Determining correct dosing of anti-rejection medications in DMEK patients
The standard regimen of post-operative medications for cornea transplant recipients include antibiotics and relatively strong steroid eye drops taken to prevent your immune system from rejecting the new donor tissue. Having helped pioneer the DMEK technique and observing that DMEK had such a low risk of rejection, Dr. Price and the Cornea Research Foundation embarked on a series of studies to evaluate corticosteroid eye drop strength and dosing regimens over the last several years.
The goal of the studies were to protect the transplant from immunologic graft rejection while reducing the corticosteroid side effects. This is important because we know through tracking our transplant outcomes that 1 in 3 patients will experience the unfortunate side effect of pressure increases within one year using a standard steroid eye drop regimen. If left untreated, the pressure problems can eventually lead to glaucoma and cause permanent vision loss.
Within the studies, we compared 3 different steroid medications of varying strength. Groups of patients were randomized to receive different steroid eye drops and were followed for one year. We evaluated the health of their transplant as well as any pressure changes within that year. Once patients reached the one year mark, they were given the option to either stay on the drop, switch to a lower dose if they were on the highest dose, or go off the drops entirely. Whichever they chose, we continued to examine the transplant and the eye pressure regularly.
We found that the risk of rejection was very low even when patients switched to a low-strength steroid eye drop at 1 month. So now we reduce steroid strength at 1 to 2 months after DMEK and that substantially reduces the risk of pressure elevation.
A few of those who discontinued steroid eye drops at one year (about 1 out of 17) experienced a rejection episode. In most cases it was mild and could be successfully treated by resuming steroids. Usually, the patient didn’t even realize they were having a rejection episode - our doctors detected it during one of the planned study examinations. Those who chose to continue using a low-strength eye drop did not experience any incidence of graft rejection episodes or pressure increases. Therefore our current recommendation is to stay on the low dose steroid long term.
We continue to monitor the progress of these individuals over the long run. We believe the findings from our anti-rejection medication studies will allow us to reduce the incidence of future glaucoma development in cornea transplant patients, particularly since many new DMEK surgeons are adopting our recommended dosing through the sharing of our results in leading ophthalmology publications.
Finding the Causes of Keratoconus and Fuchs’ Dystrophy
We are collecting corneal tissue from transplant patients for studies to help identify the underlying causes of keratoconus and Fuchs’ dystrophy. The results of these studies will hopefully result in earlier identification of these conditions and better treatment options.
Corneal strengthening treatments for Keratoconus
In adolescents and young adults the cornea sometimes weakens and bulges outward causing visual distortion. This condition is called keratoconus, which literally means “cone-shaped cornea”. We have conducted a series of studies over the last 8 years using riboflavin (vitamin B2) eye drops and a UV light in a treatment designed to strengthen and stabilize the cornea, to prevent the need for a cornea transplant. A global consensus document now recommends this as a first line treatment for keratoconus and it recently received approval from the Food and Drug Administration (FDA) for routine use in the USA. We have studies underway with conventional and accelerated treatments.
Further Refining DMEK
We are always looking for new ways to further improve the transplant procedure known as DMEK. We are evaluating new ways of inserting the donor tissue into the eye to help minimize any trauma to the tissue. Also, many of our patients have cataract surgery at the same time as DMEK, so we are evaluating new methods of imaging the eye before surgery to help optimize vision without glasses afterwards.
New Treatment for Eyelid Lesions
Some children suffer from painful lesions on the undersides of their eyelids because they were born without the ability to make a key enzyme known as plasminogen. We are evaluating eye drops that contain human plasminogen to help alleviate the symptoms, encourage healing and prevent recurrence of the painful lesions.
Some people are missing all or part of the iris, the colored portion of the eye. This can be caused by a birth defect, or the tissue-thin iris can be damaged later in life by an accident or injury. Because the iris regulates the amount of light entering the eye, a lack of one can be extremely painful on bright days. Dr. Price equates the lack of an iris to the feeling of stepping outside into the sun on a bright sunny day. Only, without an iris, your eyes never adjust to the brightness. The purpose of this study is to evaluate an artificial iris, which can improve quality of life and cosmetic appearance. The artificial iris is flexible so that it can fit through a small incision and it is hand-painted to have a very natural appearance.
Treatment for Congenital Aniridia
Congenital aniridia is a condition in which mutations in a key gene impair proper development of various parts of the eye, including the iris, which give your eye its color. We are evaluating an investigational medication to see if it may help override a specific type of congenital aniridia and help prevent associated eye problems.
Treatment for Presbyopia
As we age, the lens inside our eye has more difficulty fully adjusting to help us see up close. So, many of us find that we need to start using glasses for near work or reading after we reach the age of 40 or 50 years old. This condition is called presbyopia, which literally means “old eyes”. We are participating in a study to evaluate whether an investigational eye drop treatment can help preserve our ability to see up close and avoid the need for reading glasses.
New Treatments for Dry Eyes
Dry eye disease is a surprisingly common condition, affecting about 1 in 10 people. It tends to be more prevalent in women than men, increases in frequency with age, and can be a problem after different types of eye surgery. Many are unaware until they have the condition that there are different levels of dryness, varying from mildly irritating to severely debilitating. It can get progressively worse if left untreated. We are evaluating several exciting new treatments to help alleviate feelings of dry, irritated eyes.