Category: Ophthalmology

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Mapping the ‘Light’ Seen by Closed Eyes could Help Prosthetic Eyes See Better

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Researchers at Monash University have identified a new way of mapping ‘phosphenes’ – the visual perception of the bright flashes we see when no light is entering the eye – to improve the outcome of surgery for patients receiving a cortical visual prosthesis.

Cortical visual prostheses are devices implanted onto the brain with the aim of restoring sight by directly stimulating the area responsible for vision, the visual cortex, bypassing damage to the retina of the eye or the optic nerve. Phosphenes, apparent flashes and patterns of lights, were described by the ancient Greeks and can be elicited by pressure, injury, disease, certain medications or direct electrical stimulation.

A typical prosthesis consists of an array of fine electrodes, each of which is designed to trigger a phosphene. Given the limited number of electrodes, understanding how electrodes can best be placed to generate useful perceived images becomes critical.

Published in the Journal of Neural Engineering, the study presents a more realistic simulation for cortical prosthetic vision.

As part of this researchers from the Department of Electrical and Computer Systems Engineering at Monash University, led by Associate Professor Yan Tat Wong, are honing in on the ideal distribution of phosphenes.

“Phosphenes are likely to be distributed unevenly in an individual’s visual field, and differences in the surface of the brain also affect how surgeons place implants, which together result in a phosphene map unique to each patient,” Associate Professor Wong said.

The study used a retinotopy dataset based on magnetic resonance imaging (MRI) scans, consulting with a neurosurgeon about realistic electrode implantation sites in different individuals, and applying a clustering algorithm to determine the most suitable regions to present stimuli.

Sighted participants recruited for the study were asked to test and verify the phosphene maps based on visual acuity and object recognition.

“We’re proposing a new process that incorporates our simulation paradigm into surgical planning to help optimise the implantation of a cortical prosthesis,” Associate Professor Wong said.

The process would begin with an MRI scan to plot the recipient’s brain surface in the area of the visual cortex. Potential implant locations would then be identified, and the simulation developed in the Monash research would be used to plot phosphene maps.

“We can use the metrics we computed to find practical implant locations that are more likely to give us a usable phosphene map, and we can verify those options through psychophysics tests on sighted participants using a virtual reality headset,” Associate Professor Wong said.

“We believe this is the first approach that realistically simulates the visual experience of cortical prosthetic vision.”

Source: Monash University

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Eyedrops instead of Injections for Age-related Macular Degeneration

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Retina showing reticular pseudodrusen. Although they can infrequently appear in individuals with no other apparent pathology, their highest rates of occurrence are in association with age-related macular degeneration (AMD), for which they hold clinical significance by being highly correlated with end-stage disease sub-types, choroidal neovascularisation and geographic atrophy. Credit: National Eye Institute

A new compound potentially could offer an alternative to injections for the millions of people who suffer from wet age-related macular degeneration (AMD). The condition causes vision loss due to the uncontrolled growth and leakage of blood vessels in the back of the eye. A new paper in Cell Reports Medicine finds that a small-molecule inhibitor can reverse damage from AMD and promote regenerative and healing processes.

The drug can also be delivered via eyedrops – an improvement over current treatments for AMD, which require repeated injections into the eye.

“The idea was to develop something that can be more patient-friendly and doesn’t require a visit to the doctor’s office,” said lead researcher Yulia Komarova, associate professor of pharmacology at University of Illinois Chicago.

Komarova’s compound targets the protein End Binding-3 in endothelial cells, which line the inside of blood vessels. In the new study, the researchers looked at whether inhibiting EB3 function could stop the damaging leakage associated with wet AMD.

Using computational drug design methods, the team developed a small molecule drug, End Binding-3 inhibitor (EBIN), that could be delivered externally via eyedrops instead of by injection. They then tested its effectiveness in animal models of wet AMD, finding that twice-daily treatment reduced eye damage within 2–3 weeks.

Further investigation found that the inhibitor worked by rolling back aging-related genetic modifications. Aging causes inflammation and hypoxia in the eye that leads to changes in gene expression associated with the cellular effects and symptoms of wet AMD. Komarova and colleagues found that the EB3 inhibitor they developed reversed these epigenetic changes, restoring gene expression to a normal, healthy state.

