WO2019234218A1

WO2019234218A1 - Plácido's discs cone-projector

Info

Publication number: WO2019234218A1
Application number: PCT/EP2019/064939
Authority: WO
Inventors: Roberto Gustavo Albertazzi
Original assignee: Roberto Gustavo Albertazzi
Priority date: 2018-06-08
Filing date: 2019-06-07
Publication date: 2019-12-12

Abstract

Plácido's discs cone–projector of reduced size that can be used in an assembly of corneal topography that, in turn, can be coupled for use with different medical devices or instruments, whereby this assembly can also conform a manual device of corneal topography.

Description

PLACIDO’S DISCS CONE-PROJECTOR

FIELD OF THE INVENTION

The present invention relates to the field of medical devices or instruments, more particularly to the ophthalmological area, and more precisely refers to a Placido’s discs cone-projector with reduced size for devices that allow corneal topographies and can be used in already existing medical devices, such as a surgical microscope, as well as can also form an assembly or device for manual and transportable use, assisted with cell phone mobile devices, or similar, or others known more popularly as "smartphones".

BACKGROUND OF THE INVENTION

The corneal topography is a diagnostic study that allows knowing, through its realization, the characteristics of the cornea, i.e., the tissue that covers the anterior and exterior part of the eye of the patient on which the study is carried out. The technique consists in carrying out a study of the curvatures of the cornea surface to analyze if there are irregularities, asymmetries and to know the different degrees of curvature of this tissue that is essential for vision due to its optical properties of refraction. What you get with this study is a kind of "three-dimensional map" of the cornea, a representation of the corneal surface that marks its curvatures, elevation, dioptric power and relief making maps that facilitate their understanding.

The study is fundamental for multiple purposes such as the per- surgical evaluation of a patient or to help choose the correct dioptric measurement in the surgery of implantation of an intraocular lens, for subsequent follow-up of these surgeries, for design of contact lenses, etc. It could be said that the corneal topography began with the Portuguese ophthalmologist Antonio Placido, who in 1880, viewed a painted disc of different alternating black and white rings reflected in the cornea, and these rings shown as contour lines projected on the corneal tissue. More precisely, they were projected by projecting annular images of known dimensions on the anterior corneal surface. Using these rings in an ophthalmometer and photographing the image, he was able to analyze it to obtain, in principle, the corneal curvature. Over time, with new technologies, it was possible to arrive until today where the images of the rings are processed by computers, algorithms and systems that by means of existing mathematical relationships between reflected rings and the shape of the cornea, transform the data obtained from the images in radii of curvature, powers or elevations of the corneal surface, always taking into account the refractive indexes.

A conventional corneal topographer consists of a voluminous tabletop apparatus in front of which the patient to whom the study will be performed is sitting. The patient rests the chin on a chin bar and the light ring pattern is centered on the anterior surface of the patient's cornea and reflected to a digital camera inside the device. The topology of the cornea is revealed by the shape taken by the reflected pattern. A computer provides the necessary analysis, typically determining the position and height of several thousand points across the cornea and the topographic map is represented in a number of graphic formats, the curvature inclination being coded in colors according to the dioptric value of the same. Even when the service, operation and function of these devices in health institutions have always been effective, they require the patient to go to study centers, laboratories, clinics and hospitals to be able to study.

In light of this state of the art, it would be very convenient to have a new technology and instruments to deal with cases where the patient cannot move from home or is in bed in a hospital and cannot go and sit in front of a table corneal topographer. It would be very convenient to have a new device or topographer for ambulatory studies, either to study a patient lying down or at home where transporting a conventional topographer would entail costs that cannot be absorbed by public welfare institutions. In addition, it would be convenient to have a corneal topographer that due to its design and size could be used to work with other medical devices or instruments such as a surgical microscope and can even be part of the armamentarium of the ophthalmological examinations that are necessary in Pediatrics.

