StemCell Therapy

Ophthalmology is the branch of medicine that deals with the anatomy, physiology and diseases of the eye.[1] An ophthalmologist is a specialist in medical and surgical eye problems. Since ophthalmologists perform operations on eyes, they are both surgical and medical specialists. A multitude of diseases and conditions can be diagnosed from the eye.[2]

The word ophthalmology comes from the Greek roots , ophthalmos, i.e., "eye" and -o, -logia, i.e., "study of, discourse";[3][4] ophthalmology literally means "the science of eyes". As a discipline, it applies to animal eyes also, since the differences from human practice are surprisingly minor and are related mainly to differences in anatomy or prevalence, not differences in disease processes.[citation needed]

The Indian surgeon Sushruta wrote Sushruta Samhita in Sanskrit in about 800 BC which describes 76 ocular diseases (of these 51 surgical) as well as several ophthalmological surgical instruments and techniques.[5][6] His description of cataract surgery was more akin to extracapsular lens extraction than to couching.[7] He has been described as the first cataract surgeon.[8][9]

The pre-Hippocratics largely based their anatomical conceptions of the eye on speculation, rather than empiricism.[10] They recognized the sclera and transparent cornea running flushly as the outer coating of the eye, with an inner layer with pupil, and a fluid at the centre. It was believed, by Alcamaeon and others, that this fluid was the medium of vision and flowed from the eye to the brain by a tube. Aristotle advanced such ideas with empiricism. He dissected the eyes of animals, and discovering three layers (not two), found that the fluid was of a constant consistency with the lens forming (or congealing) after death, and the surrounding layers were seen to be juxtaposed. He and his contemporaries further put forth the existence of three tubes leading from the eye, not one. One tube from each eye met within the skull.

Rufus of Ephesus recognised a more modern eye, with conjunctiva, extending as a fourth epithelial layer over the eye.[11] Rufus was the first to recognise a two-chambered eye, with one chamber from cornea to lens (filled with water), the other from lens to retina (filled with an egg white-like substance). The Greek physician Galen remedied some mistakes including the curvature of the cornea and lens, the nature of the optic nerve, and the existence of a posterior chamber.

Though this model was a roughly correct modern model of the eye, it contained errors. Still, it was not advanced upon again until after Vesalius. A ciliary body was then discovered and the sclera, retina, choroid, and cornea were seen to meet at the same point. The two chambers were seen to hold the same fluid, as well as the lens being attached to the choroid. Galen continued the notion of a central canal, but he dissected the optic nerve and saw that it was solid. He mistakenly counted seven optical muscles, one too many. He also knew of the tear ducts.

Medieval Islamic Arabic and Persian scientists (unlike their classical predecessors) considered it normal to combine theory and practice, including the crafting of precise instruments, and therefore found it natural to combine the study of the eye with the practical application of that knowledge.[12]

Ibn al-Haytham (Alhazen), an Arab scientist with Islamic beliefs, wrote extensively on optics and the anatomy of the eye in his Book of Optics (1021).

Ibn al-Nafis, an Arabic native of Damascus, wrote a large textbook, The Polished Book on Experimental Ophthalmology, divided into two parts, On the Theory of Ophthalmology and Simple and Compounded Ophthalmic Drugs.[13]

In the 17th and 18th centuries, hand lenses were used by Malpighi, and microscopes by van Leeuwenhoek, preparations for fixing the eye for study by Ruysch, and later the freezing of the eye by Petit. This allowed for detailed study of the eye and an advanced model. Some mistakes persisted, such as: why the pupil changed size (seen to be vessels of the iris filling with blood), the existence of the posterior chamber, and of course the nature of the retina. In 1722, van Leeuwenhoek noted the existence of rods and cones,[citation needed] though they were not properly discovered until Gottfried Reinhold Treviranus in 1834 by use of a microscope.

