Wouldn’t it be nice if there was a way to grow retinal cells in a lab and use those cells as treatments for eye disease? What about advanced optics? Can they be used to help those with limited vision do things like drive a car? Well thanks to ongoing research, these things are either close to becoming a viable treatment or are currently available in some places.
Biologics
Work done in the lab of David Gamm, director of the University of Wisconsin-Madison McPherson Eye Research Institute and the Morgridge Institute for Research has shown that stem cell replacement therapy using lab-grown photoreceptors shows promise in treating retinal disease. The rub is that stem cell treatments need to be tested in animals before they can be used in humans. Since human cells won’t function properly when transplanted into other animal species, another test subject had to be found. Since pig and human retinas share many features, pigs are good subjects for testing ocular therapies. This allows researchers to get a better sense of what the cells can do.
Once scientists obtained pig stem cells, the next step was to turn them into retinal cells. A scientist at Morgridge, Ron Edwards, used the Gamm’s established protocols to see if it would work on the pig stem cells. The protocol was based on human gestation of 40 weeks. A pig’s gestation is only 20 weeks, so Edwards decided to use the same protocol but cut the timing in half. It worked, and scientists at Morgridge were able to make a large number of retinal organoids from that protocol.
Researchers used immunocytochemistry techniques to characterize the proteins associated with specific retinal cells present at early-stage and late-stage development in pig and human models. Each cell was tagged with a barcode and sequenced individually. The data that were gathered were then used to group similar cells together. This gave the scientists detailed insights into the nature of the cell types, including rod and cone photoreceptors.
“It’s an unbiased and very comprehensive view of what genes are expressed in each cell type in the organoid,” says Beth Moore, a computational biologist at Morgridge, who worked on this project. “It’s a different type of marker from the immunochemistry. It’s a different way to come to the same conclusion of identifying different cell types.”
Scientists have begun to do transplants in pigs using the photoreceptors from the pig organoids to determine if they can establish connections and form synapses with downstream neurons.
Bioptics
What if vision is impaired but can be improved through the use of bioptics. The University of Alabama Low Vision Clinic is working with the Alabama Department of Rehabilitation to train the visually impaired to drive using bioptics, which are standard eyeglasses with a small telescopic lens system to enhance distance vision.
This is legal in 37 states and requires extensive training. Drivers have to pass multiple evaluation by optometrists, ophthalmologists, occupational therapists and certified driving rehabilitation specialists. A failure at any stage can bring things to a standstill. Drivers who use bioptics are required to have annual eye exams, especially if their vision gets worse over time.
The first step is to have an eye exam to determine whether the person meets legal and safety criteria, such as specific visual acuity requirements, peripheral vision standards, reaction time, and situational awareness. Once the person received the specialized eyeglasses, he or she needs to be trained on how to use them. One aspect of training involves bioptic spotting training. This helps persons with low vision learn how to use the bioptic telescope to identify details while driving, such as road signs or hazards, while relying on the regular lens for overall awareness. The training stresses the coordination of head and eye movements to safely obtain information without losing awareness of the broader driving environment. It acts as a bridge between clinical setting and real-world driving.
After a person is cleared for the next phase, then there is behind the wheel training with a certified driver rehab specialist, and logging additional practice time with an instructor. Once the person demonstrated consistent safety and competency, the person can obtain a bioptic driver’s license and can drive independently.
The bioptics program at the University of Alabama Low Vision Clinic helps people with low vision drive a car, which allows them to maintain their independence. Work at the University of Wisconsin-Madison McPherson Eye Research Institute and the Morgridge Institute for Research demonstrated how pig organoids can be used to develop treatments for retinal disease. The work of scientists, eye doctors and occupational therapists shows that treatments for retinal diseases may one day be developed from stem cells and those with low vision can do things like drive through technology, such as bioptics.