Perspective Optometry (formerly Vision Source) Vancouver Optometrists Optometrist for kids and adults. Clinic Address: 7633 Nanaimo Street, Vancouver, B.C.; clinic telephone: 604-435-3931.
The AREDS2 results for the average American with a suboptimal daily intake of lutein/zeaxanthin showed a statistically significant prevention of catastrophic vision loss, primarily neovascularization. That was an incredible result, favoring a new AREDS2 formulation minus beta carotene but with lutein plus zeaxanthin.
In the first AREDS trial, participants with AMD who took the AREDS formulation were 25 percent less likely to progress to advanced AMD over the five-year study period, compared with participants who took a placebo. In AREDS2, there was no overall additional benefit from adding omega-3 fatty acids or a 5-to-1 mixture of lutein and zeaxanthin to the formulation. However, the investigators did find some benefits when they analyzed two subgroups of participants: those not given beta-carotene, and those who had very little lutein and zeaxanthin in their diets.
“When we looked at just those participants in the study who took an AREDS formulation with lutein and zeaxanthin but no beta-carotene, their risk of developing advanced AMD over the five years of the study was reduced by about 18 percent, compared with participants who took an AREDS formulation with beta-carotene but no lutein or zeaxanthin,” said Emily Chew, M.D., deputy director of the NEI Division of Epidemiology and Clinical Applications and the NEI deputy clinical director. “Further analysis showed that participants with low dietary intake of lutein and zeaxanthin at the start of the study, but who took an AREDS formulation with lutein and zeaxanthin during the study, were about 25 percent less likely to develop advanced AMD compared with participants with similar dietary intake who did not take lutein and zeaxanthin.”
Because carotenoids can compete with each other for absorption in the body, beta-carotene may have masked the effect of the lutein and zeaxanthin in the overall analysis, Chew said. Indeed, participants who took all three nutrients had lower levels of lutein and zeaxanthin in their blood compared to participants who took lutein and zeaxanthin without beta-carotene Removing beta-carotene from the AREDS formulation did not curb the formulation’s protective effect against developing advanced AMD, an important finding because several studies have linked taking high doses of beta-carotene with a higher risk of lung cancer in smokers. Although smokers were not given a formulation with beta-carotene in AREDS2, the study showed an
association between beta-carotene and risk of lung cancer among former smokers. About half of AREDS2 participants were former smokers. “Removing beta-carotene simplifies things,” said Wai T. Wong, M.D., Ph.D., chief of the NEI Neuron-Glia Interactions in Retinal Disease Unit and a co-author of the report. “We have identified a formulation that should be good for everyone regardless of smoking status,” he said. Adding omega-3 fatty acids or lowering zinc to the AREDS formulation also had no effect on AMD progression.
More than 4,000 people, ages 50 to 85 years, who were at risk for advanced AMD participated in AREDS2 at 82 clinical sites across the country. Eye care professionals assess risk of developing advanced AMD in part by looking for yellow deposits called drusen in the retina. The appearance of small drusen is a normal part of aging, but the presence of larger drusen indicates AMD and a risk of associated vision loss. Over time, the retina begins to break down in areas where large drusen are present during a process called geographic atrophy. AMD can also spur the growth of new blood vessels beneath the retina, which can leak blood and fluid, resulting in sudden vision loss. These two forms of AMD are often referred to as dry AMD and wet AMD respectively.
Can a daily multivitamin alone provide the same vision benefits as an AREDS formulation?
No. The vitamins and minerals tested in the AREDS and AREDS2 trials were provided in much higher doses than what is found in multivitamins. Also, it is important to remember that most of the trial participants took multivitamins. Taking an AREDS formulation clearly provided a benefit over and above multivitamins.
Can diet alone provide the same high levels of antioxidants and zinc as the AREDS formulations?