Visit link:
Ophthalmology - Wikipedia, the free encyclopedia

The Wilmer Eye Institute at Johns Hopkins, founded in 1925, is an internationally-renowned eye institution that specializes in the diagnosis and management of complex medical and surgical eye disease; and serves as a preeminent provider of routine eye care and refractive, optical, cosmetic, and eye trauma services for the Mid-Atlantic region. Wilmer is also recognized as a national leader in research and in the training of medical students, residents, fellows, and ophthalmic technicians. As the largest department of ophthalmology in the United States, the Wilmer Eye Institute has earned recognition for bringing together ophthalmologists and optometrists consistently regarded as being amongthe finest in the field.

On this website, we provide an overview of the Wilmer Eye Institute's various departments, care providers, and research activities. You will also find information on making appointments at Wilmer, along with directions to our multiple service locations.

Were connecting to improve your care. Johns Hopkins Medicine is implementing a new electronic medical record system that will help you be an active partner in your health care and improve the high-quality care you already receive. We appreciate your patience as we put this new system in place. For more information, visit http://www.hopkinsmedicine.org/myrecord.

If you need general assistance, please call the Wilmer Call Center at 410-955-5080, or toll free at 1-800-21JOHNS (1-800-215-6467)

Read more:
Wilmer Eye Institute - Johns Hopkins - Baltimore, Maryland

Written by Lois Alcosser Saturday, 26 May 2012 07:00

Though macular degeneration is rarely discussed as a health topic, it is a fearful possibility, especially as people age. That could account for the standing-room-only audience when Dr. Jeffrey Oberman, chief of opthalmology at Norwalk Hospital, spoke recently at the Greens at Cannondale. He explained in detail the causes, symptoms and latest advances in the treatment of macular degeneration.

The macula, he explained, is at the back wall of the eye. It is only 1% of the eyes physiology, but responsible for 90% of vision problems, and is the most common cause of visual loss in the developed world.

Painless and progressive, there are two forms of macular degeneration: dry and wet. The most frequent, the dry form, occurs when the light-sensitive cells in the macula slowly break down, blurring the central vision of the affected eye. Reading becomes difficult, so does recognizing faces. In the more severe, wet form, abnormal blood vessels form and leak into the macula area of the eye. Straight lines appear wavy, and there is a blind spot in the center of the eye.

Before there are any symptoms or vision loss, yellowish spots, called drusen, can be detected with a comprehensive eye exam, which is why it is so important to have regular eye examinations. The dry form can turn into the wet form, which is much more likely to affect vision, and is much more difficult to treat.

Risk factors for macular degeneration include age, smoking, obesity, family history and lifestyle. Dry degeneration can be treated with antioxidants, which are only helpful in the intermediate stage. A formulation called AREDS, consisting of Vitamins A, C, E, zinc and copper, is recommended. Something as simple as wearing sunglasses is helpful, to block out ultraviolet light.

The wet form of macular degeneration has been treated with lasers, photodynamic therapy and injections, but none is a cure. Injections, however, can potentially improve vision and stabilize the condition. Though these injections are into the eye, they are relatively painless. They are usually done monthly or bimonthly. Lucentis has stabilized degeneration 95% and improved acuity 34%. The problem is, it costs around $2,000 per injection. A much less expensive injection, Avastin, ($75 per dose) can slow the rate of progression and may cause some improvement.

There are many studies underway to find better, more affordable ways to improve treatment. The use of stem cells to create a healthy macula has proven successful in mice. But considering the fact there are 1.4 million fibers from the eye to the brain to create sight, this is clearly a complex and daunting challenge.

Dr. Oberman expressed great hope in further research. Meanwhile, be sure and get your eyes examined regularly.

Follow this link:
Macular degeneration: Causes, symptoms, cures

Stem cells reverse blindness caused by burns

By ALICIA CHANG (AP) – 1 day ago

LOS ANGELES — Dozens of people who were blinded or otherwise suffered severe eye damage when they were splashed with caustic chemicals had their sight restored with transplants of their own stem cells — a stunning success for the burgeoning cell-therapy field, Italian researchers reported Wednesday.

