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Ophthalmology and Optometry
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New Technique Developed Reduces Halo Effect Caused by Lenses PDF
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Ophthalmology and Optometry
Monday, 20 April 2015

Halo Effect LensesIn a recent study published in Optics Communications, scientists from Bar-Ilan University in Israel have presented a new technique that significantly reduces the halo effect that is generated when using multifocal (contact and intra-ocular) lenses and looking at bright point sources in dark conditions.

Presbyopia is a result of natural aging and stems from a gradual thickening and decrease in elasticity of the lens inside the eye. Corrective lenses used to address presbyopia often lead to a halo effect. This is basically a glow or color light pattern observed when looking at a bright source of light in front of a dark background. It is mostly experienced at night when people see halos around street lamps and car headlights, and it can make driving at night unsafe or even impossible in extreme cases.

Co-author of the paper, Prof. Zeev Zalevsky, head of the Electro-Optics study program of the Faculty of Engineering at Bar-Ilan, explains, "Our solution involves smoothening the surface structure of a contact lens or an intra-ocular lens that has extended depth of focus or multifocal capabilities. The smoothening does not complicate the fabrication complexity of the lens and yet yields the same optical performance in treating presbyopia and assisting people after cataract surgery, but with about one order of magnitude smaller. This allows people that use such lenses to be able to use them also at night."

More and more commercial ophthalmic products incorporate EDOF (extended depth of focus) and multifocal technologies in contact and intra-ocular lenses to solve presbyopia. Until now, such lenses were very problematic when used in dark illumination conditions. The researchers say their proposed concept can resolve the above difficulties and make the existing products even more applicable and useful.

 
Stem Cell Injection Soon To Reverse AMD PDF
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Ophthalmology and Optometry
Friday, 17 April 2015

An injection of stem cells into the eye may soon slow or reverse the effects of early-stage age-related macular degeneration (AMD), according to new research from scientists at Cedars-Sinai. Currently, there is no treatment that slows the progression of the disease, which is the leading cause of vision loss in people over 65.

"This is the first study to show preservation of vision after a single injection of adult-derived human cells into a rat model with age-related macular degeneration," said Shaomei Wang, MD, PhD, lead author of the study published in the journal STEM CELLS and a research scientist in the Eye Program at the Cedars-Sinai Board of Governors Regenerative Medicine Institute.

The stem cell injection resulted in 130 days of preserved vision in laboratory rats, which roughly equates to 16 years in humans. When animal models with macular degeneration were injected with induced neural progenitor stem cells, which derive from the more commonly known induced pluripotent stem cells, healthy cells began to migrate around the retina and formed a protective layer. This protective layer prevented ongoing degeneration of the vital retinal cells responsible for vision.

Cedars-Sinai researchers in the Induced Pluripotent Stem Cell (iPSC) Core, directed by Dhruv Sareen, PhD, with support from the David and Janet Polak Foundation Stem Cell Core Laboratory, first converted adult human skin cells into powerful induced pluripotent stem cells (iPSC), which can be expanded indefinitely and then made into any cell of the human body. In this study, these induced pluripotent stem cells were then directed toward a neural progenitor cell fate, known as induced neural progenitor stem cells, or iNPCs.

"These induced neural progenitor stem cells are a novel source of adult-derived cells which should have powerful effects on slowing down vision loss associated with macular degeneration," said Clive Svendsen, PhD, director of the Board of Governors Regenerative Medicine Institute and contributing author to the study. "Though additional pre-clinical data is needed, our institute is close to a time when we can offer adult stem cells as a promising source for personalized therapies for this and other human diseases."

Next steps include testing the efficacy and safety of the stem cell injection in preclinical animal studies to provide information for applying for an investigational new drug. From there, clinical trials will be designed to test potential benefit in patients with later-stage age-related macular degeneration.

 
Carnival Game Mimics Eye Growth PDF
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Ophthalmology and Optometry
Friday, 10 April 2015

Coin Pusher MachineThe motion of coins in a "Penny Pusher" carnival game is similar to the movement of cells in the eye's lens, as described in a new study published in Investigative Ophthalmology & Visual Science (IOVS). This new insight may help scientists understand how the eye maintains its precise shape -- critical for clear vision -- and how cataracts develop.

"If the size, shape or position of the eye is not carefully regulated, we simply will not see clearly," said author Steven Bassnett, PhD, of Washington University School of Medicine, Department of Ophthalmology and Visual Sciences. "However, the mechanisms that tightly control the growth of the eye remain largely unknown."

