BACKGROUND

Prior approaches to corneal topography can be less than ideal in at least some instances. For example, many commercially available corneal topography systems are larger than would be ideal, which can make it somewhat cumbersome and expensive for health care professionals who need to provide dedicated space for these systems, and such devices may not be readily integrated into an exam room in at least some instances. Although efforts have been made to decrease the size of corneal topography systems, such devices have provided less than ideal results in at least some instances. For example, although smart phone based corneal measurement systems have been proposed, in at least some instances such devices may not measure corneal topography and may merely provide qualitative rather than quantitative information in at least some instances. Alignment of the eye with the corneal topography system can be helpful for obtaining accurate corneal topography measurements, and at least some of the prior approaches may have less than ideal alignment and accuracy in at least some instances.

Prior art corneal topography systems (which may be connected to a laptop computer or a desktop computer) project an image of Placido rings off of a cornea of a human eye and into a digital imaging sensor (or one or more digital imaging sensors). Some prior art systems are affixed to a desktop computer or may attach to a laptop computer, each of which may be typically running a Windows operating system or a MAC operating system. Prior art desktop-based or laptop-based corneal topography systems may use an image sensor and a custom, proprietary imaging lens system designed to suit the desired parameters of the instrument including field of view, focal length, and desired image magnification to maximize use of the target commercial image sensor for its intended purpose. The prior art desktop-based or laptop-based corneal topography systems do not require telescope optics because they utilize custom or proprietary imaging lens systems which provide the desired field of view and imaging magnification for the image sensor. For example, the Nidek OPD-III desktop topography systems may incorporate a Placido ring outside diameter of approximately 22 mm (horizontal)×19 mm (vertical), and a focal distance of approximately 70 mm (from the front lens of their imaging system).

A prior art corneal topography system attached to a smartphone is described in “An Accessible Approach to Corneal Topography” by Andre Luis Beling da Rosa (“Beling da Rosa publication”) in December of 2013. The article describes a clip-on device with three layers: 1) an illumination layer to provide illumination of concentric rings; 2) a support layer helping with the image captured using a lens and also with the diffusion and 3) the pattern layer (which gives a shape to projected patterns).FIG. 1illustrates a smartphone clip-on corneal topography device having three layers according to the prior art as shown in pages 40 and 41 of the Beling da Rosa publication. Another prior art corneal topography system attached to a smartphone is described in “Design And Development Of An Ultraportable Corneal Topographer For Smartphones As A Low Cost New Tool For Preventing Blindness Caused By Keratoconus” by Pinheiro et al (“Pinheiro publication”). This device includes a support cover, a printed circuit board with LEDs (light emitting diodes), an optical system for magnification, a cone with transparent and black concentric rings (principle of Placido) and a dome. However, the Pinheiro publication does not describe any details of an optical system.

Prior art corneal topography systems incorporated linear imaging, meaning that the prior art corneal topography systems projected an image in a straight line concentric with a ray entering an exact center of a Placido illumination system, which was perpendicular to a plane of concentric rings. However, none of these prior art corneal topography systems folded the beam back utilizing mirrors in an optical bench assembly or corneal topography optical housing.

In light of the above, improved corneal topography devices are needed that will overcome at least some of the aforementioned disadvantages of the prior art.

SUMMARY

In some embodiments, the mobile communication device-based corneal topography system and methods can provide decreased size and accurate topography measurements, such the system can be readily utilized by health care professionals. The topography system may comprise one or more components of a commercially available smart phone, such that the size, cost and complexity of the device can be decreased. These components can be configured to provide improved alignment, and can be arranged to facilitate measurements and improve alignment to improve the accuracy of measurements.

In some embodiments, the mobile communication device-based corneal topography system may be a small device that is easily transportable, which allows the system to be utilized in many locations. The mobile communication device-based corneal topography system may be mounted on a slit-lamp microscope. In some embodiments, the topography system comprises batteries and is configured to be powered by batteries to decrease size and increase mobility.

