Vision Loss and Eye Disease | Stem Cells Australia
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Vision Loss and Eye Disease
The eye is a complex organ that is made up of many specialised parts. Each one of these specialised parts are themselves made of many different types of cells that all play a specific role in the healthy functioning of the eye. The eye contains several types of stem cells that constantly replace specialised cells that become worn out or damaged.
One type of stem cell called the ‘limbal’ stem cells sit at the edge of the eye’s cornea. These stem cells help by making new cells for the cornea – the transparent front of the eye. Limbal stem cells are very important, as they help repair any damage to the cornea. If these cells are lost due to injury or disease, the cornea can’t repair itself, which results in a loss of vision.
Disorders or diseases of the eye occur when one or more of these specialised parts is damaged, and/or stops working properly. Different disorders develop depending upon which part(s) are not working. For example, some people have blurred or no central vision due to damage to part of the retina at the back of the eye (referred to as macular degeneration). Other people may experience vision loss due to a genetic disorder that affects certain cells in the retina (such as Retinitis Pigmentosa) or degeneration of the optic nerve so that it can no longer relay information from the eye to the brain (referred to as Optic Atrophy).
How could stem cells help?
There are many diseases that cause vision loss, and many of them are not yet treatable. Researchers are working to understand what causes these diseases, what other types of stem cells reside in the eye and how stem cells might be used to repair or even restore vision to patients. Below are some ways that researchers are using stem cells:
Understanding the disease
Researchers are using stem cells to study many different aspects of the eye, from how the eye is made to what causes eye diseases and how to treat them.
Developing new gene therapies: Researchers can now create many of the cells from the eye in the laboratory using the patient’s own cells. Scientists can use these models of the eye to test possible new gene therapies before starting clinical trials.
Replacing lost cells
Scientists have been researching the use of limbal cells in patients with damaged corneas (the clear outermost part of the eye). Holoclar® is clinically approved in Europe as a stem cell treatment for corneal blindness and is currently being evaluated in an Australian trial. This treatment restores vision to patients with damaged corneas by transplanting lab-grown limbal stem cells into areas of the eye lacking these cells.
This treatment can only be used in patients who still have healthy limbal stem cells left to be grown in the lab. Replacing lost or damaged cells is also being studied for damage to other parts of the eye, such as in cells located in and around the retina. Working out how to administer the right type of cells in the right number so that they can restore function represents a substantial challenge and is likely to require a tailored approach for each form of blindness.
What are the challenges?
Many diseases that cause blindness are still not treatable. Researchers are working to understand what causes these diseases, what other types of stem cells reside in the eye and how stem cells might be used to repair or even restore vision to patients. Many of these studies are still in the early stages of investigation. Just as Holoclar® took more than twenty years to develop into a safe and successful treatment, today’s research and discoveries will take time to develop into safe and reliable treatments for other types of blindness.
Where can I find out more about clinical trials?
There are a number of sites that list clinical trials. You can search the clinicaltrials.gov registry by entering the condition of interest and ‘stem cells’ under ‘other terms’. Please note that the scientific justification for the intervention and the credentials of those offering the service may have NOT been fully evaluated by this registry. Your findings may include listings that are NOT legitimate clinical trials. Please consult with your medical specialist or general practitioner as they are best placed to advise you on whether you would be a good candidate for a trial given your circumstances.
Please note: Although some clinics may claim to already offer stem cell treatments for various forms of vision loss, there are serious questions about the scientific rationale and the safety of many of these approaches. Currently, other than corneal grafting, there are no proven, safe and effective stem cell treatments for vision loss available in Australia, the EU, US or elsewhere.
Some of this material has been adapted from factsheets produced by EuroStemCell.org under a Creative Commons license.
Where else can I go to find out more?
Macular Degeneration & Stem Cell Fact Sheet
international Society for Stem Cell Research