The recently published paper, The Penny Pusher: A Cellular Model of Lens Growth, describes how Bassnett's group studied mouse eyes for almost four years to learn more about how the eye's growth is regulated. During that time, they tracked where cells were multiplying on the surface of the eye's lens, the spherical, crystal clear portion of the eye just behind the iris (the colored ring near the eye's surface).

Experiments revealed that cells were primarily multiplying in a narrow line on the lens' surface. As new cells formed, they pushed their neighboring cells towards the lens' equator. Cells already at the equator were then pushed away from the surface and into the center of the lens.

This sequence of cellular motion -- where the addition of new cells push existing cells down into the center of the lens -- is similar to the movement of coins in the Penny Pusher carnival game. In the game, a player adds coins to a moving, elevated platform covered in other coins, causing coins at the far edge to fall onto a lower, larger platform and eventually to where the player can collect them.

"We made a physical model of the lens equator using layers of pennies to simulate the division and migration of the lens cells. Our Penny Pusher model looked very similar to [the carnival game]," said Bassnett.

Not only does the Penny Pusher model offer new insight into the regulation of the eye's shape, it suggests a possible mechanism for the development of cataracts. A cataract happens when the lens goes from crystal clear to cloudy, blurring one's vision.

According to the researchers, if a narrow line of cells on the lens' surface are forming new cells, then those relatively few cells could have a massive effect on the clarity of the lens. "We are currently examining whether mutations in the DNA of individual lens cells can be transmitted to large numbers of lens cells, potentially influencing the clarity of the tissue and resulting in cataract," explained Bassnett.

The researchers involved in this study believe that future success in this area of research could one day be credited to a seemingly unrelated carnival game.

 
Eyeliner Makeup May Cause Eye Problems PDF
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Ophthalmology and Optometry
Wednesday, 08 April 2015

eyelinerResearch by a scientist at the University of Waterloo's Centre for Contact Lens Research (CCLR) cautions that eyeliner on the inner eyelid run the risk of contaminating the eye and causing vision trouble. The study examined how eyeliner applied to the “waterline,” the inner part of the eyelash line, moves onto the tear film - the thin, wet layer that protects the eye.

Dr. Alison Ng, at the Centre for Contact Lens Research at Waterloo, directed the study when she was at Cardiff University in Wales. In her research, Ng captured more than 200 frames of video at timed intervals of her subject’s eyes. She and her research team then used specialized software to count every tiny particle of glitter that appeared on the surface of the eye and the results were clear -- when we apply makeup along the waterline more eyeliner moves into the tear film.

While that's not good news for anyone, Ng's research showed that the makeup gets flushed away by your tears within a couple of hours. But people who wear contact lenses run bigger risks because the makeup can get trapped by the lenses and affect your vision. Contact lenses add a physical barrier and lenses worn for multiple days are especially problematic because they continually re-introduce and collect unwanted debris, cautions Ng. "This can create cloudiness in contact lenses and disrupt vision," she says. "For anyone who wears heavy makeup or enjoys regularly applying beauty products around the eye, I would recommend daily disposable lenses for optimal cleanliness and comfort."

Anyone with dry eyes -- thanks to genetics, or environment, or staring at a screen all day -- may also be susceptible to more noticeable irritation, Ng says. Her study used healthy females without contact lenses as a baseline, but the connection to dry eyes and contacts is obvious. Makeup residue floating in the tear film is something optometrists see nearly every day, she says. What she wondered is: just much makeup is moving from where we want it to where we don’t?

The findings appeared in the recent issue of Eye and Contact Lens, the journal of the Contact Lens Association of Ophthalmologists.

 
Simple Test To Predict Which Kids Will Become Nearsighted PDF
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Ophthalmology and Optometry
Tuesday, 07 April 2015

Eye Test ChildrenA study spanning 20 years has identified a single test that can predict which kids will become nearsighted by the eighth grade: a measure of their current refractive error. The refractive error, or eyeglasses prescription, results from mismatches in the size and optical power of the eye that lead to blurry vision. The study also counters the notion that near work such as frequent reading or sitting too close to the television can bring on myopia, or nearsightedness.

"Near work has been thought to be a cause of myopia, or at least a risk factor, for more than 100 years. Some of the studies that led to that conclusion are hard to refute," said Karla Zadnik, professor and dean of the College of Optometry at The Ohio State University and lead author of the study. "In this large dataset from an ethnically representative sample of children, we found no association."

These results could help set a standard for eye exam recommendations for school-aged children and could be used to identify kids who would be good candidates for testing of experimental therapies designed to prevent myopia, Zadnik said.

The study involved 4,512 children between first and eighth grades. When they were between the ages of 6 and 11 years, children with normal vision were evaluated at this range of baseline ages and at least two additional annual visits. Over the course of the study, 414 kids became nearsighted between second and eighth grades.

