WO2016193998A2

WO2016193998A2 - A hand held device to capture fundus images

Info

Publication number: WO2016193998A2
Application number: PCT/IN2016/000144
Authority: WO
Inventors: Ashish Sharma; Saranya Devi SUBRAMANIAM; I Ramachandran K; Lakshmikanthan Chinnasamy
Original assignee: Ashish Sharma
Priority date: 2015-06-05
Filing date: 2016-06-06
Publication date: 2016-12-08
Also published as: WO2016193998A3

Abstract

The present invention relates to a hand held device used to capture fundus images. More particularly the intention provides a low cost hand held device to image entire fundus either it is central or peripheral. The invention is smart phone based hand held device capable of capturing regions of peripheral most retina such as ora serrata and further till pars plana apart from central fundus. Advantageously, the present invention is operated by single hand.

Description

A HAND HELD DEVICE TO CAPTURE FUNDUS IMAGES

FIELD OF INVENTION

The present invention relates to a hand held device to capture fundus images, particularly to a low cost hand held device to image entire fundus either it is central or peripheral. More particularly, the present invention relates to smart phone based hand held device to capture regions of peripheral most retina such as ora serrata and further till pars plana apart from central fundus. Advantageously, the present invention is operated by single hand.

BACKGROUND ART

Vision is one of the most valued of human sensory experiences. Vision loss is an often feared untoward health event associated with serious medical, psychological, social, and financial consequences. The preservation of vision has thus been an important goal of health interventions and is recognized as such by the World Health Organization.

More specifically, vision loss can be caused by many factors, stemming from damage to all parts of the visual system. Retinal and optic nerve problems have emerged as leading causes of visual loss in developed countries. These posterior segment ophthalmic conditions are major and growing causes of vision loss globally, as well. Fortunately, many of these conditions, such as neovascular age-related macular degeneration, diabetic retinopathy, diabetic macular edema, proliferative diabetic retinopathy, retinal detachment, and glaucoma are treatable.

In most of these cases, early diagnosis and proper follow up leads to adequate maintenance of visual function for life. Visualization of the retina and optic nerve by expert clinical readers is currently required to identify these pathologic changes, and the timely initiation of interventions for these back of the eye conditions is paramount to preserving vision. Furthermore, the early diagnosis of conditions such as diabetic retinopathy, age-related macular degeneration, retinopathy of prematurity can help patients address risk factors for progression and thereby delay and possibly prevent long term visual loss. Generally, a retinal examination is performed by a trained clinician. The findings of the examination are then optimally documented through fundus photography. Bulky, expensive table-top fundus cameras are typically used to acquire high quality true-color images of the retina with small fields of view. The operation of these table-top cameras is very elaborate, and requires a highly trained technician. A number of hand-held fundus cameras have also been developed in the past, including a contact type camera.

These cameras, while having a smaller form-factor than the table-top devices, still lack the simplicity and portability of a device amenable to widespread distribution. The hand held units, in these cameras are bulky and are attached to a base-station via a thick cable. Alignment and focusing of the cameras is not intuitive, and in some versions the size of the field of view is inadequate. In addition, these cameras do not provide a significant reduction in cost, while lacking the imaging quality of the table-top cameras.

Smart phone has revolutionized the fundus imaging in recent past. It started with use of capturing images with the smart phone and slit lamp. Researchers have been successful in making indirect smart phone based devices and technique with the ability to image limited area of fundus in recent past. Perhaps previous researchers who belonged to the developed world made a sincere effort to help developing countries by exploring a mass screening tool in the form of the smart phone based indirect fundus camera.

In developing country such as India much wider need of the smart phone based inexpensive portable device which could be capable of imaging central and periphery of retina is very much required. In a country like India many retina practitioners and other comprehensive ophthalmology practitioners find it difficult to fund themselves to buy costly fundus cameras in the beginning of their practice. In developing countries there are multiple solo clinics across the countiy and due to un affordability to buy high cost fundus cameras, most of the times diagnosis and documentation of retinal pathologies take a back seat. This affects the overall quality of ophthalmic care across the country. There are smart phone based fundus imaging device known in the art but none of them could demonstrate the ability to capture peripheral images. One such smart phone based fundus imaging device needed one hand to support 20 D lens and other hand to handle smart phone hence there was no hand available for indentation.