“We reduce the effects of the stressor on endothelial cells and we improve regenerative processes, accelerating healing,” Komarova said. “That can be tremendous for the function of the cells.”

Because blood vessel leakage and hypoxic stress also drive many other medical conditions, Komarova’s group is interested in testing the inhibitor in models of acute lung injury, diabetic retinopathy, stroke, heart disease and even the general effects of aging on the brain. They are also exploring whether an implantable lens, similar to a contact lens, could deliver the drug to the eye more effectively than eyedrops.

Source: University of Illinois Chicago

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Many Old People may be Unaware that They Have Glaucoma

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Research on 70-year-olds carried out at the University of Gothenburg, found that nearly 5% had glaucoma – with half of whom were unaware that they had the disease. The study also confirmed hereditary factors were involved in the disease and that intraocular pressure was normal in two-thirds of those newly diagnosed.

Glaucoma is a common eye disease that damages the optic nerve and thereby the field of vision and can lead to blindness. One of the most common risk factors for it is raised intraocular pressure, exceeding the normal range of 11–21mmHg.

The research, published in Acta Ophthalmologica, was carried out by Lena Havstam Johansson, a PhD student at the University of Gothenburg and a specialist nurse at Sahlgrenska University Hospital. The study shows that 4.8% of the 560 study participants examined by eye specialists had glaucoma.

“Of those who were diagnosed with glaucoma via the study, 15 people – or 2.7% of all participants – were unaware that they had the disease before being examined,” says Lena Havstam Johansson. “So half of those who turned out to have glaucoma were diagnosed because they took part in the study.”

For those who were newly diagnosed, the discovery of the disease meant they could start treatment with daily eye drops to reduce intraocular pressure, slowing the progression of optic nerve damage.

Glaucoma impacts some areas of life – but not others

People with glaucoma had similar levels of physical activity to those without the disease and did not smoke more, or drink more alcohol. They rated their overall quality of life as being just as good as others, they were not more tired or more depressed.

“This was a positive surprise, and was a finding that I hope can bring comfort to many people who have been diagnosed with glaucoma. It’s hard to live with a disease that gradually impairs vision, but life can still be good in many ways.”

By contrast, people with glaucoma reported that their vision-related quality of life was poorer.

“It’s harder to climb stairs, see curbs in the evening, and notice things in your peripheral vision. This means that people with glaucoma may avoid visiting others, or going to restaurants or parties, and instead stay at home. They lose their independence, and may feel frustrated about it.”

Ongoing study of 70-year-olds

The research was carried out as part of the H70 study, examining the health of older people, which has been conducted at the University of Gothenburg for fifty years. The H70 study continuously invites all 70-year-olds born in a certain year in Gothenburg to attend several comprehensive physical and cognitive examinations. The 1203 70-year-olds included in the glaucoma study were born in 1944. For these studies, 1182 participants answered written questions about their eye health and the presence of glaucoma in their family. Eye specialists at Sahlgrenska University Hospital also examined 560 of the participants.

The findings confirm that there are hereditary factors behind the disease, as those diagnosed with glaucoma were more likely to have a close relative with the same diagnosis. The results also confirm that glaucoma involves higher intraocular pressure, although they also show that the majority of those who were newly diagnosed (67%) still had normal eye pressure.

During the early stages of the disease, the healthy eye can compensate for the loss of vision, meaning that many people believe their vision is as good as before. These studies confirm that glaucoma often does not initially involve a loss of visual acuity, which may make it harder to detect the disease.

Source: University of Gothenburg

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A Smart Contact Lens Battery Powered by Tears

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Singapore scientists have developed a flexible battery as thin as a human cornea, which can store electricity when immersed in a saline solution such as tears. The scientists described their research in Nano Energy, and believe that this technology could one day power smart contact lenses.

Smart contact lenses are high-tech contact lenses capable of displaying visible information on the cornea and can be used to access augmented reality as well as monitoring health and their normal function of correcting vision. But they need power, and existing rechargeable batteries rely on wires or induction coils that contain metal and are unsuitable for use in the human eye, as they are uncomfortable and present risks to the user.