As a slit-lamp microscope mounted instrument, the mobile communication device-based corneal topography system may be able to capture data with high z-axis precision, and thus enable very precise optical power calculation. Thus, the mobile communication device-based corneal topography system's corneal power measurement accuracy may be equal to or better than prior art desktop-mounted corneal topography system, and much better than any existing hand-held or portable corneal topography system. In some embodiments, the mobile communication device-based corneal topography system may improve alignment significantly as compared to prior systems.

In some embodiments, a mobile communication device-based corneal topography system, an illumination system, a mobile communication device, and a corneal topography optical housing. The illumination system generates an illumination pattern (e.g., concentric rings) and generate reflections of the illumination pattern off a cornea of a subject. The mobile communication device includes an image sensor to capture an image of the reflected illumination pattern such as concentric rings, and the corneal topography is determined or calculated in response to the image. In some embodiments, the illumination pattern may be a predetermined illumination pattern. The corneal topography housing is coupled to both the illumination system and the mobile communication device and the corneal topography optical housing and supports and aligns the illumination system with the image sensor of the mobile communication device. In some embodiments, the illumination system is aligned along an axis of the centers of the illumination pattern. In some embodiments, the corneal topography optical housing includes an optical system having a Keplerian configuration to magnify the image of the reflected concentric rings being evaluated, so as to take maximum advantage of a sensor area of the image sensor of the mobile computing device and also to decrease an optical path length between the cornea of the subject and the image sensor. In some embodiments, the corneal topography optical housing may be mounted on a slit lamp microscope.

In some embodiments, a mobile communication device-based corneal topography system may include an illumination system, a mobile communication device, and a corneal topography optical housing. Although reference is made to a Placido illumination system, other illuminations can be used, such as discrete points of light from discrete light sources in a predetermined pattern, and rectilinear grids. The illumination system may generate an illumination pattern and also generate reflections of the illumination pattern off a cornea of a subject. The mobile communication device may include an image sensor to capture an image of the illumination pattern. In some embodiments, the corneal topography optical housing may include or house two or more mirrors, the two or more mirrors being positioned in an image path of the reflected illumination pattern image and located in front of a position of the image sensor of the mobile communication device. In some embodiments, the two or more mirrors may reduce a distance between the subject's cornea and the camera of the mobile communication device as compared to a system utilizing a corneal topography optical housing without the two or more mirrors. The reflective mirrors can decrease the overall size of the topography device and increase portability of the system. In some embodiments, the two or more mirrors in the image path of the reflected concentric ring image may reduce a distance between the subject's cornea and the camera of the mobile communication device to less than 165 millimeters (or 6.5 inches). In some embodiments, the two or more mirrors in the image path of the reflected concentric ring image may reduce a distance between the subject's cornea and the camera of the mobile communication device ranging between 50 millimeters to 165 millimeters (or 2 to 6.5 inches). In some embodiments, the two or more mirrors in the image path of the reflected concentric ring image may reduce a distance between the subject's cornea and the camera of the mobile communication device ranging between 165 millimeters to 204 millimeters (or 6.5 inches to 8 inches). In some embodiments, the corneal topography optical housing may have a length to keep a distance between the examiner's eye and the subject's eye between approximately 304 to 356 millimeters (or 12 and 14 inches). In some embodiments, the corneal topography optical housing may have a length to keep a distance between the examiner's eye and the subject's eye between approximately 254 to 381 millimeters (or 10 and 15 inches).

