EP2779888A1 - Rétinographe - Google Patents
RétinographeInfo
- Publication number
- EP2779888A1 EP2779888A1 EP12849317.8A EP12849317A EP2779888A1 EP 2779888 A1 EP2779888 A1 EP 2779888A1 EP 12849317 A EP12849317 A EP 12849317A EP 2779888 A1 EP2779888 A1 EP 2779888A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- focus index
- light
- light source
- leds
- fundus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
- A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
- A61B3/12—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for looking at the eye fundus, e.g. ophthalmoscopes
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
- A61B3/0008—Apparatus for testing the eyes; Instruments for examining the eyes provided with illuminating means
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
- A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
- A61B3/14—Arrangements specially adapted for eye photography
- A61B3/15—Arrangements specially adapted for eye photography with means for aligning, spacing or blocking spurious reflection ; with means for relaxing
Definitions
- Embodiments of the invention relate generally to an ophthalmic photographing apparatus.
- a focus index such as a split-bar pattern
- a focus index projection system using a light source with wavelength in the range of dark red or near infrared.
- the focus index projection is then branched into a fundus illumination path through a beam splitter or a flipping mirror (shutter).
- Another way of branching the focus index projection into the fundus illumination path is through the projection of the focus index on to a retractable stick mirror which is conjugate to the fundus of a subject's eye (Ef).
- the split-bar pattern is then re-imaged at the fundus (Ef) of the eye under examination after the illumination beam passes through the ocular lens and the eye.
- NIR Near Infra Red
- the operator judges the degree of focus by looking at the alignment of the two halves of the split bar image.
- the focus setting is correct, the two halves of the split bar image become aligned; otherwise, the two halves are misaligned, depending on the direction and amount of defocus.
- a control system of the fundus camera turns off the NIR light sources for both the fundus and the focus index illumination and retracts the stick mirror out of the main illumination path before turning on the flash light (white) to capture a color fundus image.
- the entire focus index projection unit including the light source, mask, condenser lens, bi-prism, slit, folding mirror, projection lens, and the solenoid retractable stick mirror, are moved along the optical axis to synchronize the movement of the focusing lens, which is usually located after an imaging aperture stop, through a mechanical linkage, such as a gear system.
- This conventional approach requires a large space to accommodate the movement of the entire focus index projection unit, the focusing lens in the imaging path, and the mechanical linkage, and, therefore, is not suitable for a low-cost compact system design.
- the focus index illuminating light source green Light Emitting Diode (LED)
- the focus index optical assembly Since the arm and the focus index together need to be flipped in and out at a rapid rate during each switching between the observation mode and the image capturing mode, the light source would inevitably experience shock and vibration, and this method would result in reliability issues.
- the visible light such as the green LED disclosed, is not suitable for non-mydriatic application as the patient's pupil size can be sensitive to the visible light generated by the green LED.
- an ophthalmic imaging apparatus for capturing images of an eye according to some embodiments includes a fundus illumination system, the fundus illumination system includes a spatially interlaced light source array of one or more wavelength bands and a focus index illumination light source where the focus index illumination light source is mounted on a non-moving part of the ophthalmic imaging apparatus, a focus index optical assembly, and a fundus imaging system.
- FIG. 1 is a cross sectional view of a compact fundus camera in accordance with some embodiments of the present invention.
- FIGs. 2a and 2b show an exemplary crystalline lens diaphragm with small prism mirror attached at a central light blocking disk.
- FIGs. 2c and 2d show another exemplary crystalline lens diaphragm with small prism mirror attached at a central light blocking disk.
- FIGs. 3a, 3b, 3c, 3d, 3e, and 3f show an example of an interlaced white and NIR ring LED arrays.
- FIGs. 4a and 4b show an example of a focus index optical assembly with multiple fixation targets.
- FIG. 5 shows the lens slider mounted with different compensation lenses according to some embodiments of the present invention.
- FIG.l shows a cross sectional view of a compact fundus camera in accordance with some embodiments of the present invention.
- some embodiments of the fundus camera include an ocular lens 1; hole mirror 2; aperture stop 3; relay lens system 4; a sensor 5; a relay lens 6; a mirror 7; a solenoid 8; an optical assembly 9 with housing structure 9a, bi-prism 9b, focus index 9c, and fixation targets 9d; a focus index illuminating light source 10; a field stop 10a; a relay lens 11 ; a small folding mirror 12; a second relay lens 13; a crystalline lens diaphragm 14; relay lens 15; a ring aperture plate 16; an aperture 17; a condenser lens 18; LED ring arrays 19a and 19b; a diffuser plate 20; black dot plate 21; a lens slider 22; and filters 23.
