Method and system for recognizing and tracking features in fundus images

Abstract

The present invention provides a system and method for allowing individuals with retinal disease to monitor fundus images at home, the system being applicable to handheld mobile devices. [Solution] A first reference coordinate of the fundus of the individual is tracked and aimed by an optic disc cupping retinal vascular target, and a second reference coordinate of the fundus of the individual is tracked and aimed in cooperation with a foveal target, the first reference coordinate being selected from the optic disc, a retinal vein branch or a retinal artery branch of the fundus of the individual, the second reference coordinate being the fovea of ​​the fundus of the individual, and a fundus image is acquired, the fundus image being obtained when the tracking and aiming of the first reference coordinate and the second reference coordinate by the composite aiming point is successful.

Description

[Technical field]

[0001] The present invention relates to a method and system for recognizing and tracking features in fundus images, in particular to a method and system for recognizing and tracking features in time-lapse fundus images of an individual, and more particularly to a portable / home use method and system for recognizing and tracking features in time-lapse fundus images of patients with retinal pathology. [Background technology]

[0002] In addition to high myopia, causes of retinal lesions include triple risk (high blood pressure, high blood sugar, high blood lipids) and diabetes, and there are also groups with macular degeneration as a genetic disease. The capillaries of the retina are prone to lesions, which impair visual function due to retinal hemorrhage, edema, or necrosis. In the case of diabetic retinopathy in diabetic patients, there may be no symptoms at the early stage. In general, fundus lesions begin to appear in 30% of patients who have had diabetes for more than 10 years, and the incidence rate reaches 80% in patients with a history of the disease of more than 25 years. Diabetic retinopathy develops mainly when a long-term hyperglycemic environment damages the vascular endothelium of the retina, causing a series of fundus lesions, as diabetes is a systemic disease. Diabetic retinopathy may not show any symptoms at the early stage. However, poor blood sugar control, insulin-dependent diabetes, high blood sugar, and renal lesions may all accelerate the onset of diabetic retinopathy and further accelerate the development of fundus lesions. It is currently known that almost all type 1 diabetes patients develop retinal lesions after 15 to 20 years, with 20 to 30% of these patients going on to become blind. In addition, more than 60% of type 2 diabetes patients have retinal lesions, which is the leading cause of blindness in the 20 to 65 year old population.

[0003] For example, in the conventional diagnosis of retinal lesions, such as diabetic retinopathy, fundus examination is essential to observe changes in the retina at the fundus. In general, in conventional fundus examination, the pupil must first be dilated using mydriatic drugs, and then the presence or absence of vascular proliferation or other lesions in the fundus must be examined using an ophthalmoscope and a slit lamp. However, this has the disadvantages of taking some time, being relatively difficult to record the examination results, and not being able to objectively compare the conditions before and after treatment. Therefore, patients generally find it difficult to accept these, and as a result, the examination rate is declining.

[0004] In view of the above, how to develop a device that allows medical personnel to examine or diagnose patients with retinal lesions, or that can be easily operated by patients with retinal lesions in a home environment and does not cause discomfort during the operation process, allows easy examination by regularly recognizing and tracking the characteristics of fundus images, has standardized retinal images with high-definition image quality, improves retinal image quality, is easy to create image files, and can be considered as changes in images at different points in time after a certain period of time has passed, thereby solving the shortcomings of the prior art and ensuring the accuracy of diagnosis is currently a pressing issue for those skilled in the art. Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, the object of the present invention is to provide a device that can be operated more easily by medical professionals or other people in cooperation with each other than with the conventional technology, or that can be easily operated by an individual on his or her own, that allows the user to easily recognize, track and inspect the characteristics of fundus images of both eyes at intervals of a certain period of time, and that is convenient for easily creating standardized high-definition fundus images and effectively comparing them, thereby improving convenience for the user and further improving the problems of the conventional technology.