The battery, developed by Nanyang Technological University, is made of biocompatible materials and does not contain wires or toxic heavy metals, such as those in lithium-ion batteries or wireless charging systems. It has a glucose-based coating that reacts with the sodium and chloride ions in the saline solution surrounding it, while the water the battery contains serves as the ‘wire’ or ‘circuitry’ for electricity to be generated.

The battery could also be powered by human tears as they contain sodium and potassium ions, at a lower concentration. Testing the current battery with a simulated tear solution, the researchers showed that the battery’s life would be extended an additional hour for every twelve-hour wearing cycle it is used. The battery can also be charged conventionally by an external power supply.

Associate Professor Lee Seok Woo, from NTU’s School of Electrical and Electronic Engineering (EEE), who led the study, said: “This research began with a simple question: could contact lens batteries be recharged with our tears? There were similar examples for self-charging batteries, such as those for wearable technology that are powered by human perspiration.

“However, previous techniques for lens batteries were not perfect as one side of the battery electrode was charged and the other was not. Our approach can charge both electrodes of a battery through a unique combination of enzymatic reaction and self-reduction reaction. Besides the charging mechanism, it relies on just glucose and water to generate electricity, both of which are safe to humans and would be less harmful to the environment when disposed, compared to conventional batteries.”

The research team has filed for a patent through NTUitive, NTU’s innovation and enterprise company. They are also working towards commercialising their invention.

Cry me a current

The team demonstrated their invention using a simulated human eye. The battery, which is about 0.5 millimetres-thin generates electrical power by reacting with the basal tears – the constant tears that create a thin film over our eyeballs – for the devices embedded within the lenses to function.

The flexible and flat battery discharges electricity through a process called reduction when its glucose oxidase coating reacts with the sodium and chloride ions in the tears, generating power and current within the contact lenses.

The team demonstrated that the battery could produce a current of 45 microamperes and a maximum power of 201 microwatts, which would be sufficient to power a smart contact lens.

Laboratory tests showed that the battery could be charged and discharged up to 200 times. Typical lithium-ion batteries have a lifespan of 300 to 500 charging cycles.

The team recommends that the battery should be placed for at least eight hours in a suitable solution that contains a high quantity of glucose, sodium and potassium ions, to be charged while the user is asleep.

Source: Nanyang Technology University

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Rebuilding Retinas with Nanotechnology ‘Scaffolds’

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Anglia Ruskin University (ARU) researchers have found a to create a 3D ‘scaffold’ to grow cells from the retina -paving the way for potential new ways of treating a common cause of blindness. Their nanotechnology-based approached is detailed in the journal Materials & Design.

The researchers have been working on a way to successfully grow retinal pigment epithelial (RPE) cells that stay healthy and viable for up to 150 days. RPE cells sit just outside the neural part of the retina and, when damaged, can cause vision to deteriorate.

It is the first time this technology, called ‘electrospinning’, has been used to create a scaffold on which the RPE cells could grow, and could revolutionise treatment for one of age-related macular degeneration, one of the world’s most common vision complaints.

When the scaffold is treated with a steroid called fluocinolone acetonide, which protects against inflammation, the resilience of the cells appears to increase, promoting growth of eye cells. These findings are important in the future development of ocular tissue for transplantation into the patient’s eye.

Age-related macular degeneration (AMD) is a leading cause of blindness in the developed world and is expected to increase in the coming years due to an ageing population. Recent research predicted that 77 million people in Europe alone will have some form of AMD by 2050.

AMD can be caused by changes in the Bruch’s membrane, which supports the RPE cells, and breakdown of the choriocapillaris, the rich vascular bed that is adjacent to the other side of the Bruch’s membrane.

In Western populations, the most common way sight deteriorates is due to an accumulation of lipid deposits called drusen, and the subsequent degeneration of parts of the RPE, the choriocapillaris and outer retina. In the developing world, AMD tends to be caused by abnormal blood vessel growth in the choroid and their subsequent movement into the RPE cells, leading to haemorrhaging, RPE or retinal detachment and scar formation.

The replacement of the RPE cells is among several promising therapeutic options for effective treatment of sight conditions like AMD, and researchers have been working on efficient ways to transplant these cells into the eye.

