Intraocular visual aid
Intraocular visual aid (IOS)
Background
Corneal opacities or shrinkage of the anterior segment of the eye following severe eye burns, severe intraocular inflammation or blast injuries still lead to blindness in many cases, despite the further development of microsurgical techniques. However, most of these patients still have an intact and fully functional retina.
The aim of this project is to develop an intraocular visual aid (IOS) that bridges opacities in the anterior segment of the eye and restores at least orientation vision to the patient. The prerequisite for this is intact retinal function.
How it works
The patient receives an image of the environment via a CMOS camera built into a pair of glasses, which is sent to a display via wireless signal transmission. This display is embedded in a silicone diaphragm and implanted in the eye at the level of the retina. An optical system located between the display and the retina ensures that the display information is optimally projected onto the retina.
Location-dependent information distribution
The limited information density of the intraocular microdisplay does not allow the image information it provides to be displayed linearly on the retina: A linear distribution of information over the entire retina would realize an unacceptable resolving power, whereas a concentration of information on a small retinal area (e.g. that of sharp vision) would result in a tunnel effect for the patient. By introducing a non-linear distribution of different magnifications, it is possible to avoid the two problems described above.
Psychophysical simulation
A simulator for psychophysical analysis was created to evaluate optimal information distribution strategies. An image sequence recorded of the observed environment is coupled into the eye via a video display in accordance with the distribution algorithms to be investigated. By automatically determining the direction of gaze of the test person, it is ensured that the image information is displayed in the same position in the healthy eye as with an intraocular visual aid.
Optics design
The limited dimensions of the eye and the complexity of the imaging function require the design of special imaging optics for the visual aid. It is possible to realize the desired function through a shadow casting arrangement in combination with an imaging lens.
Projects
Intraocular visual aid (IOS)