[0006] Another object of the present invention is to provide a method for early warning and monitoring of microbleeds, hard exudates, petechiae, neovascularization, cotton wool spots, etc. in an individual's fundus, thereby effectively solving the problems of the prior art. [Means for solving the problem]

[0007] The method for recognizing and tracking features of a fundus image in the present invention includes the following steps: moving an image capture unit provided with a composite aim point to a first test position. The first test position allows the fundus of the individual to be located in the focal length section of the image capture unit. The composite aim point further includes an optic disc cup retinal vascular target and a fovea target. The optic disc cup retinal vascular target tracks and aims at a first reference coordinate of the fundus of the individual, and the fovea target tracks and aims at a second reference coordinate of the fundus of the individual in cooperation with the fovea target. The first reference coordinate is selected from the optic disc, branch retinal vein / retinal vein, or branch retinal artery / retinal artery of the fundus of the individual, and the second reference coordinate is the fovea of ​​the fundus of the individual. Next, a fundus image is acquired. The fundus image is obtained when the first reference coordinate and the second reference coordinate are successfully tracked and aimed by the composite aim point.

[0008] In one embodiment of the present invention, the optic disc further comprises an optic cup.

[0009] In one embodiment of the invention, the retinal vein branch is selected from the superior lateral vein (venula temporalis retinae superior), the superior medial vein (venula nasalis retinae superior), the inferior medial vein (venula nasalis retinae inferior) and the retinal artery branch is selected from the superior lateral artery (arteriola temporalis retinae superior), the superior medial artery (arteriola nasalis retinae superior), the inferior medial artery (arteriola nasalis retinae inferior) and the inferior lateral artery (arteriola temporalis retinae inferior).

[0010] In one embodiment of the present invention, the optic disc cup retinal vascular target and the foveal target are ring-shaped, cross-ring-shaped, ellipse-shaped, triangular, inverted triangle, square, diamond-shaped, trapezoidal, inverted trapezoidal, hexagonal, octagonal, or X-shaped.

[0011] In one embodiment of the present invention, the optic disc cup retinal vessel target further includes a circular target sight and a forward and reverse fork sight arranged radially from the circular target sight in a generally X-shape.

[0012] In one embodiment of the present invention, the circular target sight is capable of tracking and aiming at the optic disc cup.

[0013] In one embodiment of the present invention, the forward and reverse fork sight further includes four branches for tracking and targeting the superior lateral vein or artery, the superior medial vein or artery, the inferior medial vein or artery, and the inferior lateral vein or artery, respectively.

[0014] In one embodiment of the present invention, if the tracking and aiming of the first and second reference coordinates by the composite aim point fails, an error message is sent. Then, the focal length to the fundus is evaluated by calculating a difference value with the fundus image, and the image acquisition unit is moved to a second test position. The second test position is an appropriate focal plane position. And, the following steps are repeated: the image acquisition unit provided with the composite aim point is moved to a first test position. The first test position allows the fundus of the individual to be located in the focal length section of the image acquisition unit. The composite aim point is further provided with an optic disc cupping retinal vascular target and a foveal target. The optic disc cupping retinal vascular target is used to track and aim the first reference coordinate of the fundus of the individual, and the foveal target is used to track and aim the second reference coordinate of the fundus of the individual in cooperation with the foveal target. In this way, another fundus image is acquired.

[0015] In one embodiment of the invention, fundus images acquired at different time periods are compared, in particular images of the optic disc, retinal vein or artery branches and fovea of ​​the fundus of an individual.

[0016] In one embodiment of the present invention, when acquiring the fundus image, an aiming beam is first aimed at the individual's eye to assist positioning and aiming, thereby making it possible to standardize the orientation of the individual's eyeball.

[0017] In one embodiment of the present invention, a fundus boundary is defined based on the contrast ratio of the fundus image, and a fundus section obtained from the fundus image by the composite aim point is selected as a circle.Then, a feature identification and comparison unit calculates whether the fundus section and the fundus image previously created by the composite aim point meet a reference value of overlapping area, which is at least 72%.

[0018] The fundus image feature recognition and tracking system of the present invention includes an image acquisition unit. The image acquisition unit is provided with a composite aim point. The composite aim point is further provided with an optic disc cupping retinal vascular target and a foveal target. The image acquisition unit moves to a first test position. The first test position allows the fundus of the individual to be located in the focal length section of the image acquisition unit. The optic disc cupping retinal vascular target tracks and aims at a first reference coordinate of the fundus of the individual, and the foveal target tracks and aims at a second reference coordinate of the fundus of the individual in cooperation with the foveal target. The first reference coordinate is selected from the optic disc, the retinal vein branch or the retinal artery branch of the fundus of the individual, and the second reference coordinate is the fovea of ​​the fundus of the individual. The fundus image is acquired when the composite aim point successfully tracks and aims at the first reference coordinate and the second reference coordinate.