Lead author Professor Barbara Pierscionek, Deputy Dean (Research and Innovation) at Anglia Ruskin University (ARU) said: “This research has demonstrated, for the first time, that nanofibre scaffolds treated with the anti-inflammatory substance such as fluocinolone acetonide can enhance the growth, differentiation, and functionality of RPE cells.

“In the past, scientists would grow cells on a flat surface, which is not biologically relevant. Using these new techniques. the cell line has been shown to thrive in the 3D environment provided by the scaffolds.

“This system shows great potential for development as a substitute Bruch’s membrane, providing a synthetic, non-toxic, biostable support for transplantation of the retinal pigment epithelial cells. Pathological changes in this membrane have been identified as a cause of eye diseases such as AMD, making this an exciting breakthrough that could potentially help millions of people worldwide.”

Source: Angela Ruskin University

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No Cure for Myopia Progression in Sight as Eyedrops Trial Flops

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A US study shows that use of low-dose atropine eyedrops, commonly used in a higher dose to treat lazy eye, was no better than a placebo at slowing myopia progression and elongation of the eye among children treated for two years.

The first randomised controlled trial of its kind aimed at identifying an effective way to manage myopia was published last week in JAMA Ophthalmology. It was conducted by the Pediatric Eye Disease Investigator Group at at Vanderbilt University Medical Center (VUMC) and 11 other hospitals and practices across the United States and funded by the National Eye Institute (NEI).

“We found, interestingly, and honestly shockingly, that there was no difference in the use of 0.01% atropine and placebo in treating these children who ranged in age from 5 to 12,” said associate professor Lori Ann Kehler, OD, and the Vanderbilt site principal investigator for the study.

The onset of myopia usually occurs between the ages of 7 and 16 when developing eyes can start growing too long axially (from front to back). Instead of focusing images on the retina, images of distant objects are focused at a point in front of the retina which causes people to have poor distance vision while their near vision remains unchanged.

The condition results in the need for eyeglasses to improve distance vision, and it can also result in medical complications and serious uncorrectable vision loss later in life, like retinal detachments or myopic macular degeneration.

The study contradicts earlier studies from East Asia that showed the small dose of atropine is effective in slowing progression of myopia.

In 2017 the Academy of Ophthalmology endorsed the findings from East Asia saying that although the FDA had not approved atropine for this use, there was sufficient evidence for prescribing the low dose for myopia. Ophthalmologists across the country, including at VUMC, began to offer the prescription to young patients with myopia.

“That was a really exciting finding at the time because we had had no treatment options for many years,” Kehler said. The prescription of atropine for treating myopia is not covered by most insurance plans.

“The incidence of myopia is increasing worldwide,” Kehler said. “By 2030 it’s predicted that 39 million people in the US will have myopia. By 2050 that number is expected to increase to more than 44 million people in the US and to 50% of the global population. Once it’s detected in children, it tends to get worse every year,” she said. “Investigators all over the world have tried strategies to intervene, to either stop or slow the worsening of myopia.”

Kehler said it is not known why the incidence of myopia is increasing. “There are several theories. Some believe it’s the increase in the use of screens and screen time, but myopia was increasing even before screens were part of children’s lives. Others think it has to do with industrialisation. We were an agricultural society. We were outside more. We weren’t reading. We weren’t looking up close all day. Really, the prevailing thought is whether we’re at a screen or looking at a math book or reading most of the day, we think the lack of sunlight and sustained near effort is what’s causing the increase of myopia.”

Kehler said the percentage of children with myopia using the atropine drop at VUMC is low and estimates fewer than 5% of children with myopia are using the drops nationally.

Going forward, eye specialists should have a frank discussion with parents of children with myopia about the conflicting data between the Asian studies and the new U.S. study.

“The absence of a treatment benefit in our US-based study, compared to East Asian studies, may reflect racial differences in atropine response. The study enrolled fewer Asian children, whose myopia progresses more quickly, and included Black children, whose myopia progresses less quickly compared with other races,” noted the study’s lead co-author, Michael X. Repka, MD, professor of Ophthalmology at Johns Hopkins University, in a news release from the NEI.

