TNO retinal camera detects oxygen deprivation

18 Oct 2023

Illumination with specific patterns and colors reveals diagnostic information.

Dutch research center TNO has announced the development of a new retinal camera platform intended to allow easier diagnosis of eye disease.

In particular the platform should ultimately assist early detection of diabetic retinopathy, a condition where high blood sugar levels cause damage to the fragile blood vessels in the retina through oxygen starvation.

The TNO platform will measure oxygen saturation in the blood vessels of the retina, and the lab has also developed a model of the human eye to allow validation of the camera. Its device was presented at the congress of Euretina, the European Society of Retina Specialists, earlier in October 2023.

Together with the Rotterdam Ophthalmological Institute and the Leiden Centre for Human Drug Research, TNO is working on an approach allowing quantitative retinal imaging, in which the retina is illuminated with line patterns of specific colors so as to image both the level and distribution of retinal oxygen.

"TNO is also developing an scanning laser ophthalmoscope (SLO) system in close cooperation with the Vrije Universiteit Amsterdam and Heidelberg Engineering," commented the center. "Using a very fast scanning laser, with multicolored light, it measures the oxygen saturation in the retinal blood vessels."

As well as allowing diagnosis of eye diseases such as diabetic retinopathy, the same approach could also reveal diagnostic information about cardiovascular diseases and brain disorders including Parkinson's and Alzheimer's, through study of the eye. Evidence of amyloid plaque build-up in the retina is known to be a biomarker for neurodegenerative disease, and can be spotted through hyperspectral imaging techniques .

Accurate imaging and rapid diagnosis

TNO commented that validation of new instruments in ophthalmology is challenging because the retina is not accessible physically, and the center has developed a novel model eye to validate its retinal cameras and their oxygen measurement function.

This model accurately mimics a blood vessel in the human eye, and involves authentic human blood flowing through a small artificial blood vessel into a layered retina with the optical and geometric properties of a real eye, according to TNO. The oxygen saturation in the blood is then adjusted by means of a miniature heart-lung machine.

The new devices build on TNO's research into retinal imaging, which includes collaboration with Dutch start-up RetinaScope in which TNO holds a 20 percent stake. RetinaScope, founded in 2018, aims to develop an affordable, portable fundus camera, to improve public health screening for eye diseases. The RetinaScope Plus hand-held instrument was launched in 2022.

A key element of improved diagnosis will be rapid analysis of the data collected by these cameras, with cloud-based AI assessment expected to be a key element of the health screening process. RetinaScope is collaborating with a number of companies to develop bespoke retina photography software to process the imaging data.

"The camera will soon be easy to link to this software, removing an important barrier for patients when it comes to having their eyes checked," commented the company.