[0019] In one embodiment of the present invention, the optic disc cup retinal vascular target further includes a circular target aiming device and a forward and reverse fork aiming device. The forward and reverse fork aiming devices are arranged radially from the circular target aiming device in a substantially X-shape. The circular target aiming device tracks and aims at the optic disc cup. The forward and reverse fork aiming device further includes four branches. These branches track and aim at the superior lateral vein or superior lateral artery, the superior medial vein or superior medial artery, the inferior medial vein or inferior medial artery, and the inferior lateral vein or inferior lateral artery, respectively.

[0020] In one embodiment of the present invention, the apparatus further includes a feature identification and comparison unit, which is used to identify and compare the optic disc, the retinal vein branch or the retinal artery branch and the fovea in the fundus images acquired at different time periods.

[0021] In one embodiment of the present invention, the system further includes a fundus image database for storing fundus images acquired at different time periods.

[0022] In one embodiment of the present invention, the device further includes a display unit electrically connected to the image acquisition unit and the fundus image database, to which the fundus image is transmitted and displayed from the image acquisition unit, or to which the fundus image is transmitted and displayed from the fundus image database.

[0023] In order to make the above features and advantages of the present invention clearer and more concise, the present invention will be described in detail below with reference to the accompanying drawings. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram of an operation according to the method of the present invention. [Diagram 2] FIG. 2 is a schematic diagram of the operation of another method of the present invention. [Diagram 3] FIG. 3 is a schematic diagram of the operations in a further method of the invention. [Figure 4] FIG. 4 is a schematic diagram of the operations in the tracking and targeting method of the present invention. [Diagram 5] FIG. 5 is a schematic diagram of an operation process in another tracking and aiming method of the present invention. [Figure 6] FIG. 6 is a schematic diagram showing a case where the optic disc cup retinal blood vessel target and the foveal target in the present invention work together to track and aim at the first and second reference coordinates on the fundus, and targeting is successful. [Figure 7] FIG. 7 is a schematic diagram of a case where the first and second reference coordinates are tracked and aimed at, and targeting fails, in another embodiment of the present invention. [Figure 8] FIG. 8 is a schematic block diagram of a system according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The technical contents of the present invention are described below by means of specific specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed herein. However, the present invention may be implemented or applied in a number of different forms without departing from the spirit of the present invention.

[0026] The "one embodiment" of the present invention described in the specification is used to explain and indicate that a particular function, structure, or feature is included in the present invention. The term "one embodiment" found in the specification does not necessarily refer to all the same embodiment, nor is it an individual or alternative embodiment that excludes other embodiments. That is, some embodiments may describe some specific features that are not described in other embodiments. In addition, structures, components, or connections that are well known in the relevant field are not described in particular detail to avoid obscuring the novel and unique features of the present invention.

[0027] In one embodiment of the present invention, the term "individual" as used herein means a user or operator, such as a patient with retinal disease, particularly a patient with diabetic retinopathy. In another embodiment, the present invention may be operated by a medical professional, by another person in a home environment with the cooperation of a patient with retinal disease, or by a patient with retinal disease himself / herself in a home environment. In addition, an individual may recognize and track the features of a fundus image of one of both eyes, acquire and check the fundus image, and then switch to the other eye to acquire and check the fundus image.

[0028] 1 to 8, in one embodiment of the method for recognizing and tracking features of a fundus image of the present invention, the image acquisition unit 1 is moved to an examination position to acquire an image of the fundus of the individual. The examination position is located in front of the eye of the individual. At the same time, an aiming beam 51 emitted from a light source 5 may be first aimed at the individual to assist positioning and aiming. The light source 5 may be installed in a handheld mobile device 101. In other words, the eye E of the individual may look directly at a target light emitted from an image acquisition unit 1 (e.g., a lens) of a handheld mobile device 101 (i.e., a portable smart device or a mobile phone) of the present invention. In this way, the direction of the eyeball of the individual is standardized by reliably ensuring that the eye of the individual can look directly at the target light. At the same time, an image of the eye of the individual and an image of the target light may be transmitted to a display unit 3. In other words, the target light can standardize the direction of the eyeball of the individual in the display unit 3.

