Portable retina camera not requiring dilating prototyped

Photo: University of Illinois

It’s the part of the eye exam everyone hates: the pupil-dilating eye drops. The drops work by opening the pupil and preventing the iris from constricting in response to light and are often used for routine examination and photography of the back of the eye. The drops sting, can take up to 30 minutes to work, and cause blurry vision for several hours afterwards, often making them inconvenient for both patient and doctor.

Now, researchers at the University of Illinois at Chicago College of Medicine and Massachusetts Eye and Ear/Harvard Medical School have developed a cheap, portable camera that can photograph the retina without the need for pupil-dilating eye drops. Made out of simple parts mostly available online, the camera’s total cost is about $185.

“As residents seeing patients in the hospital, there are often times when we are not allowed to dilate patients — neurosurgery patients for example,” said Dr. Bailey Shen, a second-year ophthalmology resident at the UIC College of Medicine. “Also, there are times when we find something abnormal in the back of the eye, but it is not practical to wheel the patient all the way over to the outpatient eye clinic just for a photograph.”

The prototype camera can be carried in your pocket, Shen said, and can take pictures of the back of the eye without eye drops. The pictures can be shared with other doctors, or attached to the patient’s medical record.

The camera is based on the Raspberry Pi 2 computer, a low-cost, single-board computer designed to teach children how to build and program computers. The board hooks up to a small, cheap infrared camera, and a dual infrared- and white-light-emitting diode. A handful of other components – a lens, a small display screen and several cables – make up the rest of the camera.

The camera works by first emitting infrared light, which the iris – the muscle that controls the opening of the pupil – does not react to. Most retina cameras use white light, which is why pupil-dilating eye drops are needed.

The infrared light is used to focus the camera on the retina, which can take a few seconds. Once focused, a quick flash of white light is delivered as the picture is taken. Cameras exist that use this same infrared/white light technique, but they are bulky and often cost thousands of dollars.

Shen’s camera photos show the retina and its blood supply as well as the portion of the optic nerve that leads into the retina. It can reveal health issues that include diabetes, glaucoma and elevated pressure around the brain.

Shen and his co-author, Dr. Shizuo Mukai, associate professor of ophthalmology at Harvard Medical School and a retina surgeon at Massachusetts Eye and Ear, describe their camera and provide a shopping list of parts, instructions for assembly, and the code needed to program the camera in the Journal of Ophthalmology.

“This is an open-source device that is cheap and easy to build,” said Mukai. “We expect that others who build our camera will add their own improvements and innovations.”

“The device is currently just a prototype, but it shows that it is possible to build a cheap camera capable of taking quality pictures of the retina without dilating eye drops, “ Shen said. “It would be cool someday if this device or something similar was carried around in the white-coat pockets of every ophthalmology resident and used by physicians outside of ophthalmology as well.”

Source: University of Illinois

Zinc in Retina May Protect and Regenerate Optic Nerve in Glaucoma Patients

Connecting pieces of information by finding a common thread often takes glaucoma researchers in unexpected directions. Zinc is one such thread that joined together different experts at Boston Children’s Hospital and Harvard Medical School. Their collaboration uncovered surprising information about zinc in the retina, which led to the discovery that removing excess zinc helps protect the optic nerve and encourages regeneration. Only more research will tell whether this will lead to future glaucoma treatments, but one thing is certain—these scientists plan to keep moving forward together.

Zinc is the second most abundant trace metal in the human body (next to calcium) and an essential dietary nutrient that’s crucial for normal cell growth, a strong immune system and healthy nerve function—to name just a few of its widespread influences. It’s also indispensable for vision and keeping eyes healthy. Vitamin A may be known as the main nutrient responsible for vision, but it needs zinc to help it convert into the substance that enables low-light vision.

