Wide-field retinal imaging system
A retinal imager for imaging a retina of an eye includes an illumination source operable to generate illumination light and a beam splitter operable to receive the illumination light and direct the illumination light along an optical axis. The retinal imager also includes a field lens disposed along the optical axis and an objective lens disposed along the optical axis and operable to contact a cornea of the eye. An aerial image is formed adjacent to the field lens. The retinal imager further includes an image sensor and one or more lenses disposed along the optical axis between the beam splitter and the image sensor. The one or more lenses are operable to form a sensor image at the image sensor.
1. A hand held retinal imager including image guided optical coherence tomography (OCT), the hand held retinal imager comprising:
an illumination source operable to generate illumination light;
a beam splitter operable to receive the illumination light and direct the illumination light along an optical axis;
a field lens disposed along the optical axis;
an objective lens disposed along the optical axis and operable to contact a cornea of an eye, wherein the objective lens is operable to inject the illumination light into the eye as an illumination ring;
an entrance pupil, wherein the entrance pupil and the illumination ring are located at different positions along the optical axis;
an image sensor;
an imaging lens group disposed along the optical axis between the beam splitter and the image sensor, wherein the imaging lens group is operable to form a sensor image at the image sensor;
a second beam splitter positioned within the imaging lens group; and
an OCT beam train optically coupled to the second beam splitter.
2. The hand held retinal imager of claim 1 further comprising a housing having a grip operable to be held by a hand of a user.
3. The hand held retinal imager of claim 1 wherein an aerial image is formed adjacent to the field lens.
4. The hand held retinal imager of claim 3 wherein the aerial image comprises an object for the sensor image at the image sensor.
5. The hand held retinal imager of claim 3 wherein the aerial image is formed between the field lens and the beam splitter.
6. The hand held retinal imager of claim 3 wherein the objective lens is further operable to receive reflected light from a retina and the aerial image is formed by the reflected light.
7. The hand held retinal imager of claim 1 wherein the objective lens comprises a single element objective lens.
8. The hand held retinal imager of claim 7 wherein the illumination light is injected into the eye through the single element objective lens.
9. The hand held retinal imager of claim 1 wherein the OCT beam train comprises a micro-electromechanical system (MEMS) mirror.
10. The hand held retinal imager of claim 9 where a pupil is formed on the MEMS mirror.
11. The hand held retinal imager of claim 1 wherein a single fiber is utilized to transmit and receive light propagating along the OCT beam train.
12. The hand held retinal imager of claim 1 wherein the sensor image comprises a central area.
13. The hand held retinal imager of claim 12 wherein the central area is circular.
14. The hand held retinal imager of claim 12 wherein the sensor image further comprises an annular area surrounding the central area.
15. The hand held retinal imager of claim 14 wherein a periphery of the central area forms a common border with an inner periphery of the annular area.
16. The hand held retinal imager of claim 12 wherein the sensor image further comprises three azimuthal segments.
17. The hand held retinal imager of claim 16 wherein the central area is defined by a first field of view of a first width and each of the three azimuthal segments is defined by a second field of view extending from the first width to a second width.
18. The hand held retinal imager of claim 17 wherein the first width is 15° and the second width is 22.5°.