Intra Ocular Vision Aid (IOS)
Background
Severe corrosion of the eye , intraocular infections (uveitis), or injuries caused by explosions may cause dullness of the cornea or shrinkage of the anterior part of the eye. Although the retinal function is often still intact, this dullness or shrinkage leads in many cases to blindness of the affected person, as the light is perturbed on its way to the retina.
The goal of this project is the design of an intraocular vision aid which is overcoming the disturbed light path, thus yielding to an improved visual acuity of the patient. However, a precondition for the usability of such a vision aid is the intact function of the retina.
Function Principle
Images of the field of view of the patient are continuously captured by a pair of glasses attached CMOS-camera. The images are transferred to an implanted micro display via a wireless infrared communication link. An optical setup between the encapsulated micro display and the retina is imaging the displayed information to the retina.
Spatial dependent information distribution
The limited display resolution available inside the eye does not allow a linear distribution of the information onto the retina: a linear pixel distribution over the whole retinal area would result in an insufficient spatial resolution and thus vision. The concentration of the information onto a small central area of the retina on the other hand will result in a tunnel view of the patient. By introducing a nonlinear spatial distribution of the displayed information it is possible to build a trade-off between the two mentioned linear problematics.
Psychophysical Simulation
Psychophysical analysis of optimal information distribution schemes onto the retina made the design of a simulator necessary. The field of view of a pro-band is captured, processed, based on the distribution scheme to be evaluated, and imaged via an external video display. Eye tracking of the test person accounts for a correct imaging of the views scene with the goal to exactly simulate an intraocular vision aid.
Optic Design
The limited display resolution inside the eye and the complex imaging function requires the need of a special optic design for the intraocular vision aid. With a combination of a shading mask together with a micro lens it is possible to realize the desired image distribution.
Project
Intra Ocular Vision Aid (IOS)