There’s a significant amount of zinc in the retina, where it’s responsible for many jobs beyond transforming vitamin A. For example, if you could see what’s happening at the cellular level, you’d see zinc regulating communication between retinal cells and controlling channels that allow ions to flow in and out of cells. The retinal pigment epithelium, a barrier that transports nutrients into the retina, can only function when zinc-dependent proteins are present. All of the different types of nerve cells in the eye contain zinc, where it triggers biochemical reactions and helps control neurotransmitters that travel between retinal nerve cells.

But there’s something else to know about zinc: too much can be toxic. The body maintains a precise balance by increasing or decreasing the amount absorbed in the gut and by active mechanisms that take place inside cells after zinc is digested. The retina also has several ways to protect itself, like transporters that can carry away unwanted zinc. When these protective mechanisms aren’t working properly or they’re overwhelmed, health problems can arise.

Ophthalmologists at Boston Children’s Hospital and Harvard Medical School have spent years exploring ways to protect and regenerate nerve cells in the eye. Meanwhile, experts in the Department of Neurology were busy studying the role of zinc in cell death. In 2010, they decided to collaborate to learn about zinc’s impact on retinal ganglion cells, which receive visual signals and form the optic nerve that delivers information to the brain.

They discovered that zinc is released from cells within an hour after the optic nerve is injured acutely—but they were surprised to find that it didn’t come from retinal ganglion cells. Instead, zinc was released from amacrine cells, which are interneurons in the retina that communicate with ganglion cells. Retinal ganglion cells only began to die after they’re affected by high levels of zinc leaking from injured amacrine cells.

That news alone was an exciting breakthrough, but there’s more: In lab mice, damaged retinal ganglion cells survived longer and were able to regenerate when excess zinc was removed through a chemical process called chelation. To top that off, they learned there’s a delay before zinc impacts ganglion cells, which means that chelation could lead to significant cell survival and regeneration even if treatment was delayed for several days.

It took the team from Boston about six years to achieve these results and they’re not stopping now. They plan to explore how zinc causes cell death and blocks regeneration. If they can get the funding, they’d like to develop a slow-release formula that would chelate zinc for an extended time. Then they’d have to conduct clinical trials to prove zinc chelation in the retina is safe and effective in people with other conditions, such as glaucoma. In the meantime, the glaucoma community has a new road to follow, one that could lead to treatment possibilities previously unimagined.

Source: Glaucoma Research Foundation

Research: Saving Sight in Glaucoma

Glucoma

Glaucoma involves sensitivity to ocular pressure (not just elevated pressure) that is translated or transduced to stress that degrades the optic nerve over time. Current glaucoma therapies lower pressure using eye drops, surgery, or both in order to reduce stress transduced to the optic nerve. This approach is effective for many patients. But for those who continue to lose vision, where should we turn for new clinical therapies? Continue reading “Research: Saving Sight in Glaucoma”

Philips Volcano announces more than 5,000 Coronary Artery Disease patients enrolled in iFR Outcomes Trials

Philips announced that a combined total of more than 5,000 patients have been enrolled in three prospective clinical studies to assess the safety of deferring cardiovascular interventions using Philips Volcano’s proprietary iFR (instant wave-Free Ratio) pressure measurement technology versus conventional FFR (Fractional Flow Reserve) measurements.

During catheterization procedures to assess and treat a patient’s coronary arteries, a guide wire is used to obtain measurements of the blood pressure at specific points inside the affected arteries to help assess the severity of the blockage(s). There is a growing body of clinical evidence that the use of FFR in conjunction with interventional X-ray helps improve procedure outcomes, and reduces healthcare costs.
Full coverage can be found from Philips website by clicking here.

China CFDA clears 166 innovative devices including artifical cornea

China CFDA approved 166 innovative medical devices applications in 2014, including acellular corneal stroma, the first artifical cornea product developed by Chinese firm.

In 2015, CFDA also approved devices aiming at new clinical applications, such as a particle therapy equipment for treating tumor.

CFDA also announced approval to MERS and Ebola test kits.