As eye care providers, our mission is to provide every professional, optical, medical, and surgical option to our patients in order for them to see their highest potential.
It is always disheartening to me when a patient comes to see me and their best corrected visual acuities are reduced to 20/200 or Finger Counting. Sometimes we have very few options for them under these circumstances. Some of the medical complications that can compromise vision include eye injuries, corneal disease,
keratoconus, eyelid anomalies such as ptosis, cataracts, iritis, glaucoma, retinal diseases, diabetes, and macular degeneration. Some of these problems can be controlled, others treatable but some illnesses are simply beyond therapeutic treatment. In recent medical news, there may be areas of hope for macular degeneration patients using stem cell therapy.
Age-related macular degeneration (AMD) is a medical condition which usually affects older adults and results in a loss of vision in the center of the visual field. Central vision is provided by the macula. The degeneration of the macula is caused by slow sustained death of the cone cells contained within the macula. It is a major cause of blindness and visual impairment in older adults greater than 50 years of age.
According to the January, 2011 L.A. Times article, �Stem cell trial sets sight on blindness,� about 10 million Americans suffer some degree of vision loss caused by AMD and that figure is expected to grow as more baby boomers become senior citizens. Macular degeneration can make it difficult or impossible to read or recognize faces. Central vision is affected, although enough peripheral vision may remain to provide some level of �acceptable vision.� Two forms of macular degeneration exist, wet and dry. The dry, non-exudative form appears as yellow cellular debris called drusen which accumulates between the retinal pigment epithelial layer and the choroid. The wet, exudative form is more serious affecting approximately 10% of patients having macular degeneration. This form of AMD is also referred to as neovascular or exudative macular degeneration and causes vision loss due to the growth of abnormal blood vessels. These blood vessels can leak blood or protein below the macula causing irreversible damage to the photoreceptors.
According to Wikipedia �approximately 10% of patients 66 to 74 years of age will have findings of macular degeneration. The prevalence increases to 30% in patients 75 to 85 years of age. The lifetime risk of developing late-stage macular degeneration is 50% for people that have a relative with macular degeneration, versus 12% for people that do not have relatives with macular degeneration, a fourfold higher risk.� Some of the associated risk factors for AMD include hypertension, high cholesterol, obesity, high fat intake, oxidative stress, Caucasian race, exposure to sunlight especially blue light, smoking, and genetic factors. However, determining a precise cause of macular degeneration has proven illusive.
Until recently, there were no effective medical treatments for wet AMD. New drugs called anti-angiogenics or anti-VEGF agents have been used to cause a regression of the growth of abnormal blood vessels. Vision improvement can be achieved when these drugs are injected directly into the vitreous humor of the eye. But these injections must be repeated on a monthly or bi-monthly basis. The names of these drugs include ranibizumab or Lucentis, pegaptanib or Macugen, and aflibercept or Eylea. Bevacizumab or Avastin is not approved for intraocular use but has been used for other systemic problems and is used as an �off-label� treatment for AMD.
Recently, there has been an increase in the use of certain anti-oxidant vitamin therapies to slow the progression of AMD. Some evidence supports the use of 2 carotenoids, lutein and zeaxanthin, consuming omega-3 fatty acids, and consuming foods with a low glycemic index. Smokers who take high levels of beta-carotene may be at a higher risk for lung cancer and there has been new evidence indicating that vitamin E supplements can increase the risk of heart failure. Anyone who is considering taking any supplement for any reason should always discuss this with their ECP, their family doctor, their internist, their surgeon and their pharmacist.
In the past several weeks, there has been some news concerning the treatment of AMD using stem cell research. Unfortunately, during the last Presidential administration from 2000-2008, stem cell research was halted or slowed down for 8 years. Research companies, medical professionals, and some of the smartest minds in the United States took their research to Europe, Asia, and Canada. On July 19, 2006, President Bush used his veto power for the first time in his presidency to veto the Stem Cell Research Enhancement Act. This bill would have permitted federal money to be used for research where stem cells are derived from the destruction of an embryo.
Two famous actors, Michael J. Fox and Christopher Reeves testified in front of Congressional committees to remove the obstacles that were imposed as well as having the grant money return to medical schools and research companies. But the process was slow at best due to political and religious issues. Michael J. Fox wanted the stem cell research to continue due to his Parkinson�s disease. And Christopher Reeves of �Superman� fame wanted the research to move forward due to his quadriplegia and spinal cord injuries caused by a fall from a horse. Unfortunately he passed away in 2004 from cardiac arrest.
Parents also testified in Congressional hearings in hope of moving stem cell research forward. There was the hope that children with diabetes, strokes, brain injuries, Alzheimer�s, arthritis, Crohn�s disease, diabetes, baldness, cancer, multiple sclerosis, muscle damage, heart damage, and spinal cord injuries could be helped with this research. Perhaps it would ultimately lead to successful treatments and cures for these and other diseases.
The problems that develop from injuries to the central nervous system usually result in little if any improvement. Brain, spinal cord, and retinal problems can be treated, but improvements are usually minimal at best. This is because there are few, if any �repairing� cells that can heal damaged central nervous system tissue. This is in stark contrast to problems that can occur in the peripheral nervous system which has �repairing� or healing cells that can improve nerve injuries to your hands, as an example. That is why Christopher Reeve lobbied Congress so often. He knew that his only hope of walking again or moving his arms would be the miracle cure that may be found in stem cells.
According to WebMD, �two legally blind women with macular degeneration are the first people ever to receive new retina cells grown from human embryonic stem cells.� One patient had dry macular degeneration and the other patient had Stargardt�s disease. According to Dr. Steven Schwartz, the chief of the retina division at the Los Angeles Jules Stein Eye Institute, �stem cell treatment is being developed as a way to prevent blindness in people with early stage macular degeneration. It is not a treatment for blindness.� Before treatment, one patient could only see hands moving in front of her eyes. Within one month she could read five letters on the eye chart, she could see more colors, and was able to see her watch and to use her computer.
This is a phase 1 study that is designed to test the safety, but not the effectiveness of this type of stem cell treatment. The other important aspects concerning this type of testing includes learning about stem cell biology, the possibilities of immune system rejection, and how new cells can develop in the eye. The first published reports show safety and efficacy. This is a positive first step in improving eye health. Hopefully, there may be more possibilities in the future to improve health utilizing these marvelous cells. This research is in its earliest stages so only time and additional research will unravel this potential. Maybe, just maybe, we may see a few stem cell fueled miracles develop in the coming years.