Accordingly there is a need to develop a cost effective light weight device with the imaging technique that can image regions of peripheral most retina such as ora serrata and further till pars plana apart from central fundus so that it will be easy to handle, more particularly with a single hand.

There is another need to develop a smart phone based hand held device which will be able to image central and periphery with such an inexpensive manner opens up many possibilities such as; to practice evidence based medicine by showing peripheral lesions to the patients that clinician wants to treat, to monitor disease and treatment response in cases multiple retinal diseases, to be used in bedridden patients, children with special needs, portability to use it in multiple clinics covered by clinicians, mass screening for retinal diseases and for teaching institute in the form of teaching by easy demonstration rather theoretical description.

OBJECTS OF INVENTION

One or more of the problems of the conventional prior art may be overcome by various embodiments of the present invention.

It is the primary object of the present invention to provide a low cost hand held device to image entire fundus either it is central or peripheral.

It is another object of the present invention to provide a smart phone based hand held fundus imaging device, which is operated in single hand. The device could be held by one hand , and operated such that the other hand is available for other activities such as indentation.

It is another object of the present invention, wherein the hand held device images regions of peripheral most retina such as ora serrata and even further till pars plana apart from central fundus. It is another object of the present invention, wherein the hand held device transmits the images to the required destinations/data storage devices.

It is another object of the present invention, wherein the hand held device records the data in image format or in video format. SUMMARY OF INVENTION

Thus according to the embodiment of the present invention there is provided a hand held device to capture fundus images comprising of a stem, a lens holder, a mobile holder, a lens and a smart phone having at least one camera. wherein the stem is having an upper end and a lower end wherein the mobile holder fitted with smart phone having at least one camera is mounted at the upper end of the stem and wherein the lens holder fitted with the lens is mounted at the lower end of the stem.

It is another aspect of the present invention, wherein the upper end having an upper flange and the lower end having a lower flange are connected by a curved portion of pre determined radius and arch length.

It is another aspect of the present invention, wherein the upper flange is provided with one or more threaded holes of pre determined size which are arranged at pre determined location for detachably mounting the mobile holder.

It is another aspect of the present invention, wherein the lower flange comprises a threaded hole of pre determined size arranged at a pre determine location for the fitment of the lens holder with the stem.

It is another aspect of the present invention, wherein the lower flange comprises a radial recess of pre determined dimension and is disposed to locate and guide the cylindrical guide portion provided in the lens holder. It is another aspect of the present invention, wherein the lens holder comprises a base portion, a cylindrical shaped lens holding portion, a fork portion, a stepped portion and an eye portion.

It is another aspect of the present invention, wherein the eye portion is provided with a cylindrical passage opening of pre detennined diameter which is disposed for accommodating the threaded portion of the knob provided for detachably connecting the lens holder and the stem.

It is another aspect of the present invention, wherein the guide portion of pre determined dimensions is arranged at the base portion of the lens holder at a pre determined distance from the centre of the cylindrical passage opening in the longitudinal direction such that the lens holder could freely swing within the radial recess provided on the lower flange of the stem.

It is another aspect of the present invention, wherein the mobile holder comprises a fixed holder and a movable holder, while the fixed holder is fixed with the upper end of the stem, the moveable holder is slide ably mounted within the fixed holder to facilitate holing of the mobile phone.

It is another aspect of the present invention, wherein the movable holder is pressed in the direction towards the fixed holder using a compression spring to enable holding of the. smart phone between the fixed mobile catch and the moveable mobile catch fitted with grips.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 of the drawings schematically illustrates the perspective view of the apparatus according to the invention shown without the lens and the smart phone.

Figure 2 of the drawings schematically illustrate the perspective view of the stem according, to the invention.

