Systems and methods for applying and monitoring eye therapy
Devices and approaches for activating cross-linking within corneal tissue to stabilize and strengthen the corneal tissue following an eye therapy treatment. A feedback system is provided to acquire measurements and pass feedback information to a controller. The feedback system may include an interferometer system, a corneal polarimetry system, or other configurations for monitoring cross-linking activity within the cornea. The controller is adapted to analyze the feedback information and adjust treatment to the eye based on the information. Aspects of the feedback system may also be used to monitor and diagnose features of the eye. Methods of activating cross-linking according to information provided by a feedback system in order to improve accuracy and safety of a cross-linking therapy are also provided.
1 . A system for activating a cross-linking agent applied to a cornea of an eye, comprising:
a light source including a light emitting diode for emitting a non-ablative photoactivating light, the light source emitting linearly polarized light or a beam of light capable of being filtered to pass linearly polarized light;
a digital micromirror device (DMD) including a plurality of mirrors arranged in a matrix, the plurality of mirrors configured to selectively reflect the photoactivating light from the light source to provide a pixelated illumination to be directed to a cornea of an eye, the pixelated illumination including pixels defined by the mirrors in the DMD;
one or more optical elements positioned to direct the pixelated illumination from the DMD to the cornea;
a controller configured to control the DMD to programmatically select which of the mirrors reflect the photoactivating light to provide the pixelated illumination to a selected region of the cornea, wherein, at one particular instant in time, the pixelated illumination is defined by a two-dimensional array of the pixels, the controller being configured to control the light source to determine a duration for the pixelated illumination to generate cross-linking activity in the selected region of the cornea; and
a feedback system configured to provide the controller with feedback information for controlling the DMD, the feedback system including an eye-tracking system having a video camera,
wherein the feedback system is further configured to measure changes in biomechanical strength or stiffness in response to a corneal deflection, and
wherein the controller is further configured to determine an amount of cross-linking based on the feedback information, and controlling the light source comprises modulating the DMD spatially and temporally at least partially based on the determination.
2 . A system for activating a cross-linking agent applied to a cornea of an eye, comprising:
a light source including a light emitting diode for emitting a non-ablative photoactivating light, the light source emitting linearly polarized light or a beam of light capable of being filtered to pass linearly polarized light, wherein the light source is configured to be applied with a power of between 30 mW and 1 W and deliver the photoactivating light so that a dose between 5 J/cm 2 and 30 J/cm 2 can be absorbed by the cornea;
a digital micromirror device (DMD) including a plurality of mirrors arranged in a matrix, the plurality of mirrors configured to selectively reflect the photoactivating light from the light source to provide a pixelated illumination to be directed to a cornea of an eye, the pixelated illumination including pixels defined by the mirrors in the DMD;
one or more optical elements positioned to direct the pixelated illumination from the DMD to the cornea;
a controller configured to control the DMD to programmatically select which of the mirrors reflect the photoactivating light to provide the pixelated illumination to a selected region of the cornea, wherein, at one particular instant in time, the pixelated illumination is defined by a two-dimensional array of the pixels, the controller being configured to control the light source to determine a duration for the pixelated illumination to generate cross-linking activity in the selected region of the cornea; and
a feedback system configured to provide the controller with feedback information for controlling the DMD, the feedback system including an eye-tracking system having a video camera,
wherein the feedback system is further configured to measure changes in biomechanical strength or stiffness in response to a corneal deflection, and
wherein the controller is further configured to determine an amount of cross-linking based on the feedback information, and controlling the light source comprises modulating the DMD spatially and temporally at least partially based on the determination.
3 . The system of claim 2 , further comprising an applicator configured to apply the cross-linking agent to the cornea, wherein the cross-linking agent includes Riboflavin.
4 . The system of claim 2 , wherein the light source emits ultraviolet light.
5 . The system of claim 2 , wherein the one or more optical elements includes an objective lens, and the controller is further configured to generate one or more signals to control a focal plane of the objective lens and thus the depth within the cornea that the pixelated illumination is focused.
6 . The system of claim 5 , further comprising an objective lens motor configured to adjust the location of the objective lens relative to the mirror array, the controller being configured to adjust the focal plane of the objective lens via the objective lens motor to provide the pixelated illumination in three dimensions to a plurality of different planes between a corneal surface of the cornea and a mid-depth region within the corneal stroma of the cornea.
7 . The system of claim 2 , wherein each pixel defining the pixelated illumination is associated with a respective one or more mirrors of the DMD.
8 . The system of claim 2 , wherein the controller is configured to control the DMD to programmatically select which of the mirrors reflect the photoactivating light to direct the pixelated illumination to the selected region of the cornea according to a particular pattern.
9 . The system of claim 8 , wherein the controller is configured to programmatically control the DMD to modify which of the mirrors reflect the photoactivating light to adjust the pixelated illumination and continue directing the pixelated illumination to the selected region of the cornea according to the particular pattern.
10 . The system of claim 9 , wherein the eye-tracking system includes a camera configured to provide images indicating the movement of the eye, and the controller is further configured to determine the movement of the eye based on the images.
11 . The system of claim 8 , wherein the power or the duration for the pixelated illumination determine a dose of photoactivating light to generate cross-linking activity in the selected region of the cornea according to the particular pattern, and the controller is further configured to programmatically modify, during delivery of the dose, which of the mirrors of the DMD reflect the photoactivating light to direct the pixelated illumination to the selected region of the cornea according to the particular pattern.
12 . The system of claim 2 , wherein the controller is configured to control the DMD to programmatically select any combination of the mirrors to reflect the photoactivating light to provide the pixelated illumination according to a desired pattern.
13 . The system of claim 2 , wherein the controller is configured to control the DMD to programmatically select the mirrors to reflect the photoactivating light to provide the pixelated illumination according to a non-circular pattern.
14 . The system of claim 2 , wherein the controller is configured to control at least one of the light source or the one or more optical elements to generate a three-dimensional pattern of the photoactivating light based on the pixelated illumination extending from a surface of the cornea to a depth in a stroma of the cornea.
15 . The system of claim 2 , further comprising a head restraint device for restraining a head associated with the eye.
16 . The system of claim 2 , further comprising an interferometer configured to measure a surface shape of the cornea including two quarter-wave plates configured to convert linearly polarized light to circularly polarized light, by receiving a signal beam, the interferometer having a polarizing mask capable of changing following exposure to the signal beam.
17 . The system of claim 2 , wherein modulating the DMD comprises adjusting the two-dimensional array of the pixels.