In some embodiments, a mobile communication device-based corneal topography system may include an illumination system, a mobile communication device and a corneal topography optical housing. The illumination system may generate an illumination pattern which may be reflected off a subject's cornea. The mobile communication device may comprise an image sensor to capture an image of the reflected illumination pattern. In some embodiments, a surface of the corneal topography optical housing that is coupled to the mobile communication device may be tilted with respect to a vertical axis. In some embodiments, a surface of the mobile communication device may be tilted with respect to the vertical axis to provide enhanced viewing of the reflected concentric rings image by an examiner or user. In some embodiments, the surface of the corneal topography optical housing may be tilted between 1 to 40 degrees with respect to the vertical axis. In some embodiments, the surface of the mobile communication device may be tilted between 0 to 40 degrees with respect to the vertical axis. In some embodiments, the surface of the corneal topography optical housing and/or a surface of the mobile communication device may be tilted between 0 to 10 degrees with respect to the vertical axis. In some embodiments, the optical axis of the illumination system and the corneal topography system may be tilted with respect to horizontal in order to provide ease of use and less eye strain on the subject being examined. In some embodiments, the optical axis may be inclined downward moving away from the eye and the display or screen of the mobile communication device may be inclined upward as viewed by a user.

In some embodiments, a mobile communication device-based corneal topography system may include an illumination system, a mobile communication device and/or a corneal topography optical housing. The illumination system may generate an illumination pattern which may be reflected off a cornea of a subject. The mobile communication device may comprise an image sensor to capture the image of the reflected illumination pattern. In some embodiments, the corneal topography optical housing may include or house two or more mirrors, where the two or more mirrors may be located in an image path of the reflected illumination pattern image, and the angle of inclination of the two or more mirrors in an image path of the image results in the image of the reflected being tilted by an angular displacement with respect to the vertical axis to improve viewing of the reflected illumination pattern image by an examiner. In some embodiments, the angular displacement of the reflected illumination pattern image ranges between 0 and 15 degrees. In some embodiments, the angular displacement of the reflected illumination pattern image ranges between 0 and 40 degrees.

In some embodiments, a mobile communication device-based corneal topography system includes an illumination system, a mobile communication device, and a corneal topography optical housing. The illumination system may generate an illumination pattern, which may be reflected off a cornea of a subject and may also include an eye piece. The mobile communication device may include an image sensor that captures an image of the reflected illumination pattern. In some embodiments, the illumination system may be tilted upward by an angle of inclination with respect to a horizontal axis to provide more comfortable viewing by a subject being examined. In some embodiments, the angle of inclination of the illumination system and eye piece ranges from 0 to 7 degrees. In some embodiments, the angle of inclination of the illumination system and/or eye piece ranges from 0 to 15 degrees.

In some embodiments, a mobile communication device-based corneal topography system includes an illumination system, a mobile communication device, and a corneal topography optical housing. The illumination system may generate an illumination pattern, which may be reflected off a cornea of a subject. The mobile communication device may include an image sensor that captures an image of the reflected illumination pattern. In some embodiments, the illumination system, the corneal topography optical housing and the mobile communication device may be positioned to maintain a horizontal plane of alignment between a subject's eye and an examiner's eye during operation of the mobile communication device-based corneal topography system. In some embodiments, the corneal topography optical housing may be coupled to a slit lamp microscope. In some embodiments, the coupling of the slip-lamp microscope to the corneal topography optical housing provides +/−100 micron z-axis positional accuracy which results in +/−0.25 Diopter accuracy in calculating accurate corneal power.

In some embodiments, a mobile communication device-based corneal topography system includes an illumination system, a mobile communication device, and a corneal topography optical housing. The illumination system may generate an illumination pattern, which may be reflected off a cornea of a subject. The mobile communication device may include an image sensor that captures an image of the reflected concentric rings. In some embodiments, the corneal topography optical housing includes a first mirror and a second mirror positioned in an image path of the reflected illumination pattern image. In some embodiments, the first mirror may be a partial reflectance, partial transmittance mirror and a fixation light source may be located behind the first mirror. In some embodiments, the fixation light source may be positioned behind the partial reflectance, partial transmittance mirror to allow a subject being examined to focus on the fixation light source. In some embodiments, the system may further include an autorefractor and the second mirror is a partial reflectance, partial transmittance mirror. In some embodiments, the autorefractor may be positioned behind the second mirror to measure aberrations in the subject's by analyzing the reflected illumination pattern image.