[0029] The present invention further provides a method for recognizing and tracking features of a fundus image. The steps of the method include: moving the image acquisition unit 1 provided with a composite aim point to a first test position. The first test position allows the fundus of the individual to be located in the focal length section of the image acquisition unit 1. The composite aim point further includes an optic disc cup retinal vascular target T1a and a fovea target T2a. The optic disc cup retinal vascular target T1a tracks and aims a first reference coordinate R1 of the fundus of the individual, and the fovea target T2a tracks and aims a second reference coordinate R2 of the fundus of the individual in cooperation with the fovea target T2a. The first reference coordinate R1 is selected from the optic disc, retinal vein branch or retinal artery branch of the fundus of the individual, and the second reference coordinate R2 is the fovea. The optic disc, retinal vein branch or retinal artery branch and the fovea can be regarded as three coplanar points on the fundus. In addition, the tracking and aiming can be performed by automatic tracking and aiming, semi-automatic tracking and aiming, or manual tracking and aiming. The optic disc further includes an optic disc cup. The retinal vein branch is selected from a superior lateral vein, a superior medial vein, an inferior medial vein, and an inferior lateral vein, and the retinal artery branch is selected from a superior lateral artery, a superior medial artery, an inferior medial artery, and an inferior lateral artery. The first reference coordinate R1 is closer to the nasal side than the second reference coordinate R2. That is, the second reference coordinate R2 is closer to the temporal side than the first reference coordinate R1. Next, a fundus image is obtained. This fundus image is obtained when the tracking and aiming of the first reference coordinate R1 and the second reference coordinate R2 by the composite aiming point is successful.

[0030] In one embodiment of the present invention, the optic disc cup retinal vascular target T1a and the fovea target T2a may be, but are not limited to, a ring shape, a cross ring shape, an ellipse shape, a triangle shape, an inverted triangle shape, a square shape, a diamond shape, a trapezoid shape, an inverted trapezoid shape, a hexagon shape, an octagon shape, or an X shape. For example, in the case of the X-shaped optic disc cup retinal vascular target T1b, which is an X-shape, the X-shaped optic disc cup retinal vascular target T1b is further provided with a circular target sight T11 and a forward and reverse fork sight T12.

[0031] In one embodiment of the present invention, the circular target sight T11 tracks and aims at the optic disc cup. The forward and reverse fork sight T12 further includes four branches, which are arranged radially from the circular target sight in a substantially X-shape. The four branches track and aim at the retinal vein branch or the retinal artery branch. In other words, the first branch, which is the first of the four branches, can track and aim at the superior lateral vein or the superior lateral artery, the second branch, which is the second of the four branches, can track and aim at the superior medial vein or the superior medial artery, the third branch, which is the third of the four branches, can track and aim at the inferior medial vein or the inferior medial artery, and the fourth branch, which is the fourth of the four branches, can track and aim at the inferior lateral vein or the inferior lateral artery.

[0032] In another embodiment of the present invention, if the tracking and aiming of the first and second reference coordinates R1 and R2 by the composite aiming point fails, an error message is sent, and the focal length to the fundus is evaluated by calculating the difference value with the fundus image, and the image capture unit is moved to a second test position, which is a suitable focal plane position, and the above steps are repeated to capture another fundus image.

[0033] In addition, in a further embodiment of the present invention, fundus images acquired at different time periods can be compared, in particular, images of the optic disc, retinal vein branch or retinal artery branch and fovea of ​​the fundus of an individual are compared. In this way, by comparing fundus images at different time periods, medical personnel or patients can obtain whether changes have occurred in the blood vessels of the fundus at different time periods in a simple manner or with a simple operation procedure, without the need for expensive medical examination equipment or complicated operation procedures.

