Viibryd And Cataracts
Eye Drops To Prevent Cataracts
Eye Drops For Cataracts?
An old eye drop maybe making a new comeback. Pirenoxine, also known as Catalin in Japan, was the subject of a recent study in China. [1] The study tested the ability of Pirenoxine (PRX) to inhibit cataract formation in test tubes. The test tubes contained crystallins, a protein found in the lens inside the human eye. PRX appears to act by binding calcium and selenite ions. Both of these ions have been shown to contribute to cataract formation in the cortex (inner layer of the lens) when they are elevated. They act to increase the breakdown of the crystallins protein structure. By binding these ions the rate of of cataract formation in the test tubes was decreased by 38%.
Cataract Prevention Eye Drops In Use Since 1958
These eye drops have been used by eye doctors in Japan since 1958. A study in 2006 questioned why Japanese eye doctors are prescribing Catlin since there was no significant supporting evidence.[2] It has been thought to be a placebo type of treatment that has been widely adopted. Numerous companies have manufactured pirenoxine overseas under a variety of trade names. Both Allergan and Alcon have made versions of pirenoxine. Takeda is a large phamaceutical company in a number of other countries. Santen, Ferron, and Farmigea all produce a brand. Clarvisan, Clarvisor, and Baineiting are some of the different brands that can be found around the world. There is no FDA approved eye drop in the United States at this time.
Problems With Cataract Prevention Eye Drops
There are several potential problems with the PRX eye drop medications. Research has not yet shown any effectiveness for treating or preventing cataracts in the living eye. Another significant issue lies in the solution used to deliver the drops to the eyes. Thimerosal is used as a preservative in common preparations of this eye medication. Thimerosal is a derivative of mercury, and has a fairly high rate of allergic reactions. It also is mildly toxic to the cornea tissue of the eye, and may cause undesirable long term changes when used on a chronic basis.
We should see more research in the future that addresses both of the problems above. Hopefully we will have a new treatment for cataracts not too far down the line.
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Inorg.Chem. 2011, 50 (1), pp 365–377
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Sekimoto M, Imanaka Y, Kitano N, et al. Why are physicians not persuaded by scientific evidence? A grounded theory interview study. BMC Health Serv Res 2006 Jul 27; 6:92
Optometric Nutrition Society-Diet and Eye Health
The Optometric Nutrition Society
A Professional Society Whose Time Has Come
Dr.David Kisling of Fort Collins,Colorado has become an active member of The Optometric Nutrition Society. Lifestyle modification and nutrient intake are proving to play an important role in vision health and eye disease prevention. Several studies have shown a correlation with nutrition and chronic eye disease. This area of study has become a focus of primary vision care doctors.
The purpose of the Optometric Nutrition Society is to:
To promote excellence in the care of optometric patients through nutritional support of eye health and the prevention and control of ocular and systemic disease.
To sponsor professional symposia as well as a website, and to generate materials to educate professionals regarding the role of nutrition in systemic and ocular health.
To provide a collegial atmosphere where health care professionals can exchange ideas and concepts regarding nutritional influences on vision.
Provide a resource pool of clinically relevant refereed studies that support the role of safe nutritional support for the management of ocular and systemic disease.
To monitor and validate claims made by industry regarding the quality and efficacy of nutritional supplements.
To encourage the inclusion of nutrition education in the curricula of optometry schools.
The society closely monitors peer-reviewed published science on nutritional influence on eye health, as well as safety and ethical issues regarding specific micronutrients included in supplements being marketed to vision patients.
For more information contact:
Name: Dr David Kisling, O.D.
Address 181 West Boardwalk Ste. 201
Fort Collins,CO. 80525
Phone: (970) 226-0959
Email info@harmonyeyes.net
Childrens Eyes Need UV Protection to Prevent Blinddness
Do your child a favor when they visit their optometrist for back to school eye exam this year. Discuss sunwear protection with the eye doctor. Lifetime doses of UV radiation from the sun are associated with nuclear sclerosis. This is a type of cataract where the lens yellows then turns brown similar to plastic left outdoors for a few years. UV exposure has also been implicated as a risk factor for macular degeneration, and recent studies suggest even visible blue light may be damaging.