- light from light source 10 can be directed by folding mirror 12 through second relay lens 13, optical assembly 9, black dot plate 21, mirror 7, lens 6, aperture 17, hole mirror 2, and ocular lens 1 to the eye.
- light from LED ring arrays 19a and 19b can be directed through lenses 18, 15, 13, 6, and 1 to the eye.
- Light from the eye can be directed through lens slider 22 and lens 4 onto sensor 5.
- lenses 1, 4, 6, 13, 15, and 18 shown in the FIG. l are all illustrated as a single-element lens, some or all of them can be multi-element lenses. This system is further described below.
- the focus index illuminating light source 10 which can be a NIR LED, is mounted on a fixed part.
- Such fixed part for example, can be a lens housing mounted on a base structure of the apparatus.
- this fixed part is kept further away from the movable focus index optical assembly 9 to minimize the vibration or shock energy by-product generated from the rapid in-and-out retraction motion of the focus index optical assembly 9 during each switching cycle between an observation mode and an image acquisition mode.
- the reliability of the focus index illumination can be improved by reducing the vibration and shock by-product.
- Such embodiments have a further advantage of removing the focus index illuminating light source 10 from the focus index optical assembly 9 so that additional space becomes available between the relay lens 13 and the black dot plate 21 for wider range of focus adjustment.
- a black dot plate 21 is commonly used in a fundus camera setup to eliminate surface reflection of the ocular lens 1.
- a field stop 10a is attached in front of the light source 10, such as a NIR LED, as shown in FIG. 1, so that it is re-imaged by the relay lens 11 to a position near the front focal plane of the second relay lens 13 of the fundus illumination path.
- the second relay lens 13 re-images the crystalline lens diaphragm 14 to a surface close to the back surface of the crystalline lens (Eel) of the eye (E), with relay lens 6, and ocular lens 1.
- the relay lens 13 also serves as the collimating lens for the focus index illuminating light beam generated from the light source 10.
- a small folding mirror 12 such as a prism mirror, can be attached onto and hidden from ring arrays 19a and 19b behind the central disk 28 of the crystalline lens diaphragm 14 to minimize interference with the fundus illumination beam when passing through the ring opening of the diaphragm 14.
- the construction of the prism mirror on the crystalline lens diaphragm 14 is described in details below and is shown in embodiments of diaphragm 14 shown in FIGs. 2a, 2b, 2c, and 2d.
- the optical axis of the focus index illuminating beam coincides with that of the lens 13 and the focus index 9c.
- the size of the folding mirror 12 and the position of the combination of the light source 10 and the field stop 10a can be adjusted to minimize stray light from the focus index illumination beam by minimizing the beam size illuminating the central part 44 of the focus index optical assembly 9.
- FIGs. 2a, 2b, 2c, and 2d show examples of crystalline lens diaphragms 14 in accordance to some embodiments of the present invention.
- FIGs. 2a and 2b illustrate a diaphragm constructed from material that is capable of light blocking/absorption.
- diagram 14 is formed of a central disk 28 with supporting structures 30.
- FIG. 2b illustrates a cross section along the A-A direction illustrated in FIG. 2a.
- FIGs. 2c and 2d show another example diaphragm 14 constructed by depositing a thin layer of light blocking material 30 onto a translucent material 29.
- FIG. 2d illustrates a cross section along the A-A direction illustrated in FIG. 2c.
- illumination can be achieved by turning on the NIR LED ring array 19b of a dual band interlaced LED ring arrays 19a and 19b and the focus index illuminating light source 10.
- the spatially interlaced dual-band LED ring array can be arranged on a single Printed Circuit board (PCB) or separated into multiple layers with supporting structure holding the two interlaced LED ring arrays 19a and 19b together.
- FIGs. 3e and 3f show a ring array which constitutes of two layers of multiple LEDs.
- LED ring array 19a includes LEDs 39 mounted on printed circuit board 32.
- LED ring array 19b includes LEDs 38 mounted on printed circuit board 34.
