specific light absorbance characteristics that modulate their performance. For example, the mitochondrial electron transport chain is photosensitive to certain wavelengths of light. As a result, exposure to longer wavelengths, such as those in the 650 to 1000 nanometer range, improve mitochondrial function and enhance ATP production. Red light has the longest wavelengths on the visible spectrum, and previous research indicates that exposure to red light restores mitochondrial function in the eyes of older adults.
The current study involved 20 adults between the ages of 34 and 70 years who had no eye disease. The participants looked at a red light (670 nanometers) with their dominant eye in the morning (between 8 a.m. and 9 a.m.) or afternoon (between noon and 1 p.m.) for three minutes. The authors of the study assessed the participants' rod and cone sensitivity before the single-session intervention and again at three hours and one week post-intervention.
They found that after the age of 40 years the participants' rod and cone performance underwent marked decline. These declines were rescued by exposure to red light, but only when the exposure occurred in the morning. Color sensitivity, a feature of the cone cells, improved by up to 20 percent in older participants.
These findings suggest that simple light therapies show promise as strategies to ameliorate vision loss in older adults. Interestingly, sulforaphane, a bioactive compound derived from some cruciferous vegetables, helps protect retinal cells against oxidative stress – a driver of mitochondrial dysfunction. Learn more about sulforaphane in this episode featuring Dr. Jed Fahey.
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Higher caffeine consumption increases glaucoma risk in genetically susceptible people. www.mountsinai.org
Consuming caffeinated beverages such as tea and coffee is a common practice in many cultures around the world. While tea and coffee contain beneficial plant compounds such as antioxidants that lower the risk of disease, the caffeine in tea and coffee increases blood pressure, which may contribute to hypertension-related diseases such as chronic kidney disease, stroke, and glaucoma. Findings of a recent report detail the relationship between caffeine consumption and glaucoma risk.
In glaucoma, the pressure of fluid inside the eye (called intraocular pressure) increases, damaging the optic nerve at the back of the eye. Over time, as damage to the optic nerve accumulates, the risk of vision loss increases. While previous research investigating acute caffeine intake has demonstrated an increase in intraocular pressure following caffeine conumption, research on chronic caffeine consumption has found no relationship between caffeine intake and glaucoma risk. The risk of habitual caffeine consumption may depend on genetics, as other research has found a positive relationship between habitual caffeine intake and glaucoma in those with genetic susceptibility.
The authors conducted a genome-wide association study, a type of study in which researchers look for associations between gene variations called single-nucleotide polymorphisms and disease prevalence. The authors collected genetic data, clinical data measuring intraocular eye pressure, and self-reported dietary data regarding coffee and tea consumption from more than 100,000 participants enrolled in the United Kingdom Biobank study. Next, the authors calculated each participant’s polygenic risk score, which estimates an individual’s genetic susceptibility to a specific disease. Finally, the authors performed a Mendelian randomization analysis, which measures variation in specific genes in order to examine the cause and effect relationship between environmental factors (coffee consumption and total caffeine intake) and disease (glaucoma) risk.
The data revealed that greater total caffeine intake was associated with lower intraocular pressure, but the relationship was not statistically significant. Participants consuming the most caffeine (232 milligrams of caffeine per day or more, the amount in 20 ounces of coffee) had a reduction in intraocular pressure of 0.10 millimeters of mercury (the unit used for blood and eye pressure) compared to participants with the lowest caffeine intake (less than 87 milligrams per day, the amount in one 8-ounce cup of coffee).
Among participants with a high polygenic risk score for glaucoma, however, consuming greater amounts of caffeine (more than 480 milligrams per day, the amount in 42 ounces of coffee) was significantly associated with an increase in intraocular pressure of 0.35 millimeters of mercury compared to participants consuming the least caffeine (less than 80 milligrams per day, the amount in 7 ounces of coffee). While the authors found no overall relationship between caffeine intake and glaucoma, participants with high polygenic risk scores consuming 321 milligrams of caffeine per day or more were four times more likely to develop glaucoma.
The authors concluded that they found no relationship between caffeine consumption and glaucoma risk in the general population. However, their analyses revealed a significant relationship between higher caffeine consumption and increased risk of high intraocular pressure and glaucoma incidence in those with the highest genetic susceptibility for the disease.
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Lutein and zeaxanthin supplementation improves visual processing in younger healthy adults. journals.plos.org
Cognitive function, including complex executive functions like working memory and basic functions like sensory processing, progressively declines with age. While executive function loss is highly variable and easily measurable in older adult populations, younger adults usually perform at a level consistent with their peers, which makes studying cognitive decline in younger adults difficult. In a 2014 report, researchers measured visual processing ability in young adults before and after supplementation with lutein and zeaxanthin.