The treatment worked completely in 82 of 107 eyes and partially in 14 others, with benefits lasting up to a decade so far. One man whose eyes were severely damaged more than 60 years ago now has near-normal vision.

"This is a roaring success," said ophthalmologist Dr. Ivan Schwab of the University of California, Davis, who had no role in the study — the longest and largest of its kind.

Stem cell transplants offer hope to the thousands of people worldwide every year who suffer chemical burns on their corneas from heavy-duty cleansers or other substances at work or at home.

The approach would not help people with damage to the optic nerve or macular degeneration, which involves the retina. Nor would it work in people who are completely blind in both eyes, because doctors need at least some healthy tissue that they can transplant.

In the study, published online by the New England Journal of Medicine, researchers took a small number of stem cells from a patient's healthy eye, multiplied them in the lab and placed them into the burned eye, where they were able to grow new corneal tissue to replace what had been damaged. Since the stem cells are from their own bodies, the patients do not need to take anti-rejection drugs.

Adult stem cells have been used for decades to cure blood cancers such as leukemia and diseases like sickle cell anemia. But fixing a problem like damaged eyes is a relatively new use. Researchers have been studying cell therapy for a host of other diseases, including diabetes and heart failure, with limited success.

Adult stem cells, which are found around the body, are different from embryonic stem cells, which come from human embryos and have stirred ethical concerns because removing the cells requires destroying the embryos.

Currently, people with eye burns can get an artificial cornea, a procedure that carries such complications as infection and glaucoma, or they can receive a transplant using stem cells from a cadaver, but that requires taking drugs to prevent rejection.

The Italian study involved 106 patients treated between 1998 and 2007. Most had extensive damage in one eye, and some had such limited vision that they could only sense light, count fingers or perceive hand motions. Many had been blind for years and had had unsuccessful operations to restore their vision.

The cells were taken from the limbus, the rim around the cornea, the clear window that covers the colored part of the eye. In a normal eye, stem cells in the limbus are like factories, churning out new cells to replace dead corneal cells. When an injury kills off the stem cells, scar tissue forms over the cornea, clouding vision and causing blindness.

In the Italian study, the doctors removed scar tissue over the cornea and glued the laboratory-grown stem cells over the injured eye. In cases where both eyes were damaged by burns, cells were taken from an unaffected part of the limbus.

Researchers followed the patients for an average of three years and some as long as a decade. More than three-quarters regained sight after the transplant. An additional 13 percent were considered a partial success. Though their vision improved, they still had some cloudiness in the cornea.

Patients with superficial damage were able to see within one to two months. Those with more extensive injuries took several months longer.

"They were incredibly happy. Some said it was a miracle," said one of the study leaders, Graziella Pellegrini of the University of Modena's Center for Regenerative Medicine in Italy. "It was not a miracle. It was simply a technique."

The study was partly funded by the Italian government.

Researchers in the United States have been testing a different way to use self-supplied stem cells, but that work is preliminary.

One of the successful transplants in the Italian study involved a man who had severe damage in both eyes as a result of a chemical burn in 1948. Doctors grafted stem cells from a small section of his left eye to both eyes. His vision is now close to normal.

In 2008, there were 2,850 work-related chemical burns to the eyes in the United States, according to the Bureau of Labor Statistics.

Schwab of UC Davis said stem cell transplants would not help those blinded by burns in both eyes because doctors need stem cells to do the procedure.

"I don't want to give the false hope that this will answer their prayers," he said.

Dr. Sophie Deng, a cornea expert at the UCLA's Jules Stein Eye Institute, said the biggest advantage was that the Italian doctors were able to expand the number of stem cells in the lab. This technique is less invasive than taking a large tissue sample from the eye and lowers the chance of an eye injury.

"The key is whether you can find a good stem cell population and expand it," she said.

___

Online:

New England Journal: http://www.nejm.org