Placement of the gas catheter next to the macula and the optical nerve.

Tackling Oxygen Deficiency in the Eye

Steinbeis experts develop technology for treating eye condition

The eye has the highest metabolic rate of all organs and thus places the highest oxygen demands on the body. It also has the highest blood circulation rate of all organs, which means that if circulatory problems occur and there is a shortage of oxygen, this can have a cataclysmic impact on the eyeball. Within hours, a person can go blind. At the moment, there are no ways to successfully treat acute or chronic oxygen deficiency in the eyes. OcuTox, the Steinbeis Transfer Center, is a specialist in experimental vitreous and retinal surgery, and it is currently working on different ways to treat oxygen deficiency.

Previous attempts to treat this condition focused on the impact of oxygen deficiency or excessive concentrations, but they did nothing to regulate oxygen according to physiological requirements. The aim of the project at the Hechingen-based Steinbeis Transfer Center is therefore to remedy oxygen depletion in the outer retina or at least to regulate oxygen and thus develop successful treatment options. This should not only restore the oxygen supply to the outer retina but should also prevent excessive expression of the signal molecule VEGF, including its negative influences.

To remedy oxygen depletion or regulate oxygen according to physiological requirements, gas (oxygen, carbon dioxide, or other gases/mixtures) is channeled behind the eyeball into the orbital cavity. To do this, a thin, flexible catheter is inserted running from a reservoir of external oxygen to the area behind the eye. At the end of this tube is a double layer of synthetic membrane, which is aligned to run parallel to the sclerotic coat of the eye. The layer of synthetic material facing away from the eye does not allow oxygen to pass through, but the layer that does face the eye is permeable to gaseous oxygen. As a result, oxygen is allowed to escape and diffuse through the sclera and choroidea and pass into the retina.

The team of researchers plans to regulate the volume of oxygen emitted at the back of the eye by continuously monitoring concentrations in the eye. An oxygen sensor will be positioned in a similar way to the doublelayer membrane behind the retina (macula). This is because this is the most important section of the retina for clear vision and thus the place where there is highest demand for oxygen. Initial testing at the University Hospital of Tubingen has shown that retrobulbar application of gaseous oxygen can increase the concentration of oxygen in the eye. The semipermeable membrane and the oxygen sensor could be positioned behind the eyeball or in the vitreous humor. The electronic controls need an associated power supply and an oxygen reservoir; this can be located outside the eye, for example as an add-on to spectacles or behind the ear, similar to a hearing aid.

There are approximately 2.6 million patients in Germany alone who could benefit from such a device, or at least could have. The invention has already been registered for patents. The experts at the OcuTox Steinbeis Transfer Center are currently looking for partners from industry and sponsors so they can develop the external part of the device and the control unit together.

Contact

Prof. Dr. Ulrich Schraermeyer
Steinbeis Transfer Center OcuTox (Hechingen)