Dr Brian Vohnsen at the Advanced Optical Imaging Group in UCD.
It’s sometimes said the eyes are windows into the soul - but with the right technology they can also offer insights into their own health.
Being able to image tiny structures and cells in the eye can potentially identify the early stages of degenerative blindness, and it may also help eye surgeons carry out corrective procedures. So Dr Brian Vohnsen and his team at the Advanced Optical Imaging Group in UCD are developing ways to image the eye both closely and rapidly.
One of their approaches uses a laser to build up an extremely high-resolution image of the retina - that’s the light-detecting area at the back of the eye.
Being able to view it up close may ultimately help clinicians detect the early signs of age-related macular degeneration, or AMD. One of the most common causes of sight loss in the over 50s, AMD involves the progressive death of light-sensitive cells in a key part of the retina. So how does the UCD group get that picture?
“We try to image the retina in the living eye as well as we can,” explains Dr Vohnsen, who originally comes from Denmark and is a Stokes Lecturer at UCD School of Physics. “We send a laser beam into the eye, using the pupil as a pivot point, then the eye focuses the beam and we scan line by line across the retina.”
By detecting the small amount of light that is reflected back, the approach rapidly builds up a high-resolution image, explains Dr Vohnsen.
At the moment, the usual test for signs of AMD looks for a loss of visual function, but imaging the eye may be able to instead pick up structural changes or ‘bumps’ that can appear on the retina in early AMD, notes Dr Vohnsen. So far the team has been testing out the approach on their own eyes and they can see light-sensitive cells in the retina.The goal is to capture images from an important section of the retina called the fovea.
“We have patented a technology that can reduce the size of the focal spot so it can be better matched to the fovea,” explains Dr Vohnsen. His group, which receives funding from Enterprise Ireland and Science Foundation Ireland, is also looking at ways to image collagen in the cornea, the clear pane over the front of the eye.
Surgeons can carry out corrective procedures that remove some of the corneal tissue, and the imaging technology could ultimately allow them to monitor the corneal collagen in real time, according to Dr Vohnsen. That work is currently being carried out in preclinical models, but in collaboration with consultant ophthalmologist Mr Arthur Cummings, the hope is to translate the imaging technology to the clinic.
The move from bench to industry and bedside is a key focus for Dr Vohnsen, who also set up a Taught Masters Programme in NanoBioScience when he moved to UCD in 2008. “The students learn about optics, nanophotonics, molecules, lasers and innovation,” he explains. “And we would like them to apply their research.”
Dr Brian Vohnsen was interviewed by freelance journalist Dr Claire O'Connell
