Serendipity in the deep

How a chance discovery saw a UK biological scientist create a new way of assessing macular pigment density

Eye with an octopus reflected

In the shadowy depths of the ocean tentacled creatures roam through a monochromatic world.

It was through observing the vision of these sea-dwellers that University of Bristol biological scientist Dr Shelby Temple made a discovery that could transform the way optometrists assess macular pigment levels. 

“I didn’t set out to solve this problem. It was thrust upon me, somewhat serendipitously,” Dr Temple explained.

While researching the limits of polarised vision of octopuses and cuttlefish, Dr Temple realised that he could see the outline of the polarized images that he was presenting to cephalopods on a specially modified LCD screen.

The image that Dr Temple perceived when he looked at the polarised light is known as Haidinger’s brushes, a phenomenon that is generated inside the eye when polarised light interacts with the macular pigments. 

“When viewed against a white background Haidinger's brushes look like a faint yellow bow tie,” Dr Temple shared.  

Following a hunch

Dr Temple explained that there was some evidence that how clearly humans saw this effect was linked to macular pigment density. 

He decided that the first thing he could do to test this concept was to find out whether the ability to see the effect varied between individuals – which proved to be the case through experiments conducted in 2014. 

Subsequent testing found a good correlation between macular pigment density as estimated by a device developed through the research and levels recorded by “gold-standard” technology already on the market. 

Dr Temple’s work has seen him named as the 2017 Innovator of the Year by the Biotechnology and Biological Sciences Research Council. 

In 2016, Dr Temple received £500,000 in funding from Innovate UK. This investment resulted in the launch of Azul Optics Ltd, a Bristol-based start-up that is commercialising the device. Azul Optics has since secured an additional £310,000 in private investment.

An “elegantly simple” test

To use the pioneering technology, the patient looks into a small circle of light through a device placed on their head and sees the Haidinger’s brushes effect. The optometrist then adjusts the light to make it harder and harder for the patient to make out the phenomenon. 

Dr Temple explained that the threshold at which the patient stops seeing the effect is an indication of the macular pigment density.

“If your macular pigments are very high, then you would see the pattern more easily to start with and you can see it to a lower setting on our device,” Dr Temple shared. 

“Someone with lower macular pigment would have a harder time seeing Haidinger’s brushes and they stop seeing it much earlier,” he elaborated. 

Dr Temple hopes that the device he has developed through Azul Optics will be available for early adopters over the next 12 to 18 months. Large scale trials of the device are underway at the Macular Pigment Research Group in Ireland. 

“We are quite lucky. The technology is elegantly simple so right now we are well into the design of the actual device, its casing and the optics,” Dr Temple highlighted.

A personal commitment

The research could ultimately lead to a simple, low-cost test that optometrists can use to determine an individual’s risk of developing health conditions that have been linked to low macular pigment levels, such as age-related macular degeneration (AMD).

Dr Temple told OT  that working to reduce the impact of AMD is a cause that is close to his heart. 

“My grandmother had AMD. Seeing her suffering – not being able to read or look at pictures of her loved ones anymore – that was a real eye-opener,” Dr Temple shared. 

“This does affect people in a serious way, particularly when they are at an age where they are already quite fragile,” he concluded. 

Image credit: Dr Shelby Temple