Figure 3 of the drawings schematically illustrate the bottom view of the stem according to the invention

Figure 4 of the drawings schematically illustrate the side view of the lens holder according to the present invention. Figure 5 of the drawings schematically illustrate the bottom view of the lens holder according to the present invention.

Figure 6 of the drawings schematically illustrate the top view of the mobile holder according to the present invention.

Figure 7 of the drawings schematically illustrate the top view of the fixed holder according to the present invention.

Figure 8 of the drawings schematically illustrate bottom view of the fixed holder according to the present invention.

Figure 9 of the drawings schematically illustrate the top view of the moveable holder according to the present invention. Figure 10 of the drawings schematically illustrate the bottom view of the moveable holder according to the present invention.

Figure 1 1 of the drawings schematically illustrate the perspective view of the knob according to the present invention.

Figure 12 of the drawings schematically illustrate the perspective view of the cover according to the present invention

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES

The present invention is thus directed to a smart phone based hand held device to capture regions of peripheral most retina such as ora serrata and further till pars plana apart from central fundus.

Referring to Figure 1 , the hand held device to capture fundus images comprises a stem ( 1); a lens holder (2) to hold a lens; a mobile holder (3) to hold a smart phone; and a knob (4). Referring to Figure 2, upper end ( la) of the stem ( 1) is provided with an upper flange (lc) of pre-determined thickness and lower end ( lb) of the stem (1) is provided with a lower flange (Id) of pre- determined thickness. The upper flange (lc) and the lower flange ( Id) are arranged at a pre determined angle to each other and connected by a curved portion (le) of pre determined radius and arch length. The upper flange (lc) is provided with one or more threaded holes (If) of pre determined size for detachably mounting the mobile holder (3) .

As shown in figure 3, the lower flange (Id) is provided with a threaded hole (I f) of pre determined size arranged at a pre determine location which is disposed for the fitment of the lens holder (2) with the stem (1) at required orientation with respect to the smart phone fitted on the mobile holder (3). Advantageously, the threaded inserts may be provided at pre determined location during the moulding process instead of providing threaded holes (lf, l ).

The lower flange (Id) is further provide with a blind, oblong shaped radial recess (lg) of pre determined radial distance, width, arc length and depth which is disposed to locate and guide the cylindrical guide portion (2h) provided in the lens holder (2). The bottom wall surface of the radial recess (lg) is provided with an array of serrations which are disposed to provide controlled movement of the lens holder. In order to have sufficient structural strength, the stem (1) is constructed with cross section which is approximately in the shape of U. The stem (1) is preferably made of polymeric material of sufficient strength, such as Acrylonitrile Butadiene Styrene (ABS) and may be conveniently made by injection moulding process.

As shown in figure 4 and 5, the lens holder (2) comprises a base portion (2a), a cylindrical shaped lens holding portion (2b) of pre determined diameter having a stepped portion (2c) which is arranged to retain the lens at the pre determined location. The lens holding portion (2b) comprises a fork portion (2d) to facilitate easy fixing and removal of the lens. The lens holding portion (2b) and the base portion (2a) are connected by a curved portion (2e) having a radius equal to that of the radius of the curved portion (le) of the stem (1). An eye portion (2f) is arranged within the U shaped curved portion (2e) and provided with a cylindrical passage opening (2g) of pre determined diameter which is disposed for accommodating the threaded portion (4b) of the knob (4) provided for detachably connecting the lens holder (2) and the stem (1).

An outwardly projecting cylindrical guide portion (2h) is arranged at the base portion (2a) of the lens holder (2). The cylindrical guide portion (2h) is arranged at a pre determined distance from the centre of the cylindrical passage opening (2g) in the longitudinal direction and has pre determined diameter and height. The diameter of the guide portion (2h) is selected such that it could move freely within the radial recess (lg) provided on the lower flange (Id) of the stem (1). The lens holder (2) can be swivelled in radial direction and clamped with the stem (1) to obtain the required orientation between the lens fitted to the lens holder (2) and optical axis of the camera lens of the smart phone facing the lens holder (2) is in line with the optical axis of the concave lens fitted to the lens holder (2). The lens holder (2) is preferably made of polymeric material of sufficient strength, for example Acrylonitrile Butadiene Styrene (ABS) and may be conveniently made by injection moulding process.

As shown in figure 6, the mobile holder (3) comprises a fixed holder (3a) and a movable holder (3b). While the fixed holder (3a) is fixed with the upper end (la) of the stem (1), the moveable holder (3b) is slide ably mounted within the fixed holder (3a) to facilitate holing of the smart phone. For simplicity and ease of manufacture the fixed holder (3a) of the mobile holder (3) is made as a separate part and fixed with the stem (1). However it is to be understood that it is possible to construct the stem (1) and the fixed holder (3a) of the mobile holder (3) as an integral part.

The fixed holder (3a) comprises fixing portion (3a 1) and having one or more fixed mobile catch (3a2) extending in vertical direction as shown in figure 7. A recess portion (3a3) is provided at the bottom side of the fixing portion (3a 1) to facilitate locating and accommodating the upper flange portion (lc) of the stem (1). The fixing portion (3a 1) further comprises one or more fixing holes (3a4) arranged suitable for accommodating countersunk screw. The fixed holder (3a) further comprises a guiding portion (3a5) disposed to accommodate and retain the moveable holder (3b).

As shown in figure 7, the guiding portion (3a5) comprises one or more guides (3a6) and a recess portion (3a7) to accommodate a compression spring (5). The guiding portion (3a5) lies adjacent to the fixing portion (3al) at a lower level and is arranged parallel to the fixing portion (3al). The recess portion (3a3) further provided with fixed spring guide (3a8) to retain the compression spring (5). The fixed spring guide (3a8) is located within the recess portion (3a3) and extends in direction towards the moveable holder (3b). The fixed holder (3a) is preferably made of polymeric material of sufficient strength, for example Acrylonitrile Butadiene Styrene (ABS) and may be conveniently made by injection moulding process. As shown in figure 9 and 10, the movable holder (3b) comprises a sliding portion (3bl) and having one or more moveable mobile catch (3b2) extending in vertical direction. The bottom side of the sliding portion (3b 1) is provided with one or more guides (3b3) to facilitate locating and sliding within the guiding part (3a5) of the fixed holder (3a). The bottom side of the sliding portion (3b 1) is further provided with spring guiding portion (3b4) extending in down ward direction and provided with the moveable spring guide (3b5). The moveable spring guide (3b5) is cylindrical in shape and has pre determined diameter and extends in direction towards the moveable mobile catch (3b2). The movable holder (3b) is preferably made of polymeric material of sufficient strength, for example Acrylonitrile Butadiene Styrene (ABS) and may be conveniently made by injection moulding process.

Reference is invited to figure 6, 7 and 8 of the drawings, the movable holder (3b) is slide ably fitted to the fixed holder (3a), the compression spring (5) is assembled in the recess portion (3a3) and held by the fixed spring guide (3a8) and the moveable spring guide (3b5) such that the movable holder (3b) is pressed in the direction towards the fixed holder (3a) to enable holding of the smart phone between the fixed mobile catch (3a2) and the moveable mobile catch (3b2). The fixed mobile catch (3a2) and the moveable mobile catch (3b2) are fitted with grips (7) made of soft material such as syntactic rubber to prevent the possible damage to the smart phone. The movement of the movable holder (3b) towards the fixed holder (3a) is limited by the vertical wall that connects the fixing portion (3a 1) and a guiding portion (3a5). After the assembly the exposed part of the sliding portion fitted with the compression spring (5) is covered by a cover (6) as shown in figure 6.

