Ophthalmic examination and disease management with multiple illumination modalities
Imaging various regions of the eye is important for both clinical diagnostic and treatment purposes as well as for scientific research. Diagnosis of a number of clinical conditions relies on imaging of the various tissues of the eye. The subject technology describes a method and apparatus for imaging of the back and/or front of the eye using multiple illumination modalities, which permits the collection of one or more of reflectance, spectroscopic, fluorescence, and laser speckle contrast images.
1. A method of imaging a region of tissue of an eye, the method comprising:
configuring an ophthalmic imaging device to achieve a desired imaging modality by adjusting one or more optical assemblies, two or more illumination sources, or one or more image acquisition parameters, wherein the two or more illumination sources include a coherent light source and an incoherent light source;
illuminating a first region of interest of the eye using one of the illumination sources;
acquiring a first image by capturing light coming from the first region of interest based on the image acquisition parameters, wherein the first image is one of a laser speckle contrast image, spectroscopic image, reflectance image, or fluorescence image;
reconfiguring the ophthalmic imaging device by adjusting the one or more optical assemblies, the two or more illumination sources, or the one or more image acquisition parameters;
illuminating a second region of interest, the second region of interest at least partially overlapping the first region of interest;
acquiring a second image by capturing light coming from the second region of interest, wherein second image is one of a laser speckle contrast image, spectroscopic image, reflectance image, or fluorescence image different from the first image;
and
processing the first image and the second image.
2. The method of claim 1 , further comprising immobilizing an ophthalmic imaging device with respect to a subject's eye.
3. The method of claim 1 , wherein the ophthalmic imaging device is handheld and the method comprises immobilizing the ophthalmic imaging device by resting or pressing against a subject's face or eye.
4. The method of claim 1 , comprising: immobilizing, using eyeglasses, goggles, a helmet, or other accessory, the ophthalmic imaging device with respect to a subject's head or eye.
5. The method of claim 1 , comprising: immobilizing, using a chin rest, a subject's head or eye.
6. The method of claim 1 , comprising: generating a virtual object by the ophthalmic imaging device.
7. The method of claim 1 , wherein the image acquisition parameters include at least one of exposure time, gain, pixel sensitivity, number of images, frame rate, timing sequence, pixel resolution, pixel area, or image magnification.
8. The method of claim 1 , wherein reconfiguring the ophthalmic imaging device comprises switching from the coherent light source to the incoherent light source, or switching from the incoherent light source to the coherent light source.
9. The method of claim 1 , wherein processing the first image or the second image comprises calculating laser speckle contrast values for pixels associated with the region of interest, wherein the calculated laser speckle contrast values are based on a pixel's neighborhood of pixels in spatial or temporal domains.
10. The method of claim 1 , wherein the processing the first image and the second image comprises generating a compound image based on at least two of laser speckle contrast images, spectroscopic images, reflectance images, or fluorescence images.
11. The method of claim 10 , wherein at least one of the first image and the second image comprises a laser speckle contrast image.
12. The method of claim 1 , further comprising fixating, with a gaze fixation mechanism of the ophthalmic imaging device, a contralateral, non-imaged eye's gaze on a specified physical or virtual target.
13. The method of claim 12 , further comprising varying a location of the physical or virtual target during imaging to facilitate acquisition of images of different regions of the eye.
14. The method of claim 12 , further comprising performing one or more calculations for operation of the gaze fixation mechanism, wherein the one or more calculations include calculations pertaining to location identification of an intended target of gaze fixation and location identification of the virtual or physical target object.
15. The method of claim 1 , wherein one of the first image or the second image is a reflectance image and the other of the first image or the second image is a laser speckle contrast image.
16. The method of claim 1 , wherein one of the first image or the second image is a spectroscopic image and the other of the first image or the second image is a laser speckle contrast image, the method further comprising processing the first image and the second image to distinguish between veins and arteries of the eye.