Visual processing refers to the brain’s ability to utilize and interpret visual information. Because visual processing utilizes similar brain architecture as more complex tasks such as working memory, it is a useful measure in assessing brain health and cognitive decline.
Lutein and zeaxanthin are carotenoid pigments found in foods that accumulate in the retina and throughout the brain and perform light-absorbing, antioxidant, and anti-inflammatory functions. Animal research has demonstrated that the density of these pigments in the eye is a good indicator of their density in the brain, providing researchers a non-invasive means to measure the relationship between pigmentation and cognitive function. Higher pigment density in the eye[has been associated with better cognitive performance and visual processing speed in older adults with or without cognitive decline.
Researchers measured the baseline visual processing speed and retinal concentration of lutein and zeaxanthin in healthy young adults (average age, 22 years). They assigned participants to consume either placebo, zeaxanthin only (20 milligrams), or a combination of zeaxanthin (26 milligrams), lutein (8 milligrams), and mixed omega-3 fatty acids (190 milligrams) per day for four months. They measured retina pigmentation and visual processing speed again following the intervention.
The authors reported a moderate, yet statistically significant, relationship between baseline retinal pigment levels and visual processing speed. Following the intervention, both supplement groups demonstrated a significant increase in retinal pigmentation compared to placebo. Finally, participants in the supplement groups also performed 12 percent better on the critical flicker fusion test and decreased visual motor reaction time by 10 percent, two measures of visual processing.
The authors conclude that lutein and zeaxanthin supplementation may be an effective way to increase visual processing speed, even in young healthy adults.
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Exposure to red light improves vision in adults over the age of 40 years. www.sciencedaily.com
Mitochondria play critical roles in cellular energy and function. The decline in mitochondrial quality and activity that occurs with aging is linked to the development of a wide range of age-related diseases. The highest concentrations of mitochondria in the body are found in the rods and cones of the eyes, where they support multiple aspects of vision. Findings from a new study indicate that viewing a red light restores mitochondrial function in the eyes of older adults.
Mitochondria have specific light absorbance characteristics that modulate their performance. For example, the mitochondrial electron transport chain is photosensitive to certain wavelengths of light. As a result, exposure to longer wavelengths, such as those in the 650- to 1,000-nanometer range, improve mitochondrial function and enhance ATP production. Red light has the longest wavelengths on the visible spectrum.
The intervention study involved 24 adults between the ages of 28 and 72 years who had no eye disease. The participants were instructed to look at a red light with their dominant eye every morning for three minutes every day for two weeks. The authors of the study assessed the participants' rod and cone sensitivity before and after the intervention.
The authors of the study noted that the participants' rod and cone performance declined considerably after the age of 40. However, exposure to red light (670 nanometers) improved both rod and cone function in the participants over the age of 40. The participants' ability to detect colors – a function of cone sensitivity – improved by up to 20 percent in some participants. These findings suggest that simple light therapies show promise as a means to ameliorate visual loss in older adults. Larger studies are needed to confirm these findings.
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BDNF from aerobic exercise may reduce loss of photoreceptor cells in macular degeneration: exercise reduced cell death by 50% in animal model www.sciencedaily.com
From the article:
In the current study, the scientists trained mice to run on a treadmill for one hour per day, five days per week, for two weeks. After the animals were exposed to toxic bright light – a commonly used model of retinal degeneration – they exercised for two more weeks. The exercised animals lost only half the number of photoreceptor cells as animals that spent the equivalent amount of time on a stationary treadmill.
Additionally, the retinal cells of exercised mice were more responsive to light and had higher levels of a growth- and health-promoting protein called brain-derived neurotrophic factor (BDNF), which previous studies have linked to the beneficial effects of exercise. When the scientists blocked the receptors for BDNF in the exercised mice, they discovered that retinal function in the exercised mice was as poor as in the inactive mice, effectively eliminating the protective effects of the aerobic exercise.
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From the article:
Lunghi and Sale put 20 adults through this test twice; in one deprivation test, participants with one eye patched watched a movie while relaxing in a chair. In the other test, participants with one eye patched exercised on a stationary bike for ten-minute intervals during the movie. The results were clear: brain plasticity was enhanced by the exercise.
“We found that if, during the two hours of eye patching, the subject intermittently cycles, the perceptual effect of eye patching on binocular rivalry is stronger compared to a condition in which, during the two hours of patching, the subject watches a movie while sitting on a chair. That is, after physical activity, the eye that was patched is strongly potentiated, indicating increased levels of brain plasticity.”