By Marc Steingesser
I am an individual affected by ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome. I learned in my 40s (while attending a National Foundation for Ectodermal Dysplasias Family Conference) there was a significant chance my vision would be impacted by EEC-related limbal stem cell deficiency (LSCD).
The progression of LSCD can occur rapidly or gradually (months to years) and results in vascularization, erosion, clouding, and scarring of the cornea (the transparent outer layer of the eye that covers the pupil and iris). The end result of LSCD is corneal opacity and blindness.
Learn More about Limbal Stem Cell DeficiencySteps I Took to Slow LSCD Progression
Having learned of my risk for developing EEC-related LSCD, I consulted a corneal specialist and discovered it had already started in one of my eyes. Therefore, I began taking measures to slow the progression of LSCD by protecting my corneas and becoming educated on treatment options that included:
- Wearing scleral (PROSE) lenses to address EEC-related dry eye symptoms (primarily, chronic irritation/inflammation and increased corneal regenerative demand) that occur due to EEC-related meibomian gland dysfunction (MGD). Meibomian glands are located in the eye lid. They are responsible for producing the oil required to create a viable tear film that covers the cornea and protects it from drying out while your eye lids are open. They also protect from abrasion by the underside of the eye lids when they are closed. Those with EEC often have low or non-functioning meibomian glands/MGD. Without oil, the watery/aqueous component of the tear film (produced by the lacrimal gland) immediately breaks apart when the eye lids are open. This exposes the cornea to the air which results in the dry eye symptoms mentioned above.
- Staying up-to-date on corneal regeneration research (potential future LSCD treatments appear promising!).
- Searching out and consulting with corneal specialists in the United States and abroad on current LSCD treatment options.
- Discovering a doctor that developed a variety of limbal stem cell transplant treatments he’s performed on patients from around the world since 1989.
The Role of Limbal Stem Cells in Corneal Health
In case you’re not up to speed on limbal stem cells (LSCs), please allow me to explain. LSCs are located around the perimeter of the cornea and provide two crucial functions for maintaining a functional/transparent cornea:
- First, they provide a constant supply of corneal epithelial cells that are needed to regenerate the clear surface layer of the cornea (which is a form of specialized skin that constantly replaces older/worn out cells with newer ones – just like the rest of your skin).
- Second, limbal stem cells reside in the limbus, a structure that acts as a barrier between the cornea and sclera (the white part of the eye) and prevents invasion of blood vessels and opaque conjunctival cells into the cornea. LSCD is basically the depletion, and ultimately complete loss, of functional limbal stem cells that results in the inability to properly regenerate the surface layer of the cornea (the cause of erosions and scarring) and the inability to prevent invasion of opaque conjunctival cells and blood vessels into the cornea that over time results in corneal opacity and blindness.
Why Conventional Treatments Don’t Work for EEC-Related LSCD
Why those with EEC develop LSCD has yet to be characterized. Until it is, development of a treatment to prevent/reverse EEC-related LSCD was generally thought impossible. A leading-edge treatment for unilateral (just one affected eye) LSCD is known as a limbal stem cell autograft – where viable limbal stem cells are harvested from a patient’s healthy eye and transplanted into their (typically trauma-caused) LSCD-affected eye.
Those with EEC-related LSCD are not candidates for this treatment since their LSCD is genetically based (i.e. both eyes are affected by LSCD; although, manifestation of LSCD may take longer in one eye than the other). Likewise, conventional corneal transplants are not sustainable for those with EEC-related LSCD because functional limbal stem cells are required to regenerate the surface of the transplanted cornea and maintain the barrier between the transplanted cornea and sclera.
A Breakthrough: Limbal Stem Cell Allografts
To my surprise (due to other doctors not knowing or mentioning it), I learned that Dr. Edward Holland at the Cincinnati Eye Institute developed a treatment, known as a limbal stem cell allograft, which transplants limbal stem cell tissue from a donor (living or deceased) into the eye of a LSCD patient. This type of transplant is treated similarly to an organ (ex. kidney, lung, liver, and heart) transplant in that immune suppression drugs are used post-transplant to prevent the patient from rejecting the donated tissue.
Conventional corneal transplants (for those without LSCD) do not require immune suppression because the cornea is normally an immune privileged tissue (i.e. there are normally no blood vessels within the cornea, so a donated transplanted cornea has reduced exposure to the patient’s immune system). But, as previously described, the cornea is no longer immune privileged for individuals with LSCD due to the invasion of blood vessels that increases the cornea’s exposure to the immune system.
Interestingly, and of great consequence, people who have functional limbal stem cells restored via a limbal stem cell allograft are viable candidates for conventional corneal transplants. This may be needed for those that have experienced LSCD-related extensive/multi-layer damage to their cornea prior to a limbal stem cell allograft.
My Experience Undergoing Limbal Stem Cell Transplants
Limbal stem cell allografts are the first currently available and viable treatment for treating EEC-related LSCD that I discovered after over a decade of active searching. In August of 2022, I became the second EEC-affected patient to undergo the procedure with Dr. Holland (and again for my other eye in May of 2023).
Both eyes still look great! No signs of rejection, corneal epithelial cells (generated by the transplanted limbal stem cells) now cover the surface of my corneas, and my quality of vision is very good. Dr. Holland has since performed limbal stem cell allografts on additional EEC patients with varied outcomes so far. Each case has been unique with different challenges.
Risks, Considerations, and Future Treatment Possibilities
Of course, limbal stem cell allografts include risks of complications, failure, and irreversible loss of vision. These are possibilities to discuss thoroughly with your doctor. In addition, use of immune suppression drugs carries risks as well. Limbal stem cell allografts may not be an option for all EEC-related LSCD patients. Each case must be evaluated for suitability.
Undergoing a limbal stem cell allograft should not prevent a patient from benefiting from future treatments (if/when available) that will use a patient’s own cells to grow new limbal stem cells and corneas (that would eliminate the need for immune suppression). Until then, if failure/rejection of a limbal stem cell allograft does occur, then a limbal stem cell allograft can be redone with new donor tissue. Lastly, in my case, conventional medical insurance fully covered the procedure and related travel expenses.
I hope this information is helpful – warm regards to you all.
Marc Steingesser is a guest blogger for the National Foundation for Ectodermal Dysplasias. He is affected by EEC syndrome.
Understanding and Treating Limbal Stem Cell Deficiency
By Edward Holland, M.D., Cincinnati Eye Institute
Limbal stem cell deficiency is an often under diagnosed condition for which visual symptoms can range from mild to devastating. The first step to appropriate treatment is establishing care with an ophthalmologist, ideally a cornea specialist. While not all cornea specialists offer the full spectrum of surgical care for limbal stem cell deficiency, they are all trained to diagnose and identify indications for its treatment.
Should treatment beyond the offerings of your local cornea specialist become necessary, you can ask for a referral to be sent to one of several limbal stem cell deficiency centers of excellence. As of right now, we have two other locations which include University of California Irvine with Dr. Marjan Farid and Dr. Thomas Dohlman at Harvard.
Surgical care of limbal stem cell deficiency is often complex and individualized to a patient’s needs. In general, co-existing glaucoma and eyelid problems are corrected first. Once these are addressed and if a patient is an appropriate candidate for immunosuppression medication and surgery, limbal stem cell transplantation can then be performed. Patients may or may not require a corneal transplant thereafter depending on the level of corneal scarring.