If you live in an area like Fort Collins at high altitude and snow, closer to the equator, or spend time around lakes or the ocean, your child’s exposure rate is much higher.
Think of sun protection for the eyes just like sun protection for the skin. No reputable childcare center allows children on outdoor excursions without sunscreen. It should be the same for your child’s eyes. UV (Ultraviolet) protection with sunwear that is tinted or transitions lenses that are clear indoors and darken outdoors are both good options. If you child spends a large amount of time in outdoor activities consider sunglasses that wrap around on the side. If you Normal eye glasses may allow 35% of the light in from the side. Gray is the tint that alters color perception the least but brown is popular also.
For non prescription sun wear avoid the cheap $5.00 variety. Look for something with an 100% UV protection. Expect to pay $30 to $40 at minimum for the quality your child deserves. Poor quality sunwear may actually damage your child’s eyes by dilating them and allowing more UV exposure with inadequate protection.
By starting early you are providing preventative care for two of the leading causes of blindness.
Cataract Prevention at NASA
NASA and the National Eye Institute have been working together to develop a non-invasive method to measure very early development of cataracts and monitor any progression. This is important to astronauts receiving higher daily dose of radiation, especially on a long mission such as the future Mars flight, but there are great potential applications for preventing and treating cataracts in the future. The crystalline lens in the eye is composed largely of water but there is a class of proteins present known as alpha-crystallins.
The amount of Alpha-crystallin Proteins in the eye are largely fixed at birth, we don’t produce more. They function to a help the lens maintain it’s refractive index, which allows it to focus light on the retina so we can clearly see images. They also act as so called chaperone’s, dating the bad proteins that breakdown in the lens from oxidative stress. By joining up with theses proteins they prevent cross linking between large numbers of damaged proteins and other damaged cellular substances that can develop into large clumps and form opacities in the lens. These capacities can develop large enough in size that they start to interfere with your eyesight and become clinically referred to as cataracts.
The new instrument measures how much Alpha-crystallin Proteins scatter light and can detect their levels and changes over time. Now the potential exists to measure changes in response to environmental factors.
We have shown that this non-invasive technology that was developed for the space program can now be used to look at the early signs of protein damage due to oxidative stress, a key process involved in many medical conditions, including age-related cataract and diabetes, as well as neurodegenerative diseases such as Alzheimer’s and Parkinson’s," said NASA’s Dr. Ansari. "By understanding the role of protein changes in cataract formation, we can use the lens not just to look at eye disease, but also as a window into the whole body."
Oxidative Stress is caused by an imbalance between the production of Reactive oxygen species and your bodies capaictiy to neutrlaize them, the reactive intermediates, and repair any resultant cellular damage. Oxidative stress results from UV, radiation, drugs, chemicals,smoking, dietary components and other environmental factors that create oxygen is states where free electrons readily bind to cellular substances, Free radicals are atoms, molecules, or ions with unpaired electrons that also readily bind to proteins, lipids, and the DNA of our cells. When the threshold of repair is passed, and the Alpha-crystallin Proteins become lowered with age to the point where they can’t adequately act as chaperone’s to prevent these damgaed proteins from aggreagting into the clumps, you will likley develop cataracts.
Hopefully we can start to clarify some of the lingering questions and move forward into the arean of cataract prevention and reversal. Antioxidants have held out great hope for cataract prevention and anti-aging in general, but questions have been raised in some recent studies about the capacity of antioxidants to help.There is even a small school of thought that believes low doses of oxidative stress is essential in prolonging life. At this point, the only certainly is Vitamin A is contraindicated in smokers.
I still strongly believe in the value of antioxidants in a preventative role. Some studies have shown lutein and zeathin have reduced the incidence of cataract formation. Extensive studies are underway to test their role in treating macular degeneration. Vitamin C is still on my list as anti-catarogenic. One factor to keep in mind is natural is not always good. St John’s Wort does have some properties that my causes cataracts and sunglasses need to be worn and sunlight limited if you are taking St Johns Wort (commonly used for depression). This does not appear to be a strong causative factor but one to consider and compensate for when working in the sun.