In some embodiments, a mobile communication device-based corneal topography system includes a illumination system, a mobile communication device, and a corneal topography optical housing. The illumination system may generate an illumination pattern, which may be reflected off a cornea of a subject. The mobile communication device may include an image sensor that captures an image of the reflected illumination pattern. In some embodiments, the illumination system may comprise two or more proximity sensors which are located on opposite sides of a plastic cylinder that forms the illumination system. In some embodiments, the two or more proximity sensors may generate signals when a subject is being examined. In some embodiments, comparison circuitry may compare amplitudes of the generated signals received from the two or more proximity sensors and computer-readable instructions executable by one or more processors may receive the comparison of the amplitudes of the generated proximity sensor signals to determine whether a left eye or a right eye of a subject is being examined.

In some embodiments, a mobile communication device-based corneal topography system includes an illumination system, a first mobile communication device, and a first corneal topography optical housing. The illumination system may generate an illumination pattern, which may be reflected off a cornea of a subject. The first mobile communication device may include an image sensor that captures an image of the reflected image pattern the image sensor is located at a first position on a back surface of the first mobile communication device. In some embodiments, the first corneal topography optical housing may include two or more mirrors to create an image path to reflect the captured image into a center axis of the first position of the image sensor. In some embodiments, a second mobile communication device may include an image sensor, the image sensor being located in a second position on a second position on a back surface of the second mobile computing device. In some embodiments, the second corneal topography housing includes two or more mirrors to create an image path to reflect the captured image onto a center axis of the second position of the image sensor of the second mobile communication device.

In some embodiments, a mobile communication device-based corneal topography system includes an illumination system, the illumination system configured to generate an illumination pattern and to generate reflections of the illumination pattern off a cornea of a subject, wherein the illumination system is aligned along an axis of centers of the illumination pattern. The system also includes a mobile communications device, the mobile communications device comprising an image sensor, the image sensor to capture an image of the reflected illumination pattern; and a corneal topography optical housing coupled to the illumination system and coupled to the mobile communication device, wherein the corneal topography optical housing supports and aligns the illumination system with the image sensor of the mobile communication device. In some embodiments, the corneal topography optical housing comprising an imaging system coupled to the image sensor. In some embodiments, the imaging system further comprising a Keplerian configuration to magnify the image of the reflected illumination pattern being evaluated and also to decrease an optical path length between the cornea of the subject and the image sensor. In some embodiments, the imaging system comprises two or more mirrors, the two or more mirrors being positioned in an image path of the reflected illumination pattern image and located in front of a position of the image sensor of the mobile communication device. In some embodiments, a surface of the mobile communication device is tilted with respect to the vertical axis to provide enhanced viewing of the reflected illumination pattern image by the examiner. In some embodiments, the mobile communication device-based corneal topography system of claim1, the imaging system comprises two or more mirrors and the two or more mirrors are titled with respect to a vertical axis and/or a horizontal axis. In some embodiments, the illumination system is titled upward by an angle of inclination with respect to a horizontal axis to facilitate alignment with an eye of a subject being examined. In some embodiments, the illumination system, the corneal topography optical housing and the mobile communication device are positioned to maintain a horizontal plane of alignment between a subject and an examiner's during operation of the corneal topography system. In some embodiments, the corneal topography housing further comprising a first mirror and a second mirror, the first mirror and the second mirror being partial reflectance mirrors. In some embodiments, the system further comprises two or more proximity sensors, the two or more proximity sensors coupled to the illumination system and utilized to determine whether a left eye or a right eye of the subject is being examined.

INCORPORATION BY REFERENCE

All patents, applications, and publications referred to and identified herein are hereby incorporated by reference in their entirety, and shall be considered fully incorporated by reference even though referred to elsewhere in the application.

