Invented by Robert J. Wood, Raymond A. Lia, Jon R. Salvati, Robert L. Vivenzio, Ian K. Edwards, Ervin Goldfain, Colin J. Wolff, Welch Allyn Inc
The Welch Allyn Inc invention works as followsA skin measuring microscope consists of a housing, a device that measures the skin along an imaging axis and an illumination system. The illumination system comprises a plurality LEDs arranged in a ring configuration at the distal end.
Background for Digital-based medical devices
There are many types of medical equipment that can be used to conduct patient examinations. The devices include an otoscope to examine the ear; an ophthalmoscope to examine the eye; a laryngoscope to inspect the throat; a skin-measuring microscope for the examination of skin conditions and defects, and a cervix-examining colposcope. These devices are available in hand-held versions, including those sold by Welch Allyn, Inc., of Skaneateles Falls, N.Y. The optical versions of such devices as an otoscope and an ophthalmoscope have a diagnostic handle that contains a set standard or rechargeable battery. An instrument head attached to the handle has the optics necessary to examine a target. At least some of these instruments have been produced in digital versions.
Still, certain examinations such as those that involve the eye have only been possible with a dedicated, much more complex apparatus such as a Fundus camera, which is used to conduct retinal imaging and to detect other maladies such as diabetic macular degeneration and macular retinopathy, given the required field of vision and the fact that a patient can be examined without the need to administer eyedrops to dilate the pupils for the purposes of an examination.
It is an ongoing and general need to improve digitally-based medical devices including medical examination tools.
The illumination system includes a first light source emitting the illuminating beam in a narrow wavelength range between about 550 nm and 600 nm, a second light source for emitting a flash of white (broadband) light, wherein said illumination system directs both the illuminating beam and the flash of the white light towards the target. The illumination system comprises a first source of illuminating (broadband white) light emitting in a narrow range between about 550nm and 600nm. It also includes at least one lens that directs light rays from the illuminating and flashing white light to the target. The ophthalmic device further includes an imaging system that directs the illuminating rays reflected by the target to a viewing position. This imaging system comprises: a camera at the viewing point for detecting the image and capturing it, and a display connected electrically to the camera for displaying this image. The ophthalmic device also includes a memory to store the captured digital images of the target. A processor is electrically connected with the memory, illumination system and imaging system in order to control their operation.
According to one version, a hand-held ophthalmic device comprises a lens that converges light rays from the illuminating and flashing white light towards an apex. The apex of one embodiment is located at or near the pupil of an eye.
Accordingly, in another version, an imaging system includes a plurality lenses forward of the viewing position and centered on the optical axis, wherein one lens includes an optical focus element that can vary its thickness when a focusing current is applied. The optical focusing element may be a liquid lens, and the instrument may include a focus control that can automatically adjust the voltage to capture a focused image. One or more of these lenses can also provide a system that is less susceptible to image jitter.
According to one version of the instrument, it includes a memory that stores at least 2 preset focusing values. The processor controls the application of these voltages to the focusing elements, which in turn alternates the focal lengths of the focusing elements, so that the digital display displays the captured target at two different focal lengths. In a further version, an imaging system includes a beam-splitter that directs a portion of illuminating reflected light from the target to a secondary viewing location. A second digital camera is located at the second viewing position for capturing and detecting a digital image of the object of interest. A second plurality lenses is located forward of the 2nd viewing location. One of these lenses has a second focus element that can change its thickness when a second voltage is applied to it. The digital display is also electrically connected to this second digital imager to display the second image on the digital display.
The instrument comprises, preferably, a DC source to provide electric power to both the illumination system as well as the imaging system. In one version, a DC power source is included in the power source. This could be a battery or a rechargeable DC source. In another version, a rechargeable DC power supply includes either a super- or ultra capacitor.
The first light source may be an LED, laser diode or incandescent lamp. In one version, a first light source includes means to vary the wavelength of the light emitted from the first source.
According to one version of the second light source, it can include a plurality LEDs that are each individually illuminable. Each LED emits light with a different wavelength from another LED. The second light source may also include at least one white LED, white laser diode or white incandescent light bulb.
In a second version, each fixation source is positioned at a selected distance from the optical system. The fixation sources are arranged in a circular formation and illuminated individually so that, when a person views a fixed light source directly, an area of their retina can be seen by the imaging system. In another version, multiple fixation lights are positioned each at a selected distance from the optical system. The fixation lights are arranged in circular pattern and illuminated individually so that, when a person views an illuminated light source, a preselected part of their retina is visible.
The processor in the instrument described herein can contain a program that stitches together, into a single continuous digital image captured by the imaging device, pre-selected areas of a person’s retina.
The digital display of at least one version comprises a cursor box that can be sized and positioned by the processor according to the user’s input. This allows the user to select an area on the digital display which corresponds to the area of a target of interest, to be captured in a digital still picture.
The processor can be programmed to capture a digital image in response to a voice command.
Accordingly, in another version of the instrument, it comprises means to control a property emitted by either the first or second light source. These means can include an aperture wheel or adjustable iris to control a width for a beam of lighting emitted from the first or second light source. In another embodiment, the width-controlling means can include at least one light filter placed in front of the first light source or second light source to filter the light emitted from the first light source or second light source. The at least filter can be, for example a color filter, or a filter that polarizes light.
In at lease one version, an instrument is provided with a communication interface to connect the processor to a processing system external and exchange data between the processor system and the external system. On the instrument, or in another way, an indicator can indicate that a data transfer is taking place and the status. Data exchanged between the processor, the external system and the instrument can include both software upgrades sent to the instrument and digital images captured by the instrument. A wired or wireless communication interface is at least one option for the communication interface. A wired interface can include at least one USB interface, a ePCI, a PCI, or an Ethernet interface. Wireless communication interfaces can include an IEEE 802.11, cellular, or other wireless standard-compliant interface.
According to a third version, an ophthalmic device further includes a patient interface, which includes an eye cup, for coupling the instrument with the patient and is configured to contact a region of their face around an eye. According to at least one embodiment, the eye cup is made of a flexible material that conforms to the area of the face of the patients surrounding the eye. It also includes flexible ribs to conform flexibly to the area of the face of the patients surrounding the pupil. In one preferred version, an opening is provided through which a patient’s pupil can be seen from outside the examination device. The distance between the pupil and the converging lenses, and the width and length of the light beam emitted from the first or second light sources are adjusted using the above so that the retinal region illuminated by illuminating lights is between approximately twenty degrees and thirty five degrees.
According yet another version, it is provided a method for performing an ophthalmic exam, the method including the steps of: Illuminating a targeted of interest with amber light having a narrow range of wavelengths between about 550nm and 600nm, and after said step, Illuminating the Target of Interest using white (broadband), and simultaneously with said step, Illuminating the Target of Interest using white light, Capturing a digital still picture of the target.
According to at least a embodiment, the step illuminating a target of interest with white light includes the additional step emitted the white light for fewer than one-tenth second.
In one version of the method, the step to simultaneously capture the digital still image includes the use of an electronic digital camera and the display image is illuminated with the amber lamp. In one version of the method, it also includes the step of automatically focusing and illuminating a target of interest with the amber lighting. In one version of the method, the second step includes the addition of adjusting the focal range of the liquid lens. This can be done by varying the voltage applied to the lens.
In one preferred version of the invention, the object of interest is an “eye” and the method of illuminating it using amber lights includes the additional step that light rays from the amber lighting are converged at a point near or at the pupil of the eye. In one embodiment, an LED emitting amber light is used to perform the illumination step. The LED can also be a white one with an amber filter placed in front.
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