Low Vitamin D Might Be Risk Factor for Glaucoma
April 2014 Low blood levels of vitamin D could increase your risk of glaucoma, according to a new study.
In research published this month in Public Health Nutrition, investigators examined the relationship between five categories of serum vitamin D levels and the prevalence of open-angle glaucoma among 6,094 adults in South Korea.
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The odds ratio of having glaucoma among study participants comprising the group with the lowest vitamin D levels was significantly higher than that for those with more robust vitamin D levels.
The researchers also found that predictors for worsening of open-angle glaucoma such as high eye pressure and changes in appearance of the optic nerve had a significant relationship with low serum vitamin D levels.
The study authors concluded that vitamin D deficiency should be considered a potential risk factor for the development of open-angle glaucoma.
Likelihood of Blindness From Glaucoma Has Dropped by Nearly Half
January 2014 The probability of blindness due to the serious eye disease glaucoma has decreased by nearly half since 1980, according to a study conducted by the Mayo Clinic. The study was the first to assess long-term changes in the risk of progression to blindness and the population incidence of glaucoma-related blindness.
"Puff tests" and other testing for glaucoma have become almost routine during eye exams. Early detection of the disease helps explain why the probability of blindness has decreased, at least in some areas.
Researchers analyzed the medical records of all the people 40 and older in Olmsted County, Minn., who were diagnosed with the eye disease between 1981 and 2000. They compared these people with patients diagnosed with glaucoma between 1965 and 1980.
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The incidence of glaucoma did not change, but the risk of going blind in at least one eye fell from about 26 percent in the earlier group to less than 14 percent in the newer group. The researchers also found that the annual incidence of glaucoma-caused blindness dropped by more than half.
Advances in diagnosis and therapy are likely causes for the decrease, according to researchers. But they caution that a significant proportion of glaucoma patients still progress to blindness. Glaucoma is a leading cause of irreversible blindness worldwide and affects more than 2.7 million individuals aged 40 and older in the United States and 60.5 million people globally.
Contacts That Deliver Glaucoma Medication May Soon Be a Reality
December 2013 Contact lenses that deliver glaucoma medication over long periods are getting closer to reality, say researchers at the Massachusetts Eye and Ear Infirmary.
In their study, the lenses delivered the glaucoma drug latanoprost (brand name Xalatan) continuously to laboratory animals for a month. The goal, researchers said, is to someday have these lenses replace eye drops now used to treat the eye disease. Glaucoma is the leading cause of irreversible blindness worldwide.
The lenses, which appeared safe in cell culture and animal studies, are the first to be shown to release drugs for this long in animals, according to the researchers. The study will appear online and in the January print issue of the journal Biomaterials.
The lens the research team developed is capable of delivering large amounts of drug at substantially constant rates over weeks to months, according to researchers at the Laboratory for Biomaterials and Drug Delivery at Boston Children's Hospital. They believe a non-invasive method of sustained eye drug delivery could save millions of people from blindness if it helps them comply with their medication regimen.
Connection Found Between Glaucoma and Sleep Apnea
November 2013 Sleep apnea is an independent risk factor for open-angle glaucoma, says new research from Taipei Medical University.
This obstructive sleep apnea sufferer is using a CPAP (continuous positive airway pressure) machine to keep his airway open during sleep.
The retrospective study took information from data collected across the population and found that those who had been diagnosed with sleep apnea were 1.67 times more likely to have open-angle glaucoma in the five years after diagnosis than those without the sleep condition.
Glaucoma affects nearly 60 million people worldwide and is the second-leading cause of blindness. If left untreated, glaucoma reduces peripheral vision and eventually may cause blindness by damaging the optic nerve.
According to the World Health Organization, sleep apnea is a chronic condition that blocks breathing during sleep for more than 100 million people worldwide.
In obstructive sleep apnea, the airway becomes blocked, causing breathing to stop for up to two minutes. Symptoms include loud snoring, gasping or choking while asleep, morning headaches and persistent daytime sleepiness.
Widespread Brain Changes Found in Glaucoma Patients
July 2013 Glaucoma traditionally has been defined as damage to the optic nerve (usually caused by high eye pressure) that results in visual field loss. A new study offers evidence that glaucoma may instead be a neurological disorder with wider implications.
