A glowing glimpse of Parkinson's

A new imaging technique makes the sick and dying retinal cells in patients’ eyes glow – and could enable optometrists to pick up conditions from Parkinson’s disease to macular degeneration (MD).

The technique is known as the detection of apoptosing retinal cells (DARC) in vivo imaging.

University College London vision neuroscientist, Professor Maria Cordeiro, has just found that DARC, used alongside optical coherence tomography, is able to catch the earliest signs of Parkinson’s disease in the retina of mice, according to a paper published in the journal Acta Neuropathologica Communications.

She told OT that: “These changes occur earlier than the changes in the brain.”

The technique paired a protein, Annexin A5, with a fluorescent tag. The Annexin A5 binds to stressed or dead cells, and when this substance is injected into the eye, white spots highlight any degeneration.

As well as showing the first signs of the onset of the disease, the retina of the mice also showed the earliest response when a successful treatment was given.

Professor Cordeiro explained that: “A big problem at the moment is that there are very few biomarkers [of Parkinson’s disease] available that mean we can non-invasively monitor it. That means that trials have to be very long.

“With this technique, we can see the change much more quickly, if the technique is working,” she emphasised.

The team is now conducting a Phase I clinical trial using the imaging in patients, and a Phase II trial will begin shortly, Professor Cordeiro said.

The technique had applications beyond Parkinson’s disease, with the researchers also looking at its potential to catch MD at an earlier stage than current screening methods. They were also developing a way to deliver the fluorescent substance into the eye using an eye drop.

“In the long run, we see this technique being available for use in optometrist clinics, for them to do such screening,” she highlighted.