Method and Device for Laser Ray Tracing Measurement of Intraocular Distances and Structures

A device for laser ray tracing measurement of intraocular distances and structures in an eye, comprising:

• a laser configured to emit a laser beam of a wavelength suitable for ray tracing;
• a pair of acousto-optical deflectors comprising a first deflector configured to deflect said laser beam in a first plane containing an optical axis and a second deflector configured to deflect said laser beam in a second plane containing the optical axis and orthogonal to the first plane, each acousto-optical deflector in the pair having an entrance aperture and an exit aperture and each-positioned along a path of the laser beam whereby effective centers of deflection thereof substantially coincide;
• a first driver with an output operably connected to the first deflector, and a second driver with an output operably connected to the second deflector;
• a first frequency generator with an output connected to the first driver, and a second frequency generator with an output connected to the second driver;
• a telescope and a collimating lens placed sequentially in optical alignment with the centers of deflection of said pair of acousto-optical deflectors;
• a first beam splitter placed in the path of the laser beam to the human eye and of the back scattered laser radiation from the eye;
• a second beam splitter placed after the first beam splitter on the path to the eye;
• a basic optometric channel placed with an optical axis bent to the eye by the second beam splitter, said basic optometric channel containing a target, a system of positioning and alignment of the device, and means for measuring a topography of the cornea and wavefront characteristics of the eye;
• and
• a processing unit with a display, said processing unit in operable communication with said laser, with said frequency generators, and with said basic optometric channel;
• wherein:
• the laser beam propagation zone is divided into an internal zone and an external zone, of which the internal zone is configured for ray tracing the eye with the laser beams parallel to the optical axis while the external zone is configured for oblique ray tracing of the eye;
• a set of optical elements is placed in the external zone directing the probing laser beams at skew angles;
• the structure of each of said first frequency generator and said second frequency generator comprises:
• a first oscillator of a first frequency, a second oscillator of a second frequency, a third oscillator of a third frequency, a fourth oscillator of a fourth frequency, and a combination-frequency unit,
• said first frequency and said second frequency having a first frequency shift between them that defines a spatial splitting in a first double-beam,
• said third frequency and said fourth frequency having a second frequency shift between them that defines a spatial splitting in a second double-beam,
• said combination-frequency unit combining said first frequency shift and said second frequency shift as a difference therebetween or as a sum thereof, and
• a configuration of the first frequency generator and the second frequency generator enabling a mode of all oscillators functioning simultaneously or a mode of a single functioning oscillator;
• a coherent detector is placed on the path of the back scattered laser radiation after the first beam splitter with an aperture in front of said coherent detector;
• a low-pass filter is placed at the output of the coherent detector, said low-pass filter being connected to the processing unit;
• and
• a phase discriminator is placed after the low-pass filter with its signal input connected to the output of said low-pass filter, and its reference input having when-enabled connections to the combination-frequency units of said first frequency generator or said second frequency generator, the output of said phase discriminator connected to said processing unit;
• said processing unit in its connections with said first frequency generator and said second frequency generator are configured to provide measurement in said first plane and said second plane separately to:
• enable the connection of said first frequency, said second frequency, said third frequency and said fourth frequency from said first frequency generator to said first driver, the connection of a single frequency from said second frequency generator to said second driver, the connection of the combination frequency from said first frequency generator to the reference input of said phase discriminator when providing the measurement in the first plane, and
• enable the connection of said first frequency, said second frequency, said third frequency and said fourth frequency from said second frequency generator to said second driver, the connection of a single frequency from said first frequency generator to said first driver, the connection of the combination frequency from said second frequency generator to the reference input of said phase discriminator when providing the measurement in the second plane.