SUMMARY OF THE INVENTION

It is then an object of the present invention to provide a new cone- projector of small Placido’s discs that allows the projection of said discs on the eye of a patient to carry out the topography thereof.

It is still another object of the present invention to provide a Placido’s discs cone-projector having an inner cone inverted with respect to the outer structural configuration, which has a plurality of light and shadow rings.

It is also another object of the present invention to provide said inverted inner cone that has a painted interior and machined sections for the passage of light. It is still another object of the present invention to provide said inverted inner cone having said machined sections forming light surfaces combined with shadow surfaces, which together satisfactorily allow to project the Placido’s discs onto the patient's eye.

It is another object of the present invention to provide said inverted inner cone that also has a new relationship in the separation distance between rings.

It is therefore an object of the present invention to provide a device for performing corneal topographic studies that is comprised of a simple, manual and transportable use assembly to be able to treat patients in a state of bed rest and home patients and that uses the reduced size cone-projector according to the present invention.

It is also an object of the invention to provide a new corneal topographer that uses the disc cone-projector of the invention, for manual use, simple and inexpensive that does not incorporate any camera but can be used with any cell phone or Smartphone owned by the same ophthalmologist who performs the study, whereby public institutions avoid the expensive investment that implies the acquisition of a conventional topographer.

It is also an object of the present invention to provide a new assembly of corneal topography using the small cone-projector of the invention and which, due to the simplicity and size thereof, can be coupled to existing medical instruments, such as a surgical microscope, which allows to observe in situ the annular images generated by the device in the cornea.

It is further an object of the present invention to provide a Placido’s discs cone-projector comprising an external part whose smaller diameter is oriented towards one of the eyes of a patient, while the larger diameter is oriented towards a light source; and an inner cone inverted and concentric with respect to the external part, which has a greater diameter oriented towards one of the eyes of a patient, and a smaller diameter oriented towards a light source, being provided along its length with at least a plurality of grooved rings of light that are separated by shadow rings, each grooved ring of light having an upper face of light passage whose perimeter is stepped in a triangular shape defining a surface of light, and having said shadow rings a shadow surface contiguous to the light surface, and where there is a growth rate of between 1.22% and 1.16% between rings, so that it moves away and enlarges more to the extent that each ring takes distance from the base or the supporting point of the eye.

It is yet another object of the present invention to provide a portable corneal topographer using the discs cone-projector and comprising a conical container module having a top end connectable to a mobile phone (cell phone) support and a lower end of a lower diameter that is oriented towards the patient's eye, both ends being open and inside which are arranged at least said

Placido’s discs cone-projector, a light diffuser panel arranged above said discs projector, a printed circuit arranged upstream of the light diffuser panel, a light box containing said printed circuit, and a closing element.

DESCRIPTION OF THE DRAWINGS

For greater clarity and understanding of the subject matter of the present invention, it has been illustrated in several Figures, in which the same has been represented in one of the preferred embodiments, all by way of example, wherein: Figure 1A is a sectional view of the small Placido’s discs cone- projector in conjunction with an eye of a patient according to the present invention;

Figure 1 B is a sectional and enlarged view of the Placido’s discs cone-projector according to the present invention;

Figure 2 is a perspective view taken from below of a portable corneal topographer and using the discs cone-projector of Figure 1 according to the present invention;

Figure 3 is a perspective view taken from above of the portable corneal topographer of Figure 2;

Figure 4 is a side view of the portable corneal topographer of Figure

2;

Figure 5 is a front view of the portable corneal topographer of Figure

2;

Figure 6 is a side and sectional view of the portable corneal topographer of Figure 2;

Figure 7 is a perspective and exploded view of the portable corneal topographer according to the present invention;

Figure 8 is a perspective view taken from below of an assembly of corneal topography placed in a surgical microscope, according to a preferred embodiment of the invention; and

Figure 9 is a perspective view taken from below and in exploded view of the assembly of corneal topography and surgical microscope of Figure 1 . DETAILED DESCRIPTION OF THE INVENTION

Referring to the Figures, it is observed that the invention proposes a new Placido’s discs cone-projector of reduced size, Figures 1A and 1 B, which can be used in an assembly of corneal topography that, in turn, can be coupled for use with different medical devices or instruments, Figures 8 and 9, wherein said assembly can also conform a manual device for corneal topography, Figures 2 to 7. The Placido’s discs cone-projector of reduced size allows to solve surprisingly all the drawbacks that are presented in the prior art with respect to conventional topographers.

According to Figures 1A and 1 B, there is provided a Placido’s discs cone-projector which is indicated by the general reference 1 and comprises an external part 2 whose smaller diameter 3 is oriented towards one of the eyes 4 of a patient, while the larger diameter 5 is oriented towards a light source which will be described below. Moreover, the external part 2 comprises an upper surface 6 which has a light distribution curvature that allows the adequate distribution of light inside the cone-projector 1 to help with the correct posterior projection of the Placido’s rings on the eye 4 of the patient.

Likewise, said cone-projector 1 is provided with an inner cone 7 inverted and concentric with respect to the external part 2, which has a larger diameter 8 oriented towards one of the eyes 4 of a patient, and a smaller diameter 9 oriented towards a light source that will be described below. As can be seen in Figure 1A or 1 B, said upper surface 6 is in the same plane as the smaller diameter 9 of the inner cone 7 and larger diameter 5 of the external part 2 of the cone-projector. Meanwhile, said inner cone 7 is provided along its length with at least a plurality of grooved light rings 10 that are separated by shadow rings 11 , each grooved light ring 10 having an upper face of light passage 12 whose perimeter is stepped in triangular shape defining a light surface 13, and said shadow rings 11 having a shadow surface 14 contiguous with the light surface 13. Likewise, it is provided said inner cone 7 of at least one rectangular cross section 15 in a portion of the area of its larger diameter 8 that allows projecting a positioning indicator or reference.

It is emphasized that said cone-projector 1 is made of polished optical acrylic. In turn, said inner cone 7 is painted, preferably black but not limited for the invention, while each one of said stepped perimeters in triangular shape defining the light surface 13 is machined. The machining of the stepped perimeters in a triangular shape that define the light surface 13 allows the light to pass only through them since the rest of the cone is painted or "darkened". In this way, the light passes through the cone and allows the discriminated projection between rings of light and shadow on the patient's eye.

The projection of rings of light and shadow on the human eye is the principal means by which the topography thereof can be carried out as described in the prior art. Nowadays, conventional topographers, as presenting large dimensions, make the ring configuration and distribution within the cone- projector much more practical and easy for the final assembly thereof. However, the inventor has found that if someone wants to reduce the dimensions of the ring cone-projector, the relation between spacing distance and number of rings used does not remain constant. That is, if a conventional topographer is taken and the distance separation ratios between rings are obtained and the number of rings used, these relations are not kept constant when they are to be brought to a small cone-projector.

The inventor has noticed that if someone wants to maintain the relationship between distance of separation and number of rings, the tests resulted in "plastered" projections or shadow rings superimposed on the human eye where it was impossible to distinguish rings of light and rings of shadow. When the relationship between the separation distance of the rings and the amount to be used was not kept constant, depending on the dimensions of the Placido’s discs cone-peojector, there was a great hindrance to the realization of a cone-projector of reduced dimensions to improve the processes of topography in situ. Consequently, maintaining the relationships of distance and quantity in the first instance did not result in the moment of putting it into practice.

As a result of the above drawback, the inventor has encountered countless tests and errors to arrive surprisingly to the results obtained in the present invention. As described above, the inner inverted cone 7 has triangular "steps" that are machined to define light surfaces 13. The form, preferably but not limited for the invention, is of the scalene type. These light surfaces 13 allow light to pass only through them and combined with a new relationship in the separation distance between rings, which has no relation with any conventional topