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Aug 1st 2018
Macular Degeneration: Symptoms, Diagnosis and Treatments
Nearly 2 million Americans ages 40 and older are affected by age-related macular degeneration (AMD), which is a leading cause of vision loss in older adults, according to estimates from the Centers for Disease Control and Prevention (CDC). This eye disorder is more likely to occur after age 60, but it can occur at earlier ages.
Also called macular degeneration, AMD causes damage to the macula, the part of the eye needed for sharp, central vision, meaning the ability to view objects that are straight ahead. Central vision is needed for seeing objects clearly and for doing such common activities as driving, reading, writing, cooking, dialing a phone and recognizing faces.
Macular degeneration is deterioration in the central area of the retina, called the macula, said Dr. Mark Fromer, an ophthalmologist and retina specialist at Lenox Hill Hospital, in New York City.
The macula is located in the center of the retina, the inside back layer of the eyeball that converts light and images into electrical signals that get sent to the brain. AMD can occur in one or both eyes, and it usually does not affect peripheral (side) vision.
The eye disorder is more common among people as they get older. AMD typically develops gradually and isn't painful, so early symptoms can be mistaken for normal age-related vision changes. In other people, the disease progresses more quickly, and may lead to vision loss in one or both eyes.
"If a patient notices any distortion in one eye, he or she should see an ophthalmologist immediately," Fromer told Live Science. Visual distortions may include the symptoms described below.
According to the Mayo Clinic, symptoms of AMD include:
· Straight lines or faces appearing wavy
· Doorways seeming crooked
· Objects appearing smaller or farther away
· Increasing difficulty adapting to low light levels
· Decreasing color intensity or brightness
· Difficulty recognizing faces
· Increasing vision haziness
· Blurry or blind spots in central vision
· Causes & risk factors
The exact causes of AMD aren't known, but the risk of developing macular degeneration can increase with age. Genetics, certain physical conditions and lifestyle habits can also play a role. According to the National Eye Institute (NEI), these risk factors include:
· Being age 65 and older (but it can occur earlier)
· Family history of AMD
· High blood pressure
· High cholesterol
· Being Caucasian
· Being female
· Having blue eyes
· Diet low in fruits and vegetables
There are two types of AMD: wet and dry.
Dry AMD (also called geographic atrophy) is the most common form of macular degeneration affecting about 80 percent of people with AMD. It generally affects both eyes and its symptoms progress slowly. Dry AMD occurs when light-sensitive cells in the macula gradually deteriorate. Yellow deposits of protein, called drusen, form behind the retina. Drusen can dislodge the macula from its usual location in the eye. The size and number of drusen often indicate how severe dry AMD has become. Most people develop very small drusen as they get older, but when drusen are numerous or large, dry AMD is usually more advanced, according to the NEI. Changes in the pigment of the retina can also be a sign of the disease.
Wet AMD (also called neovascular AMD) is the less common form, occurring in only about 10 to 15 percent of all cases, but it is more serious than dry AMD and can trigger rapid vision loss, according to the NEI. It develops when abnormal blood vessels grow underneath the retina and leak blood or other fluids, causing scarring and damage to the macula.
AMD has three stages, partially defined by the size and number of drusen beneath the retina. People in early-stage AMD have medium-sized drusen and usually no vision loss. People with intermediate AMD have large drusen, pigment changes in the retina, or both, and most of those affected don't experience any vision loss. People with late AMD have drusen and vision loss, and can develop either dry or wet AMD, according to the NEI.
Diagnosis & tests
AMD may be suspected in people over 60 who experience recent changes in the center of their field of vision.
Several eye tests can help confirm the diagnosis, including:
Visual acuity test: An eye chart is used to measure how well a person can see at different distances.
Dilated eye exam: The pupils are dilated with eye drops so that the optic nerve and retina, located in the back of the eye, can be examined for signs of AMD, according to the Mayo Clinic. A special magnifying lens is used to perform this eye exam, during which an eye doctor is looking for fluid or blood or a mottled appearance. This indicates the presence of drusen under the retina.
Amsler grid: People are asked to look at this grid, which resembles a checkerboard with a black dot in the center. This grid can test for defects in a person's central vision If straight lines in the grid appear wavy or some lines appear to be missing, AMD is more likely.
Angiogram: During this test, a special camera can take pictures of the retina after a colored dye has been injected into a vein in the arm. This dye then travels to the blood vessels in the eye and highlights them. AMD may be present if the images show leaking blood vessels or retinal changes.
Tomography: This painless imaging test uses beams of light to identify whether retinal thinning, thickening or swelling associated with AMD is present, according to the Mayo Clinic.
Treatments & medication
There is currently no treatment for the dry form of AMD, but some people who have a lot of drusen may benefit from taking certain nutritional supplements. Taking a daily high-dose combination of antioxidant vitamins and minerals may slow the progression of dry AMD from the intermediate stage to the advanced stage by as much as 25 percent, according to a large study conducted by the NEI. The formulation includes:
· 500 milligrams (mg) of vitamin C
· 400 International Units (IU) of vitamin E
· 10 mg of lutein
· 2 mg of zeaxanthin
· 80 mg of zinc (as zinc oxide)
· 2 mg of copper (as cupric oxide)
Wet AMD has three main treatments, not all of which are appropriate for every person. They include:
· Injections into the affected eye with a drug that blocks a growth factor stimulating abnormal blood vessel development in the retina
· Laser surgery, uses a high-energy laser beam to seal leaky blood vessels behind the retina
· Photodynamic therapy, which includes the injection of a light-activated drug into the bloodstream. After the injection, a light is shined into the eye for 90 seconds, causing the drug to destroy new blood vessel growth, according to the NEI.
Several lifestyle changes can help AMD patients cope better with resulting vision loss, according to the Mayo Clinic. These include using magnifying lenses and glasses; adjusting computer font size and brightness level; using adaptive appliances such as clocks and telephones with extra-large numbers; trying large-print books, tablet computers and audio books; and brightening room light levels to make reading and other activities easier.
July 22nd 2018
How to spot age-related macular degeneration
Fifteen years ago, Lorna Blakeney thought she had a lump of mucus in her eye. “I was sitting reading a book after lunch and suddenly realised there was something in my left eye. I tried to blink and rub it away. I thought a night’s sleep would help. But in the morning, it was still there. I didn’t do anything about it for two weeks, which was stupid of me, especially as my daughter is an optometrist.”
Lorna’s daughter sent her mum straight to an ophthalmologist. “But it was too late. I was diagnosed with wet age-related macular degeneration (AMD); there was no treatment in those days and I was told there was an 82% chance that my other eye would go, too.”
Lorna’s daughter, Dr Sue Blakeney, is a clinical adviser at the College of Optometrists. She says that what happened to her mum is not uncommon. “Macular degeneration causes damage to the part of the retina responsible for central vision. It affects one eye first, so you often don’t notice it unless you close one eye at a time; you can be almost blind in one eye and not be aware of it.” Lorna is even more pithy: “You have two eyes – make sure you compare them. One is often stronger than the other, but if things change, get help.”
Ophthalmologist Pearse Keane of Moorfields eye hospital in London says that AMD is the most common cause of irreversible sight loss in the UK and Europe. “Every day in the UK alone, nearly 200 people develop the severe, blinding forms of AMD. There are two main forms of AMD – a ‘dry’ type and the ‘wet’ one. Wet AMD has nothing to do with watery eyes but is so-called because abnormal blood vessels grow under the centre of the retina (the nerve tissue that lines the back of the eye). These blood vessels leak fluid and bleed easily, and this can cause severe visual loss because it is such a sensitive area.”
Keane says that, until about 10 years ago, there was no effective treatment for the wet form of AMD, but now it can be treated with regular injections of drugs such as Eylea or Lucentis into the eye. They block the growth of new blood vessels and reduce the leakage of fluid from existing vessels. This improves sight substantially in about a third of patients and prevents further worsening of vision in about 95% of cases. However, the effects of the drugs last only one to two months, so people need frequent injections over long periods of time.
Andrew Lotery, a professor of ophthalmology at the University of Southampton, says everyone over 50 should at least be aware that if they have a loss of vision in one eye that is not corrected when they put on their glasses, then it could be rapidly developing wet AMD.
“You should be seen in hospital within a week because scarring develops if wet AMD is left untreated.” Optometrists and ophthalmic practitioners (doctors trained to examine eyes) can look for early signs of macular degeneration and will refer on urgently if they are concerned. In the past, diagnosis relied on a slit-lamp examination – a contact lens put on the eye and observed through a microscope looking for thickening of the retina – and a fluorescein angiogram (FA), which involves an injection into a vein in the arm to highlight blood vessels in the eye. But “FA makes lots of people sick and occasionally causes severe allergic reactions,” says Lotery.
Happily, there is an alternative now. “The initial diagnosis of wet AMD, and the need for follow-up treatments, is determined with a form of retinal imaging called optical coherence tomography (OCT),” says Keane. OCT is a relatively new form of medical imaging, having been around since 1991. It is analogous to ultrasound except that it measures the reflection of light waves, rather than sound. Most people with known retinal disease have an OCT scan at every hospital eye clinic appointment and get offered more injections into the eye if there are signs of “fluid”.
Lotery says the price of OCT machines are coming down all the time although they still cost around £50,000 each. There are also now handheld OCTs, which some believe will make detecting eye disease as “easy as scanning a barcode”, but Lotery urges caution: “Don’t rush out to buy one. You still need a trained health professional to interpret the results – it’s easy to misinterpret them.”
Machines are also being trained in diagnostic techniques. Google’s DeepMind has used data from thousands of OCT scans to develop an algorithm that can diagnose wet AMD at least as quickly and effectively as eye specialists can. A partnership with Moorfields and the NHS will shortly publish more detailed results.
AMD develops as the eye ages – and Blakeney says other risk factors include a family history of AMD, smoking, excessive exposure to UV light and, possibly, to screens. Maintaining a normal weight may be protective and there is probably a role for foods that contain dietary pigments, such as blueberries and peppers. “There is no good evidence that the general population should take supplements, but if you already have AMD in one eye, it may be advisable.”
Dry AMD is less severe than wet, progresses over years rather than months and causes more gradual loss of central vision. “Unfortunately, there is no effective treatment for dry AMD, although there are many clinical trials under way,” says Keane.
The exciting developments in diagnosis and treatment of wet AMD have come too late for Lorna Blakeney. She is one of the 360,000 people in the UK who are registered as blind or visually impaired. Six years after her initial diagnosis, Lorna noticed that the venetian blinds in her bathroom window looked wiggly in her remaining sighted eye. “This time, I had injections of the drug Lucentis into my eye. I thought it would be a magic bullet; it is for many, but it wasn’t for me. Gradually, I lost the sight in the eye and I’m now registered as severely sight impaired, with only a bit of peripheral vision left.”
“There is life after AMD. I manage pretty well, with every gadget known to man.” She uses software on her phone and a tablet with “speaking” icons, has voice recognition software to dictate emails, a talking watch, clock, kitchen scales, measuring jug and microwave. One gadget rests on the edge of a mug and beeps twice; once for the water and once for the milk, to make a perfect cup of tea without spillages. Another clips on to her glasses and scans and speaks the writing on food labels in the supermarket. Lorna says all these aids are enormously helpful, but they don’t come cheap and most are not subsidised.
“If I go out on my own, I have a symbol cane to let other people know that I can’t see them although I have enough peripheral vision that I can move around without bumping into things. Not being able to read is biggest nuisance. One very posh British restaurant we went to had the French ‘mesdames’ and ‘messieurs’ in pale grey letters on a pale-green sign. I didn’t stand a chance.”
June 1st 2018
Scientists create the first 3D-printed human corneas
Newcastle University researchers have devised a groundbreaking experimental technique that could help millions on the corneal transplant waiting list. By using a simple 3D bio-printer, Professor of Tissue Engineering Che Connon and his team of scientists were able to combine healthy corneal stem cells with collagen and alginate (a type of sugar sometimes used in tissue regeneration) to create 'bio-ink' -- a printable solution that enabled them to reproduce the shape of a human cornea in just 10 minutes.
The cornea has a significant role in helping us focus and barricading our eyes against dirt and bacteria. However, since it's located on the outermost layer of the eye, it's also pretty vulnerable to injury. Worldwide, approximately 10 million people risk corneal blindness due to infectious disorders like trachoma, but there's a dearth of readily available transplants. Because Connon's 3D-printed corneas utilize stem cells, corneal replicas could potentially provide a limitless supply of much-needed transplants.
"Our unique gel - a combination of alginate and collagen - keeps the stem cells alive whilst producing a material which is stiff enough to hold its shape but soft enough to be squeezed out the nozzle of a 3D printer," Connon said.
Before printing the corneal replicas, researchers scanned patients' eyes to ascertain the necessary dimensions and coordinates. While it's likely patients will have to wait "several years" before these 3D-printed corneas are available in an official capacity, they still represent incredible hope for those with more severe corneal-related impairments.
Sep 4th 2016
Stanford researchers, funded in part by the National Eye Institute and the Glaucoma Research Foundation, make discovery that may lead to help for glaucoma patients who have lost vision. Study points toward potential regenerative therapies for damaged cells.
New research by Andrew Huberman, PhD, associate professor of neurobiology at Stanford University, has taken a novel approach to the study of nerve regeneration in glaucoma. In a study published in the scientific journal Nature Neuroscience, Dr. Huberman describes conditioning injured optic nerve cells to regenerate. Blind mice treated with this approach regained partial eyesight—a surprising discovery that has significant implications for neurodegenerative diseases like glaucoma.
In glaucoma, the retinal ganglion cells—which collect visual information and send it to the brain—suffer the most damage. Dr. Huberman and his colleagues have been exploring ways to help these cells regrow and reconnect to the brain. The researchers adopted a combined approach that uses both genetic and visual stimulation to enhance neural activity. They activated common growth mechanism in cells, called the mTOR signaling pathway, in the severed retinal ganglions of mice and also repeatedly exposed the damaged eye to high-contrast oscillating black-and-white images. The researchers discovered that this regimen was able to trigger the once-injured retinal cells to regrow optic nerve fibers along damaged pathways to the brain, giving the mice limited eyesight.
Huberman’s research demonstrated for the first time that repaired retinal ganglion cells, when treated with combination therapy, have the capacity to re-establish connections to the brain to restore vision. This is just the beginning: Ocular repair and strategies to correct diseases like glaucoma may well lead to treatments for other causes of blindness and for neurodegenerative diseases that affect other parts of the body and brain, offering hope to millions of afflicted people worldwide.
The study, funded in part by the San Francisco-based Glaucoma Research Foundation, is part of the National Institutes of Health’s “audacious goals” in vision research, which aims to develop new treatments for major eye diseases, including glaucoma, by 2022. “What they have shown in an animal model is that maybe we can restore vision by reconnecting the nerve cells that are damaged,” said Thomas M. Brunner, President and CEO of the Glaucoma Research Foundation. “Their research shows that there may be promise for people, where we think vision is permanently gone, to restore it.”
Andrew Iwach, MD, the executive director of the Glaucoma Center of San Francisco and a professor of ophthalmology at UC San Francisco, said the new research highlighted an opportunity for doctors to take a more active role in treatment, instead of just prevention. “This may help us open another area of exploration for research, not only to play defense and protect what’s left, but also go on the offense to help patients,” Dr. Iwach said.
I have just discovered that that some types of decongestant sprays carry a glaucoma warning read the small print.
March 12th 2016 News
A pioneering procedure to regenerate the eye has successfully treated children with cataracts in China.
More than half of all cases of blindness are caused by cataracts - the clouding of the eye's lens.
An implanted lens is normally needed to restore sight, but the operation described in Nature activated stem cells in the eye to grow a new one.
Experts describe the breakthrough as one of the finest achievements in regenerative medicine.
The lens sits just behind the pupil and focuses light on to the retina.
About 20 million people are blind because of cataracts, which become more common with age - although some children are born with them.
Conventional treatment uses ultrasound to soften and break up the lens, which is then flushed out.
An artificial intraocular lens must then be implanted back into the eye, but this can result in complications, particularly in children.
Image copyright SPL Image caption Close up of a cataract clouding the normally transparent lens
The technique developed by scientists at the Sun Yat-sen University and the University of California, San Diego removes the cloudy cataract from inside the lens via a tiny incision.
Crucially it leaves the outer surface - called the lens capsule - intact.
This structure is lined with lens epithelial stem cells, which normally repair damage.
The scientists hoped that preserving them would regenerate the lens.
The team reported that tests on rabbits and monkeys were successful, so the approach was trialled in 12 children.
Within eight months the regenerated lens was back to the same size as normal.
The study is one of the finest achievements in the field of regenerative medicine until nowDr Dusko Ilic, King's College London
Dr Kang Zhang, one of the researchers, told the BBC News website: "This is the first time an entire lens has been regenerated. The children were operated on in China and they continue to be doing very well with normal vision."
It also showed a dramatically lower complication rate "by almost every measure, supporting the superiority of the treatment".
However, he says larger trials are needed before it should become the standard treatment for patients.
The procedure was tried in children because their lens epithelial stem cells are more youthful and more able to regenerate than in older patients.
Yet the overwhelming majority of cataracts are in the elderly.
Dr Zhang says tests have already started on older pairs of eyes and says the early research "looks very encouraging".
Commenting on the findings, Prof Robin Ali from the UCL Institute of Ophthalmology, said the work was "stunning".
He told the BBC News website: "This new approach offers greatly improved prospects for the treatment of paediatric cataracts as it results in regeneration of a normal lens that grows naturally."
He said getting similar results in adults "is likely to be more difficult to achieve" but could "have a major impact".
"It might be superior to the artificial lenses that are currently implanted, as the natural lenses should be able to accommodate looking at different distances more effectively," he added.
Dr Dusko Ilic, a reader in stem cell science at King's College London, said: "The study is one of the finest achievements in the field of regenerative medicine until now.
"It is science at its best."
Dr Zhang believes that targeting stem cells already sitting in the eye could have "great potential" for treating a wide range of diseases from macular degeneration to glaucoma.
A separate study by Osaka University in Japan and Cardiff University, used stem cells to mirror the development of the eye.
They were able to produce a range of specialised eye tissues including those that make the cornea, conjunctiva, lens and retina.
The findings, also published in Nature, showed the lab-grown tissues could restore sight to rabbits with corneal blindness.
One of the researchers, Prof Andrew Quantock, said: "Our work not only holds potential for developing cells for treatment of other areas of the eye, but could set the stage for future human clinical trials of anterior eye transplantation to restore visual function."
Glaucoma is a condition affecting your eyes that if not treated will blind you.
People don't often realise their sight is being damaged because the first part of the eye to be affected is the outer field of vision (peripheral vision). there are usually no noticeable symptoms because the condition develops very slowly, vision is lost from the outer rim of the eye, slowly working inwards towards the center.
You want to get your eyes tested at least every 12 months by someone who also measures the pressure of the fluid in your eyeballs, if he considers this to be too high he will recommend you go to see your doctor and he will give you a backup letter explaining the situation. The doctor will then refer you to a glaucoma specialist doctor.
There are four different types of glaucoma listed here.
Acute angle-closure glaucoma
This type of glaucoma develops very rapidly and you will experience severe pain, possibly a headache and strange disturbances to your vision many people feel nauseous or actually vomit these symptoms can last one or two hours but each attack damages your vision so the best advice I can give you is to get yourself down to the hospital as soon as you possibly can even if it's the middle of the night.
May be caused by eye injuries and certain treatments, such as medication or operations, but can also be caused by other conditions such as inflammation of the middle layer of the eye the medical name for this is uveitis, this is why you need to see a medical specialist without delay to check your secondary glaucoma situation,some of these conditions are very complicated and the symptoms can be very confusing so it's essential that you get the best optical care that you possibly can.
Parents should pay special attention to the eyes of their young children, if you see anything peculiar about the condition of their eyes, such as abnormal movements, watery eyes that are sensitive to light or a tendency to squint you must take them straight away to your family doctor or optometrist.
There are many research organisations that are desperately trying to find better treatments and maybe a cure for these terrible conditions, we have hopes for treatments with stem cells or alternatively with nano particles, so we hope and pray that we shall soon see a result that will bring a cure.
Latest news March 9th 2016
Scientists have demonstrated a method for generating several key types of eye tissue from human stem cells in a way that mirrors whole eye development.
When transplanted to an animal model of corneal blindness, these tissues are shown to repair the front of the eye and restore vision, which scientists say could pave the way for human clinical trials of anterior eye transplantation to restore lost or damaged vision. A collaborative team comprising researchers from Cardiff University and Osaka University in Japan describe their findings today in Nature. The eye is composed of highly specialized tissues that are derived from a variety of cell lineages during development. Previous studies have demonstrated that particular cell types, such as those that constitute the retina or cornea, can be created in the laboratory from pluripotent stem cells. However, these studies do not represent the complexity of whole eye development. This latest study reports the generation of multiple cell lineages of the eye, including the lens, cornea, and conjunctiva, using human induced pluripotent stem cells. The scientists have been able to show that the corneal epithelial cells can be cultivated and transplanted onto the eyes of rabbits with experimentally induced blindness to surgically repair the front of the eye. Study co-author Professor Andrew Quantock, from Cardiff University's School of Optometry and Vision Sciences, said: "This research shows that various types of human stem cells are able to take on the characteristics of the cornea, lens and retina. "Importantly, it demonstrates that one cell type -- the corneal epithelium -- could be further grown in the lab and then transplanted on to a rabbit's eye where it was functional, achieving recovered vision. "Our work not only holds potential for developing cells for treatment of other areas of the eye, but could set the stage for future human clinical trials of anterior eye transplantation to restore visual function." Around 4000 corneal grafts are performed by the NHS annually, which rely on human organ donation. The research was funded by the Japanese government's Agency for Medical Research and Development.
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