MRIs revealed differences in brain structures of people with glaucoma vs. people without the disease.
Researchers at Wills Eye Institute in Philadelphia have discovered widespread structural changes in the brains of glaucoma patients. They looked at MRIs of brain structures of 15 people with glaucoma of varying severity and 15 without glaucoma, matched for age, race and sex. None of the participants had any known neurological or other disorders that could affect the visual field, and all passed a mental health screening.
The MRI scans were analyzed to measure the volumes of 93 brain structures and to identify structures that differed significantly between the glaucoma group and the control group. Also, the volumes of all brain structures in the glaucoma group were correlated with the severity of the patients' glaucoma.
Five brain structures differed significantly between the two groups, all of which are involved in visual processing: the right and left inferior occipital gyri, the right middle occipital gyrus, the right inferior temporal gyrus, and the right occipital lobe white matter. Surprisingly, all of these structures were larger in the glaucoma group than in the control group.
Within the glaucoma group, 38 percent of all brain structures showed a link between decreased volume and glaucoma severity.
These results suggest patients with glaucoma "undergo widespread and complex changes in cortical brain structure and that the extent of these changes correlates with disease severity," according to the study authors.
The study report appeared online this month in the journal Investigative Ophthalmology & Visual Science.
Twice as Many Collisions Possible for Drivers With Advanced Glaucoma
November 2012 In a recent driving simulation, people with advanced glaucoma had twice as many accidents as those with normal vision.
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The study, conducted at Tohoku University Graduate School of Medicine in Sendai, Japan, matched two 36-person groups for age, driving experience and more.
The most common type of accident for both was a collision with a child, car or other object that entered the scene suddenly from the side. But the drivers with glaucoma had more than twice as many collisions as the normal-vision drivers.
The problem is that glaucoma can reduce peripheral vision, whether partially or severely, without harming central vision. People with advanced glaucoma often pass the visual acuity test given in most countries and in most of the United States, because it checks only straight-ahead distance vision.
A visual fields test could prevent those with severe peripheral vision loss from renewing their license. Or it could trigger a requirement for special mirrors to be installed on their vehicles, to help them overcome their side vision loss.
Results of this study were reported this month at the annual meeting of the American Academy of Ophthalmology.
Taking Statins? You May Be Less Likely to Develop Glaucoma
October 2012 Since so many people take statins to lower their risk for cardiovascular disease, much research has been done recently to determine their effect on the body overall, including the eyes.
Now a study of more than 300,000 people aged 60 and older concludes that those with high blood levels of unhealthy fats who took statins continuously for two years saw their risk for open-angle glaucoma reduced by 8 percent, compared with those who did not take statins.
Statin use may protect the optic nerve and retinal nerve fibers, which are harmed by glaucoma. Since the statins seem to reduce glaucoma risk most before it is diagnosed or in the early stages of the disease, the research may lead to new preventive treatment.
"Statins' apparent ability to reduce glaucoma risk may be due to several factors, including improved blood flow to the optic nerve and retinal nerve cells and enhanced outflow of the aqueous fluid, which may reduce intraocular pressure," said Joshua Stein, MD, MS, who led the study. "While more research is needed, we hope our results may contribute to saving the sight of thousands who are predisposed to glaucoma."
iStent Now Available in U.S. To Reduce Eye Pressure After Implantation During Cataract Surgery
LAGUNA HILLS, Calif., June 2012 The FDA has approved the iStent Trabecular Micro-Bypass Stent System, made by Glaukos Corp., for use during cataract surgery.
The titanium device, which resembles a bent pipe or periscope, is approved to treat mild or moderate open-angle glaucoma in people who are already using medication to reduce high eye pressure. It is placed through the meshwork of tissue at the outer edge of the iris, into a canal that drains the fluid from the eye, thereby reducing eye pressure.
In a study, 240 eyes received the iStent, and a year later 68 percent had the study target pressure of 21mm of mercury or lower without the use of medication to lower eye pressure, compared with 50 percent who had cataract surgery alone.
iStent complications included unsuccessful or difficulty implanting, poor positioning of the stent, the stent touching the iris or cornea during surgery, being dropped into the eye prior to implantation, and becoming blocked after surgery.
