APPARATUS FOR MONITORING A HUMAN OR ANIMAL SUBJECT'S BODILY
FUNCTION
TECHNICAL FIELD
This invention relates to apparatus for monitoring a human or animal subject's bodily function in vivo via the subject's eye.
BACKGROUND ART
Apparatus for carrying out such monitoring has previously been proposed. WO90/12534 describes such a device and a wide range of uses to which this can be put and the disclosure thereof is incorporated herein.
WO02/071932 discloses an improvement to this apparatus in which a pupillometer is used to assist in aligning the apparatus with the pupil of the eye and WO2006/079824 discloses a further improvement in which pulsed input light is used and the returning light recorded at a timing such that the majority of the light recorded is diffuse light, ie the eye is used as an integrating sphere whereby the signal to noise ratio is improved. The disclosure of both these documents is also incorporated herein.
The present invention relates to a particular manner of applying the above technology to facilitate its convenient use by the subject or another person.
SUMMARY OF INVENTION
According to a first aspect of the invention, there is provided apparatus for monitoring a human or animal subject's bodily function in vivo comprising a telecommunication device provided with an eyepiece for locating a subject's eye relative to a light source and light recording means, the apparatus being arranged to direct light into the subject's eye through the pupil of the eye and to record light returning through the pupil from the interior of the eye and to transmit data recorded to remote analysing means.
Preferably the remote analysing means is arranged to analyse the data transmitted thereto and to transmit back to the apparatus an indication of said analysis.
A preferred form of the invention comprises a mobile telephone with a built-in camera and flashlight and an eyepiece for locating the subject's eye relative to a camera lens of the telephone. The flash is used to direct light into the subject's eye and the camera is used to record the light returning from the retina. The image or data recorded is then transmitted by the telephone to remote analysing means, eg a spectrophotometer, and the result of this analysis is transmitted back to the mobile telephone to the subject. The image/data recorded may, in a preferred embodiment, be what is commonly referred to as Ved eye'.
The apparatus may have particular application for the monitoring of glucose levels in the blood (via the blood vessels of the retina) to enable a diabetic to determine what medication they require at that time.
Other preferred or optional features of the invention will be apparent from the following description.
BRIEF DESCRIPTION OF DRAWINGS
The invention will now be further described, merely by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a schematic diagram illustrating use of a preferred embodiment of the invention, and
Figure 2 is an enlarged cross-sectional view of a subject's eye located by an eyepiece of apparatus such as that illustrated in Figure 1. DESCRIPTION OF PREFERRED EMBODIMENT
Figure 1 shows a mobile telephone 1 with a built-in camera 2, comprising a lens 3, one or more flash lights 4, eg LEDs, and a CCD array 5 for recording the light received thereby. A transparent window 6 is provided in front of the lens 3 to protect this from damage. The mobile telephone is also provided with an eyepiece 7 in the form of a flexible cowl around the window 6 and LEDs 4. As shown, a subject can place his or her eye 8 in front of the camera 2 with the eyepiece 7 in contact with the subject's face around the periphery of the eye 8.
Figure 2 shows an enlarged view of an eye 8 located by an eyepiece 7 in front of a camera lens 3. The Figure shows the retina 10, lens 11, iris 12, pupil 13 and cornea 14 of the eye.
A bodily condition of the subject can be monitored by examination of the retina of the eye and, in particular, the blood vessels in the retina, eg by spectrophotometric analysis of light returning from the retina 10 as described in further detail in WO 90/12534. In the apparatus described herein, the light returning from the eye is sensed by a CCD or CMOS array 5. The data therefrom may then be stored in the telephone's memory and transmitted in a similar manner to the transmission of a photograph or other data by a known mobile telephone. The data is received by a transceiver 20 at a remote location. The transceiver comprises or is in communication with a spectrophotometer which carries out an analysis of the data received. The results of this analysis are then transmitted back to the mobile telephone 1 to inform the subject of the results. This may, for example, be by a voice message or a text message.
The eyepiece 7 serves to exclude ambient light from entering the eye and to locate the eye 8 in line with and at the appropriate distance from the lens 3. This distance should be carefully set and the eyepiece 7 may be adjusted to suit a particular subject prior to its first use and to ensure that this distance is the same each time the apparatus is used by that subject. In a preferred embodiment, the length of the eyepiece 7 and/or the position of the lens 3 may be adjustable to locate the eye at the desired distance from the lens 3. Another possibility would be to use an adjustable lens, eg a fluid filled lens the focal length of which can be altered by adjusting the pressure of the fluid therein.
The light source 4 may be similar to a conventional flashlight in a mobile telephone, eg an LED emitting white light. In alternative arrangements, more than one LED may be provided and each may emit a different wavelength depending on the substance to be monitored.
In some cases, an infra-red wavelength may be used. In some cases, it maybe desirable to focus the illumination light in the plane of the pupil 13 (so as to provide a Maxwellian view) in which case the illumination light may be provided via an optical fibre and/or a focussing lens as described in the prior art documents referred to above. In addition, alignment means may be provided to move the light source laterally with respect to the eye so it can be aligned accurately with the centre of the pupil and can following small movements of the eye.
The light returning from the eye that is recorded may be that which sometimes causes Ved eye' in a photograph of a person, this being light that is returning from the blood vessels in the retina.
In a preferred arrangement, a pulsed light source is used and the detection of light returning from the eye is arranged at a set timing so as to reduce the amount of light reflected from the cornea or the lens 11 that is detected thereby increasing the signal to noise ration for light returning from the interior of the eye. In addition, this has the advantage of ensuring the light returning from the eye is predominantly diffuse light, which also improves the measurements made by reducing the effect of variations in the illumination of the eye. Further details of this are provided in WO2006/079824 so will not be discussed further here. In preferred embodiments, a pupillometer may also be provided to assist in aligning the eye with the lens. This is described in WO02/071932 so will not be described further here.
As indicated above, in a preferred embodiment, the mobile telephone is a conventional camera phone with a suitable eyepiece fitted thereto. In another embodiment, a specifically modified mobile telephone may be provided. This has the advantage that the lighting means, the lens, the light detector and the software controlling these can be modified or adapted to assist in providing the functions described herein. A subject may, for example, be provided with a mobile phone which can be used as a telephone but which is also specifically adapted to provide the required functions, eg to sense glucose for someone with diabetes. A similar instrument may also be used, for example, in a doctor's surgery or on the ward in a hospital.
If the apparatus is to be used for more than one person, it preferably adjustable so that the length of the eyepiece and/or position of the lens 3 can be adjusted. Preferably, it can also record the identity of the subject, eg by way of iris or DNA recognition (as described in the above-mentioned prior art documents).
The apparatus described above thus provides, in its simplest form, a user- friendly device that can be used by a subject at home to monitor a bodily function as represented by the presence of a given substance in the blood. A particular example is the monitoring of glucose levels in the blood for a diabetic but many other uses are possible. More elaborate versions of the device may be provided for use by doctors or nurse or within a hospital.