“All the studies have shown the drops are safe, so we aren’t putting children at risk if we continue to prescribe the 0.01%,” Kehler said. “But we are telling them there is a difference in these studies and it might have to do with your genetics; it might be that it’s more effective in children from Asia than in the U.S. population,” she said.

Further study is needed, Kehler said. The next step is likely to study a higher dose of atropine to see if children in the U.S. experience a benefit.

The LAMP study out of Hong Kong found that 0.05% might be more effective.

Kehler said other groups are studying the use of red-light therapy to slow the progression of myopia, and there are also new eyeglass lenses that have been developed to slow the progression of myopia, but they are not yet available in the U.S.

“It’s much harder to get drops in very young children,” Kehler said. “But if we had a spectacle option, that would open the door to treating our younger patients.”

Myopia usually stabilises in about half of children around 16 years of age and among an increasingly larger percentage as they get older. By their early 20s, about 10% of individuals with myopia will continue to grow more nearsighted, and by age 24 that percentage is 4%.

Source: Vanderbilt University Medical Center

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Contrary to Prior Belief, T Cells Even Protect the Cornea

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Researchers have discovered that the immune cells guarding the healthy human cornea from pathogens and inflammation are T cells, and dendritic cells, as previously thought. The discovery, published in PNAS, redefines current understanding of the immune cell landscape in the cornea of a healthy human eye. It builds on the team’s previous research in Cell Reports that showed that T cells protect the eye against virus infection in mice.

The collaborative research team jointly developed a new imaging technique as part of their investigation.

Research leader Professor Scott Mueller, from the Department of Microbiology and Immunology at the Doherty Institute explained that our knowledge of the various immune cell types in the human cornea is important for establishing the eye’s protective mechanisms against pathogens and disease.

“By combining our newly developed imaging technique with other advanced analytical approaches, we were able to discover that a significant number of cells at the surface of the healthy cornea are actually T cells,” said Professor Mueller.

“Until now, these cells were mistakenly classified as dendritic cells based on static imaging. This completely changes the current dogma in the field that only dendritic cells are present in the healthy cornea.”

The study’s first author, University of Melbourne’s Associate Professor Laura Downie said that being able to dynamically capture the cells’ normal behaviour, and in response to inflammation, provides unique understanding into the immune response in the eye.

“Using our non-invasive imaging approach, which we term Functional In Vivo Confocal Microscopy (Fun-IVCM), we have been able to see that these T cells move around quickly and interact with other cells and nerves in the outermost layer of the cornea. We also captured different cell dynamics in response to contact lens wear and in allergic eye disease, and quantified how these behaviours are modulated by drug treatments,” said Associate Professor Downie.

“These findings reshape our understanding of the distinct immune cell subsets in the human cornea, and how they respond to different stimuli. Using Fun-IVCM, we can achieve rapid, real-time insight into the cellular immune responses in living humans, in this accessible peripheral sensory tissue.”

Senior author Dr Holly Chinnery, also of the University of Melbourne, added that the new research will have major implications for the medical and immunology fields, including for patients and practitioners.

“Because this new technique involves non-invasive, time-lapse imaging of the human cornea, Fun-IVCM could be used in clinics directly to assess immune responses and ocular health. It could even be used for general immune system health,” said Dr Chinnery.

“Changes in T cells and behaviour could be used as a clinical biomarker of disease and assist with treatments.”

Source: The Peter Doherty Institute for Infection and Immunity

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Atropine Eyedrops Fail to Slow Myopia Progression in US Children

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Use of low-dose atropine eyedrops (concentration 0.01%) was no better than placebo at slowing myopia progression and elongation of the eye among children treated for two years, according to a randomised controlled trial conducted in the US. The trial aimed to identify an effective way to manage this leading and increasingly common cause of refractive error, which can cause serious uncorrectable vision loss later in life. Results from the trial, published in JAMA Ophthalmology, contradict those from recent trials in East Asia.

The study was conducted by the Pediatric Eye Disease Investigator Group (PEDIG) and funded by the National Eye Institute (NEI).

“The overall mixed results on low-dose atropine show us we need more research. Would a different dose be more effective in a US population? Would combining atropine with other strategies have a synergistic effect? Could we develop other approaches to treatment or prevention based on a better understanding of what causes myopia progression?” said Michael F. Chiang, MD, director of the NEI, which is part of the National Institutes of Health.

Identifying an optimal approach for preventing high (advanced) myopia is urgently needed given the escalating prevalence of myopia overall and the risk of it progressing to high myopia. By 2030, it’s predicted that 39 million people in the U.S. will have myopia. By 2050, that number is expected to grow to 44 million in the U.S. and to 50% of the global population.

Much stronger concentrations of atropine eyedrops (0.5-1.0%) have long been used by pediatric eye doctors to slow myopia progression. While effective, such doses cause light sensitivity and blurry near vision while on the nightly eyedrops. Thus, there is interest in clinical studies assessing lower concentrations that have been shown to have fewer side effects.

“The absence of a treatment benefit in our US-based study, compared with East Asian studies, may reflect racial differences in atropine response. The study enrolled fewer Asian children, whose myopia progresses more quickly, and included Black children, whose myopia progresses less quickly compared with other races,” noted the study’s lead co-author, Michael X. Repka, M.D., professor of ophthalmology, Johns Hopkins University.

For the study, 187 children ages 5 to 12 years with low-to-moderate bilateral myopia were randomly assigned to use nightly atropine (0.01%) (125 children) or placebo (62 children) eyedrops for two years. Study participants, their parents, and the eye care providers were masked to the group assignments.

After the treatment period, and 6 months after treatment stopped, there were no significant differences between the groups in terms of changes in degree of myopia compared with baseline. Nor were there significant differences in axial length within the two groups when compared with baseline measurements.

“It’s possible that a different concentration of atropine is needed for US children to experience a benefit,” noted the study’s other lead co-author, Katherine K. Weise, OD, professor, University of Alabama at Birmingham. “Clinical researchers could evaluate new pharmaceuticals and special wavelengths of light in combination with optical strategies, like special glasses or contact lenses, to see what works in reducing the progression of myopia.”

Among children, myopia will stabilise in about half of children around age 16 years, and among an increasingly larger percentage as they get older. By their early twenties, about 10% of individuals with myopia will continue to grow more nearsighted, and by age 24 years that percentage is 4%.

“Vision scientists may help us figure out what’s different about the myopic eye, even among different races and ethnicities, to help create new treatment strategies,” she said. It will take a real convergence of eye research to solve the environmental, genetic, and structural mystery of myopia.”

Source: NIH/National Eye Institute

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Thinning of the Retina is an Early Marker of MS

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Retina and nerve cells. Credit: NIH

For the first time, a study has shown that diagnosis of multiple sclerosis (MS) can be significantly improved by additionally measuring the thickness of retinal layers in the eye in a currently existing procedure. Use of the procedure helps to detect the condition at an earlier stage and predict its progression more accurately, which can help to improve patient outcomes. The findings have been published in the journal Neurology.

As part of their investigation, the research team headed by Gabriel Bsteh and Thomas Berger collaborated with ophthalmology colleagues examine 267 MS patients over five years. Their research built on study results published in 2022, which showed that MS relapse-related damage to the retina reflects the degree of damage caused to the patient’s brain. The previous study also demonstrated that a 5µm reduction in the thickness of the retinal layer following optic neuritis indicated a doubling of the risk of permanent disability after the next relapse. Thanks to the latest research with the large cohort of MS patients, the research team has confirmed that the thickness of the retinal layer can be used as a precise biomarker to assist early diagnosis.

Diagnostic procedure already available

The researchers used a procedure known as optical coherence tomography (OCT) to measure the thickness of the retinal layer. An imaging method that uses infrared light, OCT allows for the generation of high-resolution, three-dimensional images of extremely thin layers of tissue measuring just a few µm. OCT is also a tool for diagnosing and evaluating the progression of eye diseases such as glaucoma. “So we already have this procedure at our disposal,” commented Gabriel Bsteh, first author of the study. He added: “If we use optical coherence tomography alongside the current criteria to diagnose MS, we obtain significantly more accurate results at a much earlier stage. This means we can initiate treatment measures sooner, which considerably improves the long-term prognosis for patients.”