[0034] The present invention also provides a system 100 for recognizing and tracking features of fundus images. For example, a simple, convenient and effective handheld mobile system is provided that allows medical personnel, others or patients with retinal disease to recognize and track features of fundus images at any place, such as a medical institution or at home. The system 100 is applicable to a handheld mobile device 101. The handheld mobile device 101 includes, but is not limited to, a smart mobile device. The system 100 includes at least an image acquisition unit 1, a fundus image database 2, a display unit 3 and a feature identification and comparison unit 4. The feature identification and comparison unit 4 is used to identify and compare the optic disc, retinal vein branch or retinal artery branch and fovea in fundus images acquired in different periods. The fundus image database 2 is used to accumulate fundus images acquired in different periods. In other words, the display unit 3 can be electrically connected to the image acquisition unit 1 and the fundus image database 2, and can transmit and display fundus images from the image acquisition unit 1, or transmit and display fundus images from the fundus image database 2. The image acquisition unit 1, the fundus image database 2, the display unit 3 and the feature identification and comparison unit 4 are mounted on a handheld mobile device and can be electrically connected to each other.

[0035] Of course, the present invention is not limited to the above, and the fundus boundary is defined based on the contrast ratio of the fundus image, and the fundus section obtained from the fundus image is selected by a circle using a ring-shaped aim point C provided on the image acquisition unit 1. Then, the feature identification and comparison unit 4 calculates whether the fundus section and the fundus image previously created by the ring-shaped aim point C meet a reference value of overlapping area. The reference value of overlapping area is at least 72%. If not, an error message can be sent from the handheld mobile device. For example, the display unit 3 can present an error message, such as an image error message, or the handheld mobile device 101 can send a voice error message, but is not limited thereto. In other words, the auxiliary method further provided by the present invention defines the fundus boundary based on the contrast ratio of the fundus image, and selects a fundus section by a circle. Then, it calculates and compares whether the fundus section and the fundus image previously created by the ring-shaped aim point C meet a reference value of overlapping area. In other words, the coverage rate of the ring-shaped aim point C can indicate whether or not there is a deviation in the aim point when the fundus image is acquired, and also indicates whether or not an appropriate focal plane exists between the image acquisition unit 1 and the fundus of the individual. EXAMPLES

[0036] Please refer to Figures 5 and 6. The optic disc cup retinal vascular target T1b and the foveal target T2b were used to track and target the first reference coordinate R1 and the second reference coordinate R2 in cooperation. In this case, tracking and targeting were successful, targeting was completed, and a fundus image was obtained. EXAMPLES

[0037] Please refer to FIG. 7. The first reference coordinate R1 and the second reference coordinate R2 were tracked and aimed in cooperation with the optic disc cup retinal blood vessel target T1b and the foveal target T2b. However, the tracking and aiming failed and the targeting could not be completed, so it was not possible to effectively obtain a fundus image. Note that the tracking and aiming could be performed by automatic tracking and aiming, semi-automatic tracking and aiming, or manual tracking and aiming.

[0038] The above describes the technical contents of the present invention through certain specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed herein. However, the present invention may be implemented or applied in a number of different forms without departing from the spirit of the present invention. [Explanation of symbols]

[0039] 100 Fundus image feature recognition and tracking system 101 Handheld Mobile Devices 1 Image Acquisition Unit 2 Fundus image database 3 Display unit 4. Feature discrimination and comparison unit 5 light source 51 Rays of light C-ring shaped aiming point E eyes R1 First reference coordinate R2 2nd reference coordinate T1a optic disc retinal vascular target T1b optic disc retinal vascular target T11 Circular Target Sight T12 Fork-type sight T2a foveal target T2b foveal target

Claims

1. 1. A method for recognizing and tracking features in a fundus image, comprising: Moving an image capture unit having a composite aim point to a first test position, the first test position allows the fundus of the individual to be located in a focal length section of the image capture unit, and the composite aim point further includes an optic disc cup retinal vascular target and a fovea target; The optic disc cup retinal vascular target is used to track and aim at a first reference coordinate of the fundus of the individual, and the foveal target is used to track and aim at a second reference coordinate of the fundus of the individual in cooperation with the foveal target, the first reference coordinate being selected from the optic disc, the retinal vein branch, or the retinal artery branch of the fundus of the individual, and the second reference coordinate is the fovea of ​​the fundus of the individual; acquiring a fundus image, the fundus image being obtained when the first reference coordinate and the second reference coordinate are successfully tracked and aimed by the composite aim point; and A method for determining a fundus boundary based on a contrast ratio of the fundus image, selecting a fundus section obtained from the fundus image by a circle using the composite aim point, and calculating whether the fundus section and the fundus image previously created at the composite aim point meet a reference value of overlap area by a feature identification and comparison unit, and the reference value of overlap area is at least 72%.

