Pioneering device can take 3D images to detect eye diseases

 

A pioneering low-cost device which takes 3D images could transform eye screening and treatment across the globe.   The device, developed by researchers from the University of Strathclyde, captures 3-D images of the retina, the back of the eye and cornea, and can be added at low cost to a slit lamp, a device commonly used by optometrists.   Patients with conditions such as glaucoma, the third most common cause of visual impairment worldwide, with an estimated 7.7 million people affected, are often diagnosed by highly-trained specialists, who look at photos and give a subjective opinion on the 3D structure of the back of the eye. Although there are existing instruments for 3D imaging, including Optical Coherence Tomography technology – the machines can cost up to £100,000, often making them too expensive for large-scale population use, especially in low-income countries. However, optometrists all over the world have access to slit lamps. The new technology is a simple and inexpensive add-on to a standard lamp, and can extend 3D eye imaging to all settings where optometrists are present. It is so simple that a modified version of the technology brings potential of 3D retinal ‘selfies’ without an operator, meaning it could also be deployed in unassisted settings, like pharmacies. The technology can also be used to image the front of the eye, which is important for cornea transplant patients as many machines can’t measure the edge of the cornea. The device has been developed by Dr Mario Giardini, Dr Ian Coghill, and Kirsty Jordan, at the Department of Biomedical Engineering of the University of Strathclyde.   Dr Giardini said: “Patients can be imaged easily and inexpensively, without the need for a specialist to be present. Our device reliably takes 3D images, and it is comfortable and fast, at less than a second. “The technology has the potential to revolutionise the screening and follow-up within the community of conditions such as glaucoma, as any optometrist, anywhere in the world, could afford it. This work makes eye diagnostics more accessible, reducing inequalities.” Dr Iain Livingstone, Consultant Ophthalmologist at NHS Forth Valley, who has collaborated with Dr Giardini on previous ophthalmology projects, said: “So much of what we do as eye doctors depends on seeing things in 3D. While photographs can be helpful, this innovation uses visible light to re-create a high fidelity 3D representation of eye structures, allowing precise measurements to be taken in a completely new way, piggybacking on the method of examination we already do routinely. “It’s a crucial addition to the way we interpret information, harnessing digital to glean so much more from a slit lamp exam, with potential reach far beyond the hospital toward Community Optometry, bringing nuanced measuring tools closer to home for patients.” The researchers also hope it can eventually be used to detect eye cancer and Dr Livingstone added:  “This addition turns a slit lamp into a ‘3D eye scanner’ with potential to supplant ocular ultrasound for measuring solid tumours of the eye.” The initial prototyping was funded by the Engineering and Physics Research Council, part of UK Research & Innovation. The next step is now to make the technology available to the medical community, and the University has partnered with IDCP, a digital innovation group, to turn it into a medical product. CEO of IDCP group, Jan Boers, said: “Working with the University of Strathclyde to develop new technology for eye screening has been very productive, and this development will be a significant step for enabling more accurate, accessible, and cost-effective solutions to eye diagnostics globally. This is a great addition to our activities in the field of eye screening with RetinaScope and IDCP Scotland.” Jamie Thomson, Managing Director of IDCP Scotland, who received support from Scotland’s national economic development agency Scottish Enterprise, with a SMART grant of £85,000, said: “As a University of Strathclyde alumnus, it gives me great pride to be working closely with the team helping to develop this technology, which has the potential to improve the quality of patient care and fits within IDCP Scotland’s key objective to revolutionise patient care within ophthalmology.”

 

‘Positive Stress’ Helps Protect Eye from Glaucoma

Working in mice, scientists at Washington University School of Medicine in St. Louis have devised a treatment that prevents the optic nerve injury that occurs in glaucoma, a neurodegenerative disease that is a leading cause of blindness.

Researchers increased the resistance of optic nerve cells to damage by repeatedly exposing the mice to low levels of oxygen similar to those found at high altitudes. The stress of the intermittent low-oxygen environment induces a protective response called tolerance that makes nerve cells -- including those in the eye -- less vulnerable to harm.
The study, published online in Molecular Medicine, is the first to show that tolerance induced by preconditioning can protect against a neurodegenerative disease.
Stress is typically thought of as a negative phenomenon, but senior author Jeffrey M. Gidday, PhD, associate professor of neurological surgery and ophthalmology, and others have previously shown that the right kinds of stress, such as exercise and low-oxygen environments, can precondition cells and induce changes that make them more resistant to injury and disease.
Scientists previously thought tolerance in the central nervous system only lasted for a few days. But last year Gidday developed a preconditioning protocol​ that extended the effects of tolerance from days to months. By exposing mice to hypoxia, or low oxygen concentrations, several times over a two-week period, Gidday and colleagues triggered an extended period of tolerance. After preconditioning ended, the brain was protected from stroke damage for at least 8 weeks.
"Once we discovered tolerance could be extended, we wondered whether this protracted period of injury resistance could also protect against the slow, progressive loss of neurons that characterizes neurodegenerative diseases," Gidday says.
To find out, Gidday turned to an animal model of glaucoma, a condition linked to increases in the pressure of the fluid that fills the eye. The only treatments for glaucoma are drugs that reduce this pressure; there are no therapies designed to protect the retina and optic nerves from harm.
Scientists classify glaucoma as a neurodegenerative disease based on how slowly and progressively it kills retinal ganglion cells. The bodies of these cells are located in the retina of the eye; their branches or axons come together in bundles and form the optic nerves. Scientists don't know if damage begins in the bodies or axons of the cells, but as more and more retinal ganglion cells die, patients experience peripheral vision loss and eventually become blind.
For the new study, Yanli Zhu, MD, research instructor in neurosurgery, induced glaucoma in mice by tying off vessels that normally allow fluid to drain from the eye. This causes pressure in the eye to increase. Zhu then assessed how many cell bodies and axons of retinal ganglion cells were intact after three or 10 weeks.
The investigators found that normal mice lost an average of 30 percent of their retinal ganglion cell bodies after 10 weeks of glaucoma. But mice that received the preconditioning before glaucoma-inducing surgery lost only 3 percent of retinal ganglion cell bodies.
"We also showed that preconditioned mice lost significantly fewer retinal ganglion cell axons," Zhu says.
Gidday is currently investigating which genes are activated or repressed by preconditioning. He hopes to identify the changes in gene activity that make cells resistant to damage.
"Previous research has shown that there are literally hundreds of survival genes built into our DNA that are normally inactive," Gidday says. "When these genes are activated, the proteins they encode can make cells much less vulnerable to a variety of injuries."
Identifying specific survival genes should help scientists develop drugs that can activate them, according to Gidday.
Neurologists are currently conducting clinical trials to see if stress-induced tolerance can reduce brain damage after acute injuries like stroke, subarachnoid hemorrhage or trauma.
Gidday hopes his new finding will promote studies of tolerance's potential usefulness in animal models of Parkinson's disease, Alzheimer's disease and other neurodegenerative conditions.
"Neurons in the central nervous system appear to be hard-wired for survival," Gidday says. "This is one of the first steps in establishing a framework for how we can take advantage of that metaphorical wiring and use positive stress to help treat a variety of neurological diseases."

Scientists have found a way in mice to prevent damage to the optic nerves that normally occurs in glaucoma. Using high-power micrographs like this one of the optic nerve in cross-section, they can quantify glaucoma damage to the axons of the retinal ganglion axons passing through the nerve. In this image, those axons are green, and the branches and nuclei of the astrocytes surrounding them are red and blue, respectively. (Credit: Jeff Gidday, PhD)

**Published in "SCIENCE DAILY"