No. The high levels of vitamins and minerals are difficult to achieve from diet alone. However, previous studies have suggested that people who have diets rich in green, leafy vegetables—a good source of lutein/zeaxanthin—have a lower risk of developing AMD. In the AREDS2 trial, the people who seemed to benefit most from taking lutein/zeaxanthin were those who did not get much of these nutrients in their diet. Within this group, those who received lutein/zeaxanthin supplements had a 26 percent reduced risk of developing advanced AMD compared with those who did not receive the supplements.
In summary, recent research has clearly shown that problems in eye focusing and eye teaming are common in students and should be evaluated, especially in children who are struggling in school. If a problem is found, then effective treatment should be prescribed. Timely identification and treatment of eye focusing and teaming problems can remove a potential obstacle that may restrict a child from performing at his or her full potential.
Dr. Freeman: What are your thoughts on the traumatic brain injury that might be associated with these injuries?
Dr. Beatty: Well, traumatic brain injury was one of the things that kept us busy. A recent review of the VA literature reports that over 250,000 US service people have been diagnosed with some form of traumatic brain injury.2 The symptoms of those patients who have suffered traumatic brain injury are very similar to those associated with migraine headache—visual distortion, headaches, and extreme photosensitivity, not only to sunlight but even to lights inside. Some patients are very sensitive to the flickering of fluorescent lights. These are some visual disturbances that you won’t pick up just by having someone read an eye chart. The symptoms may be episodic, depending on how the patient is recovering from the post-concussive events, which can take quite a while; some may not really ever recover.
Dr. Freeman: How do you think eye care practitioners can best serve these veterans?
Dr. Beatty: I think that, overall, anyone who has been in a combat zone, and especially anybody who has had a concussion or suffered a concussive force by a nearby IED, will need to have very complete eye examinations on an ongoing basis. Dr. Glen Cockerham, at the VA Hospital in Palo Alto, California, did a study of returning veterans3 and, although the number was small, he found that a very high percentage of those veterans had some sort of ocular abnormality that could be attributable to their time in the combat zone. And that’s where we think that there may be problems with late-onset glaucoma as the years go by and as these veterans get older. In summary, very careful and complete eye examinations are necessary, and the emphasis cannot only be on detecting ocular pathology. It is essential to talk with these patients to determine what bothers them about their visual system—for example, do they experience photophobia or double vision? And, then, institute not only medical treatment but nonmedical as well—such as different types of eyewear that have tints, prism; low-vision devices that address the visual impairment; non-optical aids that can help with the distortion. In addition, there may be some need for different types of visual training. There should be attention to visual field analysis, detecting areas where there may be scotomas or blind spots.The US army uses doctors of optometry to provide vision therapy to soldiers who have sustained brain injuries. Here is a video:
And all of these things may be complicated by the fact that these patients also have cognition problems, deficits of short-term and long-term memory, which impacts their ability to handle low vision devices. Some of them have lost limbs or have other limitations that make it difficult to hold things and that complicate their visual rehabilitation. We’re now saving people on the battlefield with brain injuries and other types of trauma who, in the past, did not make it back to the trauma centers, and they are surviving and undergoing rehabilitation. This will result in more challenging long-term rehabilitative care, which is going to involve extensive physical and occupational therapy. And, in addition to those therapies, there should be visual rehabilitation.
Myopia is quickly reaching epidemic proportions world wide:
Numerous scientific studies have also documented the presence of eye movement anomalies and deficits of perception of low contrast, low spatial frequency, and high frequency temporal visual information in dyslexics. Anomalies of visual attention with short visual attention spans have also been demonstrated in a large number of cases. Spatial orientation is also affected in dyslexics who manifest a preference for spatial attention to the right. This asymmetry may be so pronounced that it leads to a veritable neglect of space on the left side.
This research indicates there are significant associations between reading speed, refractive error, and in particular vergence facility. It appears sensible that students being considered for reading specific IEP status should have a full eye examination (including cycloplegia), in addition to a comprehensive binocular vision evaluation.