- LEDs 38 are arranged to insert through holes 36 on printed circuit board 32. As shown in FIG 3e, then, a ring of LEDs 39 and LEDs 38 are formed.
- the LEDs 39 can also be arranged in a ring array, evenly spaced apart, and interlaced spatially with LEDs 38 so that each NIR LED can illuminate the condenser lens 18 through the open holes between adjacent white LEDs of the first layer.
- the order of the LED layers and the combination of the visible band and the NIR band can be alternatively arranged within the spirit of the subject invention.
- FIGs. 3a and 3b illustrate LED ring 19a. As shown in FIG. 3a, LEDs 39 are arranged in a ring on a printed circuit board 32. Openings 36 in printed circuit board 32 are interspersed between LEDs 39. FIG. 3b illustrates a cross section along the A-A direction of LED ring 19a.
- FIG. 3e An example composite of these 2 layers is shown in FIG. 3e.
- One of the advantages of this approach is the elimination of the need of a dichroic filter to combine the light beams of the different wavelength bands from each of the two separated LED ring arrays 19a and 19b.
- the NIR light generated from the array 19b is focused on the ring aperture plate 16 through the opening 36 of a mount, such as the PCB of the white LED arrays 19a as shown in FIG. 3a, a condenser lens 18 and a diffuser plate 20 which makes the illumination more uniform across the fundus (Ef) image plane.
- the ring aperture plate 16 is conjugate with a position between the pupil (Ep) and the cornea of the eye through the relay lenses 15, 13, and 6, the hole mirror 2, and the ocular lens 1.
- the crystalline lens diaphragm 14 is conjugate with the back surface of the crystalline lens (Eel) through relay lenses 13 and 6, and the ocular lens 1.
- the cornea ring aperture 17 is conjugate with the cornea.
- FIGs. 4a and 4b shows an exemplary drawing of a portion of optical assembly 9.
- FIG. 4a provides a planar view
- FIG. 4b provides a cross-sectional view of optical assembly 9.
- optical assembly 9 includes a covering of thin light- blocking material 44 on a translucent plate 42 to form focus index 9c and fixation targets 9d.
- Focus index 9c can be a slit opening surrounded by a light-blocking central disk.
- Multiple fixation targets 9d can be black dots or small openings of any useful shape and size. These fixation targets can be used to stabilize the eye during examination by drawing the patient's attention to any one of these fixation target(s).
- this method provides passive fixation in a sense that the target illumination is shared with the fundus illumination light source and does not need any additional fixation light source for each fixation position as in the case of the conventional fundus cameras and further save the cost and power of the system.
- the longitudinal position of these fixation targets 9d relative to that of the focus index 9c can be adjusted to compensate for the field curvature and the index of refraction of the bi-prism 9b so that images of both the fixation targets and the focus index are at focus together at the fundus (Ef).
- the bi-prism 9b is attached on top of the focus index 9c to deflect the incident beam into two opposite directions.
- FIG. 4a is a top view of the exemplary optical assembly 9 with the patterns for the focus index and the fixation targets.
- FIG. 4b shows the side view of the translucent plate of FIG. 4a showing the bi-prism 9b attached at the top of the focus index 9c.
- the focus index optics assembly 9 can be held in position by a mechanical housing structure 9a (FIG. 1) fastened on the shaft of the solenoid 8 so that the focus index optics assembly 9 can be flipped in-and-out of the fundus illumination path when the operator switches between the observation mode and the image capturing mode.
- the combination of the focus index optical assembly 9 and the solenoid 8 mounted on a translation stage can be moved longitudinally together with the movement of the sensor 5.
- the movement can be at different rates facilitated by a CAM wheels structure, a gear system or other commonly used methods to control mechanical movement.
- the split-bar pattern is superimposed onto the fundus image captured by the sensor 5 through the ocular lens 1, the central opening of the hole mirror 2, the aperture stop 3, the lens slider 22, and the relay lens system 4.
- the split-bar pattern can then be displayed on a display device so that the operator can observe and adjust for focusing.
- the sensor 5 in some embodiments is a dual-band sensor which can capture both color and NIR images.
- An example of this type of sensor can be constructed by removing the IR cut filter of a typical solid-state sensor, such as a color CMOS or a CCD sensor; where the silicon material is sensitive to visible wavelength band and NIR wavelength band up to around 1,000 nm.
- This approach has the advantage of using only one sensor for both the observation mode (using NIR light) and the image capturing mode (using visible light).
