In a new study, researchers developed a new surgical approach to treat progressive blindness in older people.
The research was conducted by a team at the University of Southern California.
Dry age-related macular degeneration (dry AMD) poses a significant clinical challenge.
It is one of the leading causes of progressive blindness, robbing millions of people over the age of 65 of their central vision, and it often hinders patients’ abilities to read books, drive and discern the faces of their loved ones.
Although vitamin-based supplements may slow progression, no treatments currently exist.
The USC team saw in this situation an opportunity to innovate and pioneer a novel treatment approach for dry AMD patients.
Theirs has been a feat of scientific and surgical prowess, and over a decade of their diligence and ingenuity has resulted in what may become the first FDA-approved treatment to transform the prospects of regaining vision for millions of patients.
In the study, the team developed a stem cell-based retinal implant and accompanying surgical procedure to help restore vision to dry AMD patients.
The team accomplished a remarkable multi-part feat that required inventiveness at every turn, starting with designing the novel retinal implant.
Dry AMD causes a single layer of cells in the retina called the retinal pigment epithelium (RPE) to deteriorate.
The team decided to utilize stem cells to grow RPE tissue in the lab, with the ultimate goal of implanting those cells in patients’ eyes to slow or reverse the damage.
The scientists created a thin membrane made of parylene on which to grow the cells in a single, even layer. Once they had created this RPE layer, the next challenge was to successfully implant it in the eye.
There are very few tools for performing surgery within the sub-retinal space.
Most available tools were designed 30 to 40 years ago, are relatively bulky and are generally meant to remove scar tissue or other lesions rather than insert anything into the sub-retinal space.
The team decided that the most promising option was to start fresh and design a brand-new tool to fit their purpose.
This new tool had to fit a number of criteria: it needed to be made of completely non-toxic materials so as not to harm patients, its design had to be easily reproducible, and it had to be small enough—on a scale of millimeters—to perform minimally invasive surgery inside the eye but large enough to prevent crushing the tissue implant it was meant to deliver.
The surgeons worked with materials and design engineers to create single-use forceps with an internal compartment to encapsulate the implant and a roller-style thumbwheel to deploy it.
The implant itself is shaped much like a champagne bottle, and the forceps grab onto the narrow end.
Rolling the implant into the device’s compartment causes it to fold into a curved shape, and the surgeon can ultimately release it to lay flat inside the eye.
With the new instrument and implant came an entirely novel surgical approach.
The team created an artificial retinal detachment using a technique called bleb formation, in which a small pocket of space is formed under the retina.
To monitor progress during surgery and prevent complications, the team utilized an advanced imaging technique called optical coherence tomography (OCT) to visualize the dissection at the cellular level.
The team says one of the most rewarding aspects of the entire clinical trial process has been working with patients and witnessing their commitment to making this translation from the research lab to clinical practice possible.
One author of the study is Amir Kashani, M.D., Ph.D.
The study is published in Ophthalmology Retina.
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