Abstract: Aspects of the invention are directed to apparatus and methods for automatically setting a power level of light emitted by a light source; illuminating a retina of a patient with the light emitted by the light source; receiving, at a sensor, light reflected from the retina of the patient; providing a signal based upon the received light; determining whether the signal meets one or more signal quality criteria; automatically setting a second power level of light emitted by the light source; and repeating the steps of illuminating the patient's eye, receiving reflected light, providing the signal, and determining whether the signal meets the signal quality criteria. In some embodiments, setting the second power level is performed in response to determining whether the signal meets the signal criteria. In still other embodiments, the method comprises selecting an operating power based upon the signal quality criteria.

Abstract: An apparatus for registering a series of video images of a spherical or quasi-spherical surface subject to movement relies on projecting at least four diffusely scattering spots of light on the surface in a preferred angular manner, and monitoring the movement of images of the light spots relative to a reference image of the light spots.