The cover (6) shown in figure 12 is prefe ably made of polymeric material, for example Acrylonitrile Butadiene Styrene (ABS) and may be conveniently made by injection moulding process. The cover (6) may be detachably mounted with the help of one or more counter sunk screws or pasted using adhesive. The mobile holder (3) is fitted to the upper end (la) of the stem (1) and the smart phone is mounted between the fixed mobile catch (3a2) and the moveable mobile catch (3b2). The lens holder (2) mounted with lens is fitted to the lower end (l b) of the stem and swivelled until the required orientation is obtained between the lens and the lens fitted in the smart phone and clamped with the help of the knob (4). As shown in figure 1 1 , The knob (4) comprises a head portion (4a) and a threaded portion (4b) provided with a circlip groove located at a pre determined distance from the head portion (4a) for fixing a circlip in order to prevent , the accidental fall of the lens holder during the adjustment. The head portion of the knob (4a) can be conveniently made of synthetic material and can be moulded with the threaded portion (4b) made of metallic material. The combination of the serration arranged in the recess portion (lg) of the stem (1 ) and the cylindrical guide portion (2h) of lens holder (2) provides controlled movement of the lens holder during the orientation of the lens fitted to the lens holder (2) and the lens fitted in the smart phone. While the device so arranged could be conveniently held by one hand of the user, the other hand is free for other activities associated with the examination of the eye. The another advantage of the hand held device to capture fundus images according to the present invention is that it is possible to use the lens and smart phones normally in use by the oophthalmologists. Hence the cost of the hand held device to capture fundus images according to the present invention is extremely low as compared to the similar devices known in the art. The smart phone can be advantageously loaded with exclusive applications for ease of operation, communication, storage and retrieval of the data.

Though this invention is hereinbefore described and illustrated with reference to specific embodiments, obvious alterations and modifications known to persons skilled in the art are well within the scope of the appended claims.

Claims

I CLAIM:

1. A hand held device to capture fundus images comprising of:

a stem (1);

a lens holder (2);

a mobile holder (3);

a lens; and

a smart phone having at least one camera,

wherein the stem is having an upper end (la) and a lower end (lb), wherein the mobile holder (3) fitted with smart phone having at least one camera is mounted at the upper end (la) of the stem (1), and

wherein the lens holder (2) fitted with the lens is mounted at the lower end^'

(lb) of the stem (l).

2. The device as claimed in claim 1, wherein the upper end (la) having an upper flange (lc) and the lower end (lb) having a lower flange (Id) are connected by a curved portion (le) of pre determined radius and arch length.

3. The device as claimed in claim 2, wherein the upper flange (lc) is provided with one or more threaded holes ( 1 f) of pre determined size which are arranged at pre detennined location for detachably mounting the mobile holder (3).

4. The device as claimed in claim 2, wherein the lower flange (Id) comprises a threaded hole (If) of pre detennined size arranged at a pre determine location for the fitment of the lens holder (2) with the stem (1).

5. The device as claimed in claim 2 and 4, wherein the lower flange (Id) comprises a radial recess (lg) of pre determined dimension and is disposed to locate and guide , the cylindrical guide portion (2h) provided in the lens holder (2).

6. The device as claimed in claim 1, wherein the lens holder (2) comprises a base portion (2a), a cylindrical shaped lens holding portion (2b), a fork portion (2d), a stepped portion (2c) and an eye portion (2f)-

7. The device as claimed in claim in 1 and 6, wherein the eye portion (2f) is provided with a cylindrical passage opening (2g) of pre determined diameter which is disposed for accommodating the threaded portion (4b) of the knob (4) provided for detachably connecting the lens holder (2) and the stem (1).

8. The device as claimed in claim 6, wherein the guide portion (2h) of pre determined dimensions is ananged at the base portion (2a) of the lens holder (2) at a pre determined distance from the centre of the cylindrical passage opening (2g) in the longitudinal direction such that the lens holder (2) could freely swing within the radial recess (lg) provided on the lower flange (Id) of the stem (1).

9. The device as claimed in claim 1, wherein the mobile holder (3) comprises a fixed holder (3 a) and a movable holder (3b), while the fixed holder (3 a) is fixed with the upper end (la) of the stem (1), the moveable holder (3b) is slide ably mounted within the fixed holder (3a) to facilitate holing of the smart phone.

10. The device as claimed in claim 9, wherein the movable holder (3b) is pressed in the direction towards the fixed holder (3a) using a compression spring (5) to enable holding of the smart phone between the fixed mobile catch (3a2) and the moveable mobile catch (3b2) fitted with grips (7).