Eye Implant breakthrough

By Andrew Hough
Eye implant breakthrough: scientific advances towards a blindness cures
An eye test is the only way to diagnose glaucoma, the leading cause of blindness in Britain.

* Stem cells grown on contact lenses could be a cure for a common cause of blindness, claim scientists. Australian researchers said that the world breakthrough could "dramatically improve" the sight of patients with damage to their cornea – the clear outer shell of the eye – caused by disease or injury.

The research team removed tissue with regenerative stem cells from patients' own eyes and then multiplied them in the laboratory on the surface of a contact lens. This was then placed back onto the damaged cornea for 10 days, during which the cells, which can turn into any other sort of cell, were able to recolonise and "patch" the damaged eye surface. Within weeks the patients saw dramatic improvements in their vision. If early findings bear out then the treatment could be affective for thousands of patients in Britain and is so cheap it could be used for millions more in the Third World.

* Artificial corneas grown in the laboratory were transplanted into patient's eyes for the first time in an operation, scientists reported. The new technique involved growing human tissue or collagen in the laboratory and then shaping it using a contact lens mould.

Damaged and scarred tissue from the front of the eye is then removed and the "biosynthetic" replacement is stitched in its place. Eventually existing cells and nerves in the eye grow over the artificial cornea incorporating it fully into the eye.

* Eye cells that are sensitive to light were produced from skin in a breakthrough that could eventually lead to treatments for blindness, scientists reported in August. Researchers genetically “reprogrammed” human skin cells to possess the same properties as those that make up the retina.

The process involved first turning them into pluripotent stem (IPS) cells, which have the potential to develop into virtually every kind of tissue in the body. By exposing the IPS cells to a specific cocktail of chemicals, the scientists then caused them to grow into partially developed retina cells – the light-sensitive cells at the back of the eye which transmit nerve signals to the brain.

* Patients who were left blinded after chemical accidents have had their sight restored using corneas grown from their own stem cells, scientists claimed in June. In the largest study of its kind, Italian researchers said they restored the sight of patients left blinded or suffered severely impaired vision, after suffering chemical burns.

Experts said the study, undertaken between 1998 and 2007, offers new hope to the thousands of people who suffer chemical burns on their corneas from heavy-duty cleansers or other substances at work or at home. The research is also being hailed as a key breakthrough in scientific regeneration that could give hope to other patients with otherwise irreversible eyesight.

* Also in June, a new study suggested a simple way to stop you eyesight deterioriating - drinking red wine. Researchers have found that a substance found in grapes and other fruits could protect blood vessels in the eye being damaged by old age. It is effective because the compound, known as resveratrol, stops the blood vessels from being damaged.

The substance, which has been linked to anti-ageing and cancer protection in the past, is believed to work because it protects against abnormal angiogenesis – the formation of damaged or mutated blood vessels. This condition is linked to cancer, heart disease and eye diseases such as age-related macular degeneration. In the study, reported in the New England Journal of Medicine, researchers successfully extracted adult stem cells from healthy eye tissue before growing additional stem cells that were placed over damaged eye tissue.

* Gene therapy was used by American scientists to improve the vision of children with hereditary blindness. US doctors treating 12 patients with a rare genetic eye disorder were able to significantly improve vision in the youngest, according to medical journal The Lancet. The research, which builds on work carried out by doctors at London's Moorfields Eye Hospital, focused on Leber's congenital amaurosis (LCA), a disorder which causes gradual deterioration in vision and can lead to blindness by the time the patient is 20. It occurs when faulty genes, called RPE65, stop the layer of cells at the back of the eye working and affects approximately one in 80,000 people. It is responsible for one in 10 severe sight disorders in children.

* Scientists cured colour blindness in monkeys, in what some were signalling has new hope for millions of sufferers of the condition. Researchers reported last September that they cured the animals using a treatment called gene therapy. A harmless virus which delivers corrective genes to the retina was injected into the eyes of two squirrel monkeys, Dalton and Sam, who had been colour blind since birth. Within weeks a protein produced by the corrective genes allowed both monkeys to make out reds and greens for the first time. They can still see the colours two years later. The breakthrough could also have implications for other damaging genetic eye defects, including those which can cause blindness, after researchers proved for the first time that the brain can “rewire” itself to see things it has never been able to before.

* A new eye drop treatment was offered to help preserve the sight of thousands of people at risk of going blind due to glaucoma, scientists reported. The drops were first of their kind that avoid unpleasant side effects which deter up to a third of patients from continuing their treatment.

Many patients simply refuse to apply the drops because of the discomfort, thereby putting themselves at risk of vision loss. Regular use of the eye drops can keep the condition under control for a patient's life time. Without them, a patient can go blind in five to 10 years. When the disease becomes too advanced the only remedy is surgery, which is risky and may itself result in blindness.

Radiation and Lucentis Combined to Treat Macular Degeneration

by Randall V. Wong M.D

External beam radiation and Lucentis may be combined to treat wet macular degeneration. The results showed the treatment may be very safe and, when combined with anti-VEGF injections such as Lucentis, may decrease the need for frequently repeated injections.

Neovascularization, the growth of abnormal blood vessels, underneath the macular defines “wet macular degeneration.”
Radiation Kills Cells

Radiation treatments have been used in and around the eye to treat tumors. Radiation, in this case, halts the replication of cells. In the case of tumors, the lesions can no longer grow. So too, with neovascularization, new growth is inhibited. This is not the first study that has investigated the use of radiation for wet macular degeneration, but this is one of first trials combining external beam radiation with Lucentis.

Side Effects of Radiation to the Eye

Radiation can be toxic to the eye. It can cause cataracts, damage to the optic nerve and retina. It may also damage the lacrimal (produces tears to the eye) system and cause dry eye.

The investigators were able to dose and administer the radiation safely, seemingly able to avoid the usual complications of external beam radiation.
Treatment Required Fewer Injections of Lucentis

The gold standard for treating wet macular degeneration is now injections with either Lucentis or Avastin. The injections, however, need to be repeated as often as monthly. While highly successful, the need for repeated treatment requires a lot of trips to the office and can be expensive.

The study combined the use of the popular anti-VEGF agent, Lucentis (ranibizumab). The design of the trial required 2 initial injections during the first month of treatment.

52% of patients did not require additional injections for the 12 month study period (they only had 2!).

Also noteworthy, most patients stabilized and actually improved their vision.

What Does This Mean? This is not an approved treatment. It is in no way a true “study,” but this small trial still has some merits. It provides us with a small amount of evidence that alternative treatments using radiation may be useful.

First, recall that anti-VEGF injections, such as Lucentis or Avastin, now standard therapy for wet macular degeneration, were developed for chemotherapy against several types of cancers. The discovery that this improved patients with macular degeneration was coincidental.

For instance, patients receiving chemotherapy for colon cancer started noting improvement in their vision. Evidently, these patients had both cancer and wet macular degeneration.

External beam radiation has long been used for many types of cancer treatments.

In both cases, agents that halt rapidly dividing (i.e. growing) tissues should be effective in both the cancer treatment and the eye disease. The radiation stymies cell replication and the Lucentis (anti-VEGF) inhibits grow of new blood vessels. In the case of cancer, a tumor can not enlarge without blood supply.

So, it makes sense that this may work.

Lastly, this really underscores the need for treatments that do not need to be repeated so frequently, such is the case with Lucentis and Avastin. Right now, most doctors inject as frequently as every 4-6 weeks! Drug delivery systems designed to release drug over an extended period may aid this as well.