The retina: a window to the brain

Multiple sclerosis is an autoimmune, chronic inflammatory disease that causes inflammation and loss of nerve cells throughout the nervous system. For the most part, patients are unable to feel the consequences of this damage to begin with, so the condition often goes undiagnosed until a late stage, meaning that valuable time is lost during which effective treatment could have been administered. Given that early detection and prognosis of the disease’s progression play a decisive role in MS cases, medical researchers have been trying to find improved detection methods for some time now to help avert serious consequences such as impaired mobility and blindness as far as possible. “We have identified a new biomarker for MS diagnosis, namely the retinal layer thickness, which can be likened to a window to the brain,” said Gabriel Bsteh, summing up the study’s key finding. In the next phases of research, the focus will turn to the importance of retinal layer thickness in measuring responses to MS treatment.

Source: Medical University of Vienna

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Atropine Eyedrops Shown to Slow Progression of Myopia in Children

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The first drug therapy to slow the progression of nearsightedness in children is a step closer after the results of a successful clinical trial.

The results of the CHAMP (Childhood Atropine for Myopia Progression) trial were published in JAMA Ophthalmology. The three-year study found that a daily drop in each eye of a low dose of atropine, a drug used to dilate pupils, was better than a placebo at limiting eyeglass prescription changes and inhibiting elongation of the eye in nearsighted children aged six to 10.

About one in three adults worldwide is nearsighted, and the global prevalence of myopia is predicted to increase to 50% by 2050. Though one federally approved contact lens can slow progression of nearsightedness, no pharmaceutical products are approved in the US or Europe to treat myopia.

That elongation of the eyeball leads to myopia which starts in young children and progresses into the teen years before levelling off in most people. In addition to requiring life-long vision correction, nearsightedness increases the risk for retinal detachment, macular degeneration, cataracts and glaucoma later in life – and most corrective lenses don’t do anything to stop myopia progression.

“The idea of keeping eyeballs smaller isn’t just so people’s glasses are thinner – it would also be so that in their 70s they don’t suffer visual impairment,” said lead study author Karla Zadnik, professor and dean of the College of Optometry at The Ohio State University.

“This is exciting work for the myopia research community, which I’ve been part of for 35 years. We’ve talked about treatment and control for decades,” she said. “And it’s exciting to think that there could be options in the future for millions of children we know are going to be myopic.”

Animal studies years ago hinted at atropine’s ability to slow the growth of the eye, but the full-strength drug’s interference with near vision and concerns about pupil dilation hindered early considerations of its potential as a human therapy for myopia. More recent research has suggested a low dose of atropine might be the ticket.

This new double-masked, randomised phase 3 trial assessed the safety and effectiveness of two low-dose solutions, with atropine concentrations of either .01% or .02%, versus placebo. Treatment for each of the 489 children ages six to 10 assessed for the drug’s effectiveness consisted of one daily drop per eye at bedtime, which minimised the disruption of any blurring effects atropine might have on vision.

Researchers were a bit surprised to find that the most significant improvements at all time points compared to placebo resulted from the solution containing .01% of atropine. Though the .02% atropine formulation was also better at slowing progression of myopia than placebo, the results were less consistent.

“The .01% story is clearer and more obvious in terms of significantly slowing both the growth of the eye as well as then resulting in a lower glasses prescription,” Zadnik said.

Including a measure of the eye’s growth was a key component of the study because “the field is actually moving toward axial elongation being as important as, or more important than, the glasses prescription in terms of the most meaningful outcome,” she said. “If we’re trying to slow eye growth to prevent bad outcomes for people in their 80s, measuring the eye growth directly is really important.”

The drugs’ safety was assessed in a larger sample of 573 participants that also included children as young as 3 and up to age 16. Both low-dose formulations were safe and well tolerated. The most common side effects were sensitivity to light, allergic conjunctivitis, eye irritation, dilated pupils and blurred vision, although reports of these side effects were few.

The CHAMP trial was the first study of low-dose atropine to include placebo controls for three years and to involve a large, diverse population recruited from 26 clinical sites in North America and five countries in Europe. In a second section of the trial, researchers are evaluating how the eyes respond when the treatment is over.

Source: Ohio State University