- Removing the IR cut filter has the advantage of allowing the sensor to capture the dark red spectrum of the white LED illumination which penetrates deeper into the choroid area of the eye; on the other hand, it can blur the color image slightly due to chromatic aberration.
- a lens selection module such as the lens slider 22, can be used to achieve adequate focus range for different eye conditions during image acquisition.
- slider 22 may be a light blocking material 42 with multiple transparent areas.
- slider 22 includes a first position 44, a second position 45, a third position 46, and a fourth position 47.
- slider can be positioned to allow light to pass through one of positions 44, 45, 46, and 47 to arrive at sensor 5.
- FIG. 5a is a planar view of slider 22 while FIG. 5b is a cross sectional view along A- A.
- Slider 22 can be utilized for fundus imaging of patients with a wide range of refractive error.
- the operator can move lens slider 22 to first position 44, which can be an open hole, as shown in FIGs. 5a and 5b.
- first position 44 can be an open hole, as shown in FIGs. 5a and 5b.
- the lens slider can be moved to a second position 45 for diopter compensation with a weak negative lens.
- the slider can be moved to third position 46 with a weak positive lens during image acquisition.
- the fourth position 47, with a strong positive lens, in the exemplary lens slider 22 can be used for imaging the anterior area of the eye.
- the operator can image the anterior area of the eye using the system in FIG.
- the number of compensation lenses and the ordering positions of the exemplary slider 22 can vary based on the clinical needs and can be understood by a person of ordinary skill in the art.
- an operator will first align the system to a patient's eye under examination by positioning the system so that lens 1 is about 2" to 5" away from the cornea of the eye and adjust the system laterally (X-Y) so the image of the pupil of the patient's eye is centered in the NIR video image on the display device (not shown) that displays the image captured by sensor 5 during the observation mode.
- both the focus index illuminating light source (NIR) 10 and the LED ring array (NIR) 19b are turned on to illuminate the focus index and the fundus during the observation mode.
- the operator can move the system toward the patient's eye until the image of a working distance indicator (not shown), e.g.
- the imaging mode can be triggered to acquire the fundus image.
- the imaging mode can be triggered by a commonly used user's input, such as a button press on a joystick control, a mouse click, a foot rest.
- the focus index optics assembly 9 will flip away quickly from the light path as described above.
- the focus index illuminating light source 10 and the LED ring array (NIR) 19b will also be turned off and the white LED arrays 19a will then flash the fundus for capturing a fundus image by the image sensor 5.
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- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Medical Informatics (AREA)
- Biophysics (AREA)
- Ophthalmology & Optometry (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Physics & Mathematics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Eye Examination Apparatus (AREA)
Abstract
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201161561266P | 2011-11-18 | 2011-11-18 | |
PCT/US2012/065371 WO2013074851A1 (fr) | 2011-11-18 | 2012-11-15 | Rétinographe |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2779888A1 true EP2779888A1 (fr) | 2014-09-24 |
EP2779888A4 EP2779888A4 (fr) | 2015-07-15 |
Family
ID=51356359
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP12849317.8A Withdrawn EP2779888A4 (fr) | 2011-11-18 | 2012-11-15 | Rétinographe |
Country Status (1)
Country | Link |
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EP (1) | EP2779888A4 (fr) |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005013474A (ja) * | 2003-06-26 | 2005-01-20 | Canon Inc | 眼底測定装置及び眼底血流計 |
US7347553B2 (en) * | 2004-09-24 | 2008-03-25 | Canon Kabushiki Kaisha | Ophthalmic image sensing apparatus |
JP4744973B2 (ja) * | 2005-08-05 | 2011-08-10 | 株式会社トプコン | 眼底カメラ |
JP5031405B2 (ja) * | 2007-03-02 | 2012-09-19 | キヤノン株式会社 | 眼科撮影装置、眼科撮影装置の制御方法およびプログラム |
-
2012
- 2012-11-15 EP EP12849317.8A patent/EP2779888A4/fr not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
EP2779888A4 (fr) | 2015-07-15 |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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RA4 | Supplementary search report drawn up and despatched (corrected) |
Effective date: 20150617 |
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RIC1 | Information provided on ipc code assigned before grant |
Ipc: A61B 3/15 20060101ALI20150611BHEP Ipc: A61B 3/12 20060101AFI20150611BHEP |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 20160114 |