Other lifestyle factors such as smoking, obesity, and eating a high glycemic index (highly refined high sugar,highly refined foods) are controllable risk factors. While I have not see the reasons published, presumably oxidative stress is the common factor. Smoking is know ot decrease antioxidants systemically in your body, the cellular damage from free radicals is obvious in the loss of skin elasticity. Even visible blue light causes oxidative damage in the retina and probably in the lens, Lutien and xeanthin may act as antioxidants in the lens to help prevent cataract development.
We can look forward to a great future in early detection (prior to visible damages) from cataracts and determining what lifestyle, dietary,and potential drugs ans supplements may prevent cataracts at some point in the future.
For now diet,exercise, a healthy body weight, a daily supplement (without the Vitamin A for smokers, added Lutien, Zeanthin, and vitamin C is probably your best bet. And everything you can get from food (such as Lutein from spinach or other foods with high levels is presumably better than a pill.—Add protect your eyes from the UV sunlight with quality sunglasses or UV blocking contact lenses.
The next time you see your Eye Doctor they may just be measuring your alpha-crystallins levels, especially if you signed up for that 3 year cruise to Mars.
Our office is a Proud Participent in Vision Service Plan, and we work with you to maximize your understanding of your vision insurance plans benefits. It is one more way of thankng you for entrusting your eye axam and vision care with us.
Out of This World Eyecare
Fascinating information from out for this world on new directions in eyecare from the NEI:
NEI Press Release
NATIONAL INSTITUTES OF HEALTH
National Eye Institute
For Immediate Release Thursday, January 8, 2009
From Outer Space to the Eye Clinic: New Cataract Early Detection Technique
Patients and Astronauts Benefit from NEI-NASA Collaboration
A compact fiber-optic probe developed for the space program has now proven valuable for patients in the clinic as the first non-invasive early detection device for cataracts, the leading cause of vision loss worldwide.
Researchers from the National Eye Institute (NEI), part of the National Institutes of Health, and the National Aeronautics and Space Administration (NASA) collaborated to develop a simple, safe eye test for measuring a protein related to cataract formation. If subtle protein changes can be detected before a cataract develops, people may be able to reduce their cataract risk by making simple lifestyle changes, such as decreasing sun exposure, quitting smoking, stopping certain medications and controlling diabetes.
“By the time the eye’s lens appears cloudy from a cataract, it is too late to reverse or medically treat this process,” said Manuel B. Datiles III, M.D., NEI medical officer and lead author of the clinical study. “This technology can detect the earliest damage to lens proteins, triggering an early warning for cataract formation and blindness.”
The new device is based on a laser light technique called dynamic light scattering (DLS). It was initially developed to analyze the growth of protein crystals in a zero-gravity space environment. NASA’s Rafat R. Ansari, Ph.D., senior scientist at the John H. Glenn Research Center and co-author of the study, brought the technology’s possible clinical applications to the attention of NEI vision researchers when he learned that his father’s cataracts were caused by changes in lens proteins.
Several proteins are involved in cataract formation, but one known as alpha-crystallin serves as the eye’s own anti-cataract molecule. Alpha-crystallin binds to other proteins when they become damaged, thus preventing them from bunching together to form a cataract. However, humans are born with a fixed amount of alpha-crystallin, so if the supply becomes depleted due to radiation exposure, smoking, diabetes or other causes, a cataract can result.
“We have shown that this non-invasive technology that was developed for the space program can now be used to look at the early signs of protein damage due to oxidative stress, a key process involved in many medical conditions, including age-related cataract and diabetes, as well as neurodegenerative diseases such as Alzheimer’s and Parkinson’s,” said NASA’s Dr. Ansari. “By understanding the role of protein changes in cataract formation, we can use the lens not just to look at eye disease, but also as a window into the whole body.”
The recent NEI-NASA clinical trial, reported in the December 2008 Archives of Ophthalmology, looked at 380 eyes of people aged 7 to 86 who had lenses ranging from clear to severe cloudiness from cataract. Researchers used the DLS device to shine a low-power laser light through the lenses. They had previously determined alpha-crystallin’s light-scattering ability, which was then used to detect and measure the amount of alpha-crystallin in the lenses.
They found that as cloudiness increased, alpha-crystallin in the lenses decreased. Alpha-crystallin amounts also decreased as the participants’ ages increased, even when the lenses were still transparent. These age-related, pre-cataract changes would remain undetected by currently available imaging tools.
