How Do You Solve a Problem Like Glaucoma?
|
Among one of the newer ideas for glaucoma control is the concept of stem cell injections into the eye to halt or reverse this insidious disease. Researchers have already reported success in rat experimentation and hope to start trials in humans within the next five years. The method involves harvesting stem cells from the patient’s own bone marrow and creating a solution that enables the substance to be injected into the back of their eye. This prevents further degeneration of the optic nerve and retina. This method can also transform the tissues into new optic nerve cells, reversing damage and improving eyesight.
Professor Keith Martin, a neuroscientist at Cambridge University, U.K., said, "Finding treatments to reverse blindness is no longer in the realm of science fiction. We have concentrated on glaucoma because it is so common, but there are quite a few diseases that affect the optic nerve such as inflammatory diseases, so it can be used in those cases as well." The team has had success in halting glaucoma in rats and reversing it to some extent. They are still working on the ultimate objective; how to cure blindness.
There are 300,000 people in England diagnosed with glaucoma. However, the total number of sufferers is said to be double that size and the majority of victims are over 40 years of age. The condition is described as the cause of damage to the optic nerve fibers and retinal tissue preventing normal transmission of signals to the brain. Loss of sight from the narrowing of the visual fields due to the increased intraocular pressure are the expected complications.
Professor Martin feels that this new technique would be of special benefit to two groups of glaucoma patients: those diagnosed with advanced glaucoma and those who developed it early in life. Existing treatment that lowers the ocular pressure works well for most people, but as a preventative measure was ineffective with advanced glaucoma. Dr. Martin also added that lowering ocular pressure alone could not stave off the effects of glaucoma over years or decades. Dr. Dolores Conroy, research officer for
Fight For Sight says, “Advances in stem cell technology are likely to revolutionize treatments of diseases like glaucoma. We must invest in this research field now so that treatments to save and restore the sight of millions of people are available in the future."
To add to glaucoma treatment concerns, the 2010 issue of The Journal of Ophthalmology reported a study that states glaucoma patients who have lost some or most of their sight are not using their glaucoma medication eye drops properly. This leads to a waste of costly eye drops and possible bottle contamination. In a study of 204 glaucoma patients, all of whom were visually impaired and had already used eye drops for more than six months, the participants were videotaped while trying to administer a single drop into their worst seeing eye.
A survey was completed about their use of the eye drops. It was found that only 71 percent were able to get a drop into the eye. Only 39 percent did so without touching the bottle to the surface of the eye. Of the 142 patients who said they did not touch the eye with the bottle, 24 percent actually did, according to the videotape evidence. Some were getting multiple drops in the eye instead of the one drop they were instructed to instill. Also, people over the age of 70 not surprisingly experienced more trouble than the younger participants. The authors recommended that more thought be given to the ability of a person to self administer eye drops before glaucoma eye drops are prescribed. They also recommended that better ways of instilling eye drops be found.
Taiwanese researchers have discovered yet another dilemma for glaucoma victims. They found that people with glaucoma are more likely to have additional serious health problems. The conclusion is based on a nationwide study in Taiwan that compared the medical records of 76,673 people with open angle glaucoma (OAG) with the records of 230,019 people without OAG, matched for age, gender and other factors. Results showed that more than half of the people with glaucoma had elevated blood pressure and more than 30% had either diabetes or high levels of unhealthy fats in the blood.
Overall, the glaucoma patients had at least a 3% higher prevalence of these diseases plus strokes, liver disease and ulcers. One of the causes of glaucoma is thought to be as a result from abnormalities in the blood vessels and circulation that nourishes the optic nerve, the eyes and the brain as well as the remainder of the body parts. These abnormalities can also be linked to the other diseases found in the glaucoma patients. The result of the Taiwan study appears on the American Academy of Ophthalmology website.
An advance in the attempt to control intraocular pressure was announced by Allergan in September of 2010 as the FDA approved Lumigan 0.01% treatment for OAG or ocular hypertension. Compared to the existing Lumigan 0.03%, the change is a reformulation that, in a three month patient study, lowered intraocular pressure (IOP) up to 7mm of mercury from a baseline (quite a significant drop in pressure), and this with only one third the exposures to the active drug, bimatoprost. A lower drug exposure often results in fewer complications from the drug. However, Allergan's press release did not mention such reductions for the new formula. It is mentioned that the side effects from bimatoprost may include conjunctival hyperemia, eyelash growth and increased pigmentation of the iris, the eyelids and eyelashes.
Results of a different sort were reported in the July 2010 issue of
The Journal of Ophthalmology, authored by researchers from the University of Toronto. They state that a "head up" sleeping position may keep IOP from spiking at night. For those who have high pressure it is suggested that they try sleeping with an extra pillow under the head. In a small study of 17 glaucoma patients with controlled IOP and new disc hemorrhage, researchers compared their IOP at regular intervals while asleep and lying flat and while asleep and lying in a 30 degree head up position. They discovered a reduction in the IOP of 20 percent or more in 35 percent of the subjects, with 16 of the 17 patients having lower IOP in this position than in the lying-flat position.
Measuring and monitoring changes in eye pressure has a new twist via a European contact lens called Triggerfish. A Swiss company called Sensimed uses sensors that measure changes in corneal curvature. A similar procedure was covered in an
EyeCare Professional article which appeared in our September, 2008 issue titled "Electronic Contact Lenses." The article described a contact lens with circuit sensors that responded to pressure changes. The new concept utilizes sensors that respond to corneal curvature changes due to IOP increases. This is accomplished by means of a chip that transmits the gauges readings wirelessly to an external receiver that is worn around the patient's neck.
However, researchers believe that improvement is necessary to develop a contact lens chip circuitry that should be completely transparent. This technology does hold significant promise however. Normally, an eye doctor would take intraocular pressure measurements during a daytime appointment. Pressure tends to be at its lowest then, so that the overall picture of the patient's condition is incomplete and doesn't reflect the pressure spikes that may be occurring at other times during the day or night. The contact lens chip transmits the readings throughout the day which would give the doctor much more detailed information on the patient. The device may be able to monitor high risk people who do not as yet have glaucoma. This would possibly catch the disease in the early stages so treatment can commence promptly to minimize vision loss. Currently, the new device is available only in Europe.
Green tea lovers will be pleased to learn that recent documentation reports how the eye's lens, retina and other tissues absorb antioxidants which are found in green tea. Until now, it was unclear whether green tea elements really did make their way from the digestive system to the eye tissues. A study was conducted in which laboratory rats drank green teas and were found to have significant amounts of individual antioxidants called catechins in their eyes. Researchers stated that the oxidative stress reduction that resulted from the antioxidant absorption lasted for up to 20 hours. The study was published in the
American Chemical Society's Journal of Agricultural and Food Chemistry in April, 2010.
It is easy to see that we have made great progress in the area of glaucoma detection and treatment. The road has not been an easy one and many bumps and barriers lie ahead of us. Many researchers have seen their efforts battered and bruised as the struggle ensues. It was Will Rogers who said, "Good judgment comes from experience, and a lot of that comes from bad judgment." But in the end, the struggle of a few researchers will likely benefit us all.
|
