Single-Camera Focus-Based Localization of Intraocular Devices

Future retinal therapies will be partially automated in order to increase the positioning accuracy of surgical tools. Proposed untethered microrobotic approaches that achieve this increased accuracy require localization information for their control. Since the environment of the human eye is externally observable, images can be used to localize the microrobots. In this paper, the common methods of ophthalmoscopy assuming a single stationary camera are examined and compared with respect to their imaging and localizing properties on a schematic model of the human eye. The first algorithm for wide-angle intraocular localization based on indirect ophthalmoscopy is presented, and its sensitivity with respect to uncertainties in the parameters of individual eyes is estimated. A calibration technique to account for these uncertainties is proposed, and the localization algorithm is validated with experiments in a model eye.