2. The method of claim 1 , wherein the optic disc further comprises an optic disc cup.

3. 3. The method of claim 2, wherein the retinal vein branch is selected from the superior lateral vein, superior medial vein, inferior medial vein, and inferior lateral vein, and the retinal artery branch is selected from the superior lateral artery, superior medial artery, inferior medial artery, and inferior lateral artery.

4. 4. The method of claim 3, wherein the optic disc cup retinal vascular target and the foveal target are ring-shaped, cross-ring-shaped, ellipse-shaped, triangular, inverted triangle, square, diamond, trapezoid, inverted trapezoid, hexagon, octagon, or X-shaped.

5. 5. The method of claim 4, wherein the optic disc cup retinal vascular target further comprises a circular target sight and a forward and reverse fork sight, the forward and reverse fork sights being radially arranged from the circular target sight in a generally X-shape.

6. The method of claim 5 , wherein the circular target aimer tracks and aims at the optic disc cup.

7. 7. The method of claim 6, wherein the forward and reverse fork sight further includes four branches, which track and aim at the superior lateral vein or artery, the superior medial vein or artery, the inferior medial vein or artery, and the inferior lateral vein or artery, respectively.

8. The method according to claim 1, wherein if the tracking and aiming of the first and second reference coordinates by the composite aiming point fails, an error message is sent, and the focal distance to the fundus is evaluated by calculating a difference value with the fundus image, and then the image acquisition unit is moved to a second examination position, which is an appropriate focal plane position, and the steps described in claim 1 are repeated to acquire another fundus image.

9. 9. The method according to claim 8, wherein the fundus images acquired at different time periods are compared, in particular images of the optic disc, the retinal vein or artery branches and the fovea of ​​the fundus of the individual.

10. 10. The method of claim 9, wherein the fundus image is first acquired by aiming a light beam at the individual's eye to assist in positioning and aiming, thereby enabling standardization of the orientation of the individual's eye.

11. 1. A system for recognizing and tracking features in a fundus image, comprising: The present invention includes an image acquisition unit, the image acquisition unit being provided with a composite aim point, the composite aim point further being provided with an optic disc cup retinal vascular target and a fovea target, the image acquisition unit moving to a first examination position, the first examination position allowing the fundus of the individual to be located within a focal length interval of the image acquisition unit, the optic disc cup retinal vascular target tracking and aiming at a first reference coordinate of the fundus of the individual, the fovea target tracking and aiming at a second reference coordinate of the fundus of the individual in cooperation with the fovea target, the first reference coordinate being selected from the optic disc, the retinal vein branch or the retinal artery branch of the fundus of the individual, the second reference coordinate being the fovea of ​​the fundus of the individual, a fundus image is acquired when the first reference coordinate and the second reference coordinate are successfully tracked and aimed by the composite aim point; The system defines a fundus boundary obtained from the contrast ratio of the fundus image, selects a fundus section obtained from the fundus image by the composite aim point with a circle, and calculates by a feature identification and comparison unit whether the fundus section and the fundus image previously created at the composite aim point meet a reference value of overlap area, and the reference value of overlap area is at least 72%.

12. 12. The system of claim 11, wherein the optic disc cup retinal vascular target further includes a circular target aimer and a forward and reverse fork aimer, the forward and reverse fork aimer being arranged radially from the circular target aimer in an approximate X-shape, the circular target aimer tracking and aiming at the optic disc cup, and the forward and reverse fork aimer further includes four branches, which track and aim at the superior lateral vein or superior lateral artery, the superior medial vein or superior medial artery, the inferior medial vein or inferior medial artery, and the inferior lateral vein or inferior lateral artery, respectively.

13. The system of claim 11, further comprising a feature identification and comparison unit, which is used to identify and compare the optic disc, retinal vein branches or retinal artery branches, and fovea in the fundus images acquired at different periods.

14. The system of claim 13, further comprising a fundus image database for storing said fundus images acquired at different time periods.

15. The system of claim 14 further comprising a display unit electrically connected to the image acquisition unit and the fundus image database, to which the fundus image is transmitted and displayed from the image acquisition unit, or to which the fundus image is transmitted and displayed from the fundus image database.

Images