In a new study, researchers have developed a potential new treatment for the eye disease glaucoma that could replace daily eye drops and surgery with a twice-a-year injection to control the buildup of pressure in the eye.
The treatment, which could become the first non-drug, non-surgical, long-acting therapy for glaucoma, uses the injection of a natural and biodegradable material to create a viscous hydrogel—a water-absorbing crosslinked polymer structure—that opens an alternate pathway for excess fluid to leave the eye.
The researchers envision the injection being done as an office procedure that could be part of regular patient visits.
The research was conducted by a team at Georgia Tech and Emory University.
As many as 75 million people worldwide have glaucoma, which is the leading cause of irreversible blindness. Glaucoma damage is caused by excess pressure in the eye that injures the optic nerve.
Current treatments attempt to reduce this intraocular pressure through the daily application of eye drops, or through surgery or implantation of medical devices, but these treatments are often unsuccessful.
In the study, the team uses a tiny hollow needle to inject a polymer preparation into a structure just below the surface of the eye called the suprachoroidal space (SCS).
There are normally two pathways for the aqueous fluid to leave the eye. The dominant path is through a structure known as the trabecular meshwork, which is located at the front of the eye.
The lesser pathway is through the SCS, which normally has only a very small gap.
In glaucoma, the dominant pathway is blocked, so to lessen pressure, treatments are created to open the lesser pathway enough to let the aqueous humor flow out.
In this research, the hydrogel props open the SCS path. A hollow microneedle less than a millimeter long is used to inject a droplet (about 50 microliters) of the hydrogel-precursor material.
That gel structure can keep the SCS pathway open for a period of months.
The injection would take just a few minutes and would involve a doctor making a small injection just below the surface of the eye in combination with numbing and cleaning the injection site.
The researchers did not observe significant inflammation resulting from the procedure.
The pressure reduction was sustained for four months. The researchers are now working to extend that time by modifying the polymer material—hyaluronic acid—with the goal of providing treatment benefits for at least six months.
That would coincide with the office visit schedule of many patients.
Beyond extending the time between treatments, the researchers will need to demonstrate that the injection can be repeated without harming the eye.
One author of the study is Professor Ross Ethier.
The study is published in Advanced Science.
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