The primary research question: "What measures could we have done in first grade to predict who was going to need glasses by the eighth grade?" Zadnik said. She and colleagues assessed 13 potential risk factors for nearsightedness to determine the strongest single predictor or set of predictors that could identify those children most likely to develop myopia. These included physical measures of the eye as well as reports from parents about their children's activities.

The research confirmed that eight of the 13 expected risk factors did indeed increase the likelihood that kids would become nearsighted. One important risk factor was having two nearsighted parents. The most surprising exception was near work. Statistical analysis, however, showed that the refractive error at baseline was the best predictor in children at a young age that they would develop myopia by their teen years.

In an eye exam, clinicians measure refractive error by changing lenses as patients view a distant eye chart and asking, "Which is better, one or two?" In this study, scientists used an auto-refractor to measure the children's eyes.

In people with normal vision, the eyeball grows along with the rest of the body and is programmed to stop growing at a point that sustains clear vision. In people with myopia, the typically spherical eyeball becomes elongated, resembling the shape of a grape or an olive. Kids who will grow up with normal vision are actually slightly farsighted when they are in first grade. So the potential for future myopia can be detected at this young age via a refractive error measure that reveals little to no farsightedness.

For example, the study showed that a 6-year-old child with less farsightedness is at greater risk for developing myopia sooner. The older the child, the more effective the refractive error is as a predictor of nearsightedness onset by age 13. So even in first-graders, it is possible to use this measure to help parents plan a schedule of eye exams for their children that will appropriately catch vision problems that require correction.
Nine years ago, the researchers reported data from this study suggesting that children who spent more time outdoors were less likely to become nearsighted. That association held true through the conclusion of the research, but the reasons behind that finding remain a mystery, Zadnik said. Statistically, however, that association is not strong enough to serve as a predictor.

The research is published in the April 2, 2015, issue of the journal JAMA Ophthalmology.

 
FDA Approves Treatment for Diabetic Retinopathy PDF
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Ophthalmology and Optometry
Tuesday, 31 March 2015

The U.S. Food and Drug Administration (FDA) has expanded the approved use for Eylea (aflibercept) injection to treat diabetic retinopathy in patients with diabetic macular edema.

Diabetic retinopathy (DR) is the most common diabetic eye disease and is a leading cause of blindness in adults in the United States. According to the Centers for Disease Control and Prevention, diabetes (type 1 and type 2) affects more than 29 million people in the United States and is the leading cause of new blindness among people ages 20 to 74 years. In 2008, 33 percent of adults with diabetes aged 40 years or older had some form of DR. In some cases of DR with diabetic macular edema (DME), abnormal new blood vessels grow on the surface of the retina. Severe vision loss or blindness can occur if the new blood vessels break.

In February, the FDA approved Lucentis (ranibizumab injection) 0.3 mg to treat DR in patients with DME.

Eylea is administered by a physician as an injection into the eye once a month for the first five injections and then once every two months. It is intended to be used along with appropriate interventions to control blood sugar, blood pressure and cholesterol.

The safety and efficacy of Eylea to treat DR in patients with DME were evaluated in 679 participants in two clinical studies where participants were randomly assigned to receive Eylea or macular laser photocoagulation, a laser-based treatment used to burn small areas of the retina. At week 100, participants being treated with Eylea showed significant improvement in the severity of their DR, compared to patients who did not receive Eylea.

The most common side effects associated with Eylea include bleeding of the conjunctiva (the tissue that lines the inside of the eyelids and covers the white part of the eye); eye pain; cataracts; floaters; increased pressure inside the eye (increased intraocular pressure); and separation of the interior jelly of the eye from the retina (vitreous detachment). Serious adverse reactions include infection within the eye (endophthalmitis) and retinal detachments.

The FDA granted breakthrough therapy designation to Eylea for the treatment of DR with DME. The FDA can designate a drug a breakthrough therapy at the request of the sponsor if preliminary clinical evidence indicates the drug may demonstrate a substantial improvement over available therapies for patients with serious or life-threatening conditions. The FDA also reviewed the new use for Eylea under the agency’s priority review program, which provides for an expedited review of drugs that demonstrate the potential to be a significant improvement in safety or effectiveness in the treatment of a serious condition.

The FDA previously approved Eylea to treat wet (neovascular) age-related macular degeneration, a condition in which abnormal blood vessels grow and leak fluid into the macula. Eylea is also approved to treat DME and macular edema secondary to retinal vein occlusions, both of which cause fluid to leak into the macula resulting in blurred vision. 

 
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