Phone Reminders Fail To Keep Glaucoma Patients on Meds
PHILADELPHIA, June 2012 If someone called to remind you to take your glaucoma medication, would it help you to stay on your treatment schedule?
That's the idea tested by a recent study at the University of Pennsylvania of 312 glaucoma patients who were considered noncompliant because they didn't take their medication, refill their prescriptions and/or keep their doctor appointments.
The patients were divided into a treatment group and a control group. The treatment group received automated and interactive phone calls, as well as printed materials tailored to them. The control group received just recommendations for medical appointments and medication refills, considered the usual level of care.
Perhaps surprisingly, the phone calls didn't seem to improve the situation. While both groups showed a statistically significant increase in adherence to their treatment regimens, the treatment group did not show a statistically significant higher level of adherence than the control group.
A report of the study appeared online in June in Archives of Ophthalmology.
Most Glaucoma Patients Are Not Using Their Eye Drops Correctly
DALLAS, April 2012 Eye doctors often bemoan the fact that many people with glaucoma don't use their prescribed medication and lose their vision as a result. But nine out of 10 glaucoma patients who are trying to instill their medicated eye drops don't do it correctly, suggests a recent study.
This is a serious problem, because it may mean insufficient treatment of the sight-stealing disease. Other issues include the waste of money spent on costly medications and contamination of medication bottles.
During the study, 70 glaucoma patients with a mean age of 54 were watched as they used tear substitute drops with the same method they normally used when instilling glaucoma medication eye drops at home.
The researchers measured the time it took to get the first drop into the eye, the number of drops used, where the drops made contact, any contact with the bottle tip and whether the eyelids and tear ducts closed after each drop. Here are the results:
- The time it took to instill the first drop ranged from 8.7 to 23.5 seconds (mean was 14.8).
- The number of drops per instillation ranged from one to eight drops (mean was 1.8).
- The drops fell onto the eyelids or cheek in 22 patients.
- Fifty-three patients touched the tip of the bottle to the eye or eye area.
- Twenty closed their eyes after the drop, and four had their tear ducts close.
- Six patients (about 9 percent) squeezed one drop into the eyelid sac without bottle tip contact, which is the correct way to use glaucoma drops.
The results were similar to those of a previous study on visually impaired glaucoma patients. A report of this study appeared in the March issue of Journal of Glaucoma.
Large Doses of Calcium and Iron Supplements May Increase Glaucoma Risk, Says Study
SAN FRANCISCO, February 2012 Iron and calcium supplementation above a certain level may increase your risk of developing glaucoma, says recent research.
In a cross-sectional study of participants in the 2007-2008 National Health and Nutrition Examination Survey, 3,833 people aged 40 or older were interviewed about their use of dietary supplements and antacids (which usually contain calcium) during the previous 30 days.
Those who took at least 800 mg per day of supplementary calcium or at least 18 mg per day of supplementary iron (both are oxidants) had a greater chance of glaucomatous disease than those not taking these supplements. In fact, taking both iron and calcium above these levels increased the odds of developing glaucoma even more.
For perspective, here are the amounts of iron and calcium found in some popular supplements:
- A two-tablet dose of Tums Ultra Strength 1000 contains 800 mg of calcium, while two tablets of Tums Extra Strength 750 contain 600 mg.
- A one-tablet daily dose of Centrum Silver Women 50+ contains 500 mg of calcium and 8 mg of iron, while the same dose of Centrum Women Under 50 contains the same amount of calcium but 18 mg of iron.
- A two-tablet daily dose of Nature Made Calcium 500 mg with Vitamin D contains 1,000 mg of calcium. Incidentally, this is the recommended daily amount of calcium, according to the label.
- A one-tablet daily dose of Nature Made Iron contains 65 mg of iron.
The researchers noted that further study is needed to decide whether oxidant intake is a definite risk factor for the eye disease.
A report of this study appeared online in January in Investigative Ophthalmology & Visual Science.
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[Page updated April 15, 2014]
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