“This research is a prime example of two government agencies sharing scientific information for the benefit of the American people,” said NEI director Paul A. Sieving, M.D., Ph.D. “At an individual level, this device could be used to study the effectiveness of anti-cataract therapies or the tendency of certain medications to cause cataract formation.”
The DLS technique will now assist vision scientists in looking at long-term lens changes due to aging, smoking, diabetes, LASIK surgery, eye drops for treating glaucoma, and surgical removal of the vitreous gel within the eye, a procedure known to cause cataracts within six months to one year. It may also help in the early diagnosis of Alzheimer’s disease, in which an abnormal protein may be found in the lens. In addition, NASA researchers will continue to use the device to look at the impact of long-term space travel on the visual system.
“During a three year mission to Mars, astronauts will experience increased exposure to space radiation that can cause cataracts and other problems,” Dr. Ansari explained. “In the absence of proper countermeasures, this may pose a risk for NASA. This technology could help us understand the mechanism for cataract formation so we can work to develop effective countermeasures to mitigate the risk and prevent it in astronauts.”
Macular Degeneration and Vitamin D-Update
Melanocytes are specialized cells that contain the pigment found in our hair skin, eyes, and other area of the body. The eye has melanocytes in the iris, retina, and the choroidal layer under the retina that supplies it with blood. Underneath the retina is a layer of cells referred to as the retinal pigmented epithelium. These cells interact with the photoreceptor cells, the rods and cones that register light you see and turn it into electrical impulses. Melanin is the pigment and it comes in two different forms. In the retina, melanin acts as an antioxidant to help protect the tissue from free radicals that can damage the cellular DNA.
Various detrimental influences can reduce this protective function and may even cause it to accelerate damage from free radicals. Ultraviolet exposure, blue visible light, and high levels of oxidative stress can cause cell damage and increase the rate of cell death. An article by Meyskens FL, Farmer P, Fruehauf JP suggested that this may be a contributory factor in macular degeneration and choroidal melanomas.
Melanocytes also populate our skin where they protect the underlying levels from ultraviolet damage. UV-B exposure is an essential step in producing the active form of vitamin D. Darker skinned intervals have more UV screening and subsequently are more at risk for low levels of vitamin D. When you wear highly protective sunscreen the same effect occurs, lower levels of UV are absorbed by the skin and the proactive form of Vitamin D does not get its needed UV-B exposure to form. It is a very narrow band of UV-B that is needed, not the entire spectrum.
Vitamin D degeneration is related to multiple forms of cancer and other health problems. Macular degeneration may have an association with lowered vitamin D. One possibility is the overall reduction in UVB on the skin from sunscreen, living indoors, and poor dietary habits results in systemic changes in vitamin D levels that precipitates cellular changes in the retina unrelated to the melanin in the eye. Another possibility is lowered systemic levels of vitamin D resulting in decreased melanin production in the retina. This could lead to an overload to the pigmented epithelial cells from oxidative stress and UV exposure inside the eye, degrading the functional capacity of the melanin to protect the retina.
The irony is UV exposure is a risk factor for cataracts and macular degeneration and we are always encouraging eye protection against UV (and rightfully so given today’s evidence). With the known association of skin cancer and UV exposure it is not prudent to drop recommendation for sunscreen and limiting sun exposure.
At some point there will be better answers. For now, some mild daily exposure to UV with eyewear that includes UV protection is something you should discuss with your eye doctor and dermatologist or family physician. Vitamin D supplementation during winter months and in geographic locations that get limited sunlight should also be considered with your healthcare providers. Perhaps sunscreen lotions will be developed that allow the narrow band of UV-B needed to pass through in the future. Many people have vision insurance coverage like Vision Service Plan that provides coverage for eyeglasses. Even if your prescription is minor, having protection against UV and visible blue light is good preventative medicine if you spend time outdoors. And if you spend six months on a submarine or live underground you should examine your options-and maybe see a psychologist!
Reference:
Meyskens FL, Farmer P, Fruehauf JP (June 2001). “Redox regulation in human melanocytes and melanoma”. Pigment cell research / sponsored by the European Society for Pigment Cell Research and the International Pigment Cell Society 14 (3): 148-54. doi:10.1034/j.1600-0749.2001.140303.x. PMID 11434561.




