Current treatments for glaucoma aim to lower the pressure of fluid within the eye. However, many people who receive these treatments still go on to lose their vision.

While lowering pressure is essential to preventing the death of retinal ganglion cells – the cells in the retina affected by glaucoma – the exact reason they die is still not known.

“We know we are missing something very important about the disease,” says CERA Head of Visual Neurovascular Research Dr Luis Alarcon-Martinez.

Both he and CERA Head of Visual Neuroscience Dr Anna Wang are looking into these cells in remarkable detail to discover exactly what factors are causing this cell death.

The retina is a thin layer of light-sensitive nerve tissue at the back of our eyes made up of several different cell types, arranged in layers. 

“You could picture it a bit like a layer cake,” Dr Wang says. 

“The cells on the top layer convert light into electrical signals that reach the retinal ganglion cells at the bottom layer.”

Retinal ganglion cells send information to the brain through long axons, which make up the optic nerve.

In glaucoma the death of these retinal ganglion cells disrupts this vital communication and eventually leads to vision loss.

To understand more about how these cells die they are using Dr Alarcon-Martinez’s pioneering two-photon microscopy method – an advanced imaging technique allowing researchers to see living tissue at a scale not possible with other microscopes.

Different views

Each researcher is using the technique in different ways.

Dr Wang is aiming to understand the different types of retinal ganglion cells and see if they are affected differently in glaucoma.

“For instance, we might discover that a type of retinal ganglion cell reacts in a specific way to moving objects and is more likely to be damaged in glaucoma,” Dr Wang says.

“This information could be used as an important tool for testing patients.”

Dr Alarcon-Martinez is researching blood flow in the retina to understand the impact that may have in glaucoma.

“Nerve cells are always getting or using some levels of energy, which is why blood flow is so important to the retina, 

the optic nerve and the brain,” says Dr Alarcon-Martinez.

Dr Alarcon-Martinez is collaborating with Professor Adriana Di Polo from the University of Montreal, who is a global leader in understanding the mechanisms behind glaucoma.

Together they previously used two-photon microscopy to discover unseen structures that communicate to regulate blood flow between cells in the retina, optic nerve and brain, called nanotubes.

If nanotubes are broken, the blood flow is disrupted.

“We are now seeing the importance of this process to diseases, including glaucoma,” says Dr Alarcon-Martinez.

Dr Alarcon-Martinez’s ongoing work is supported by Fighting Blindness Canada, Alcon Research Institute, Australian Vision Research, Perpetual, Sir Edward Dunlop Medical Research Foundation and the CERA Foundation. 

Dr Anna Wang is supported by the DHB Equity Fellowship for Excellence in Vision Research and a Jack Brockhoff Foundation Early Career Medical Research Grant. 

This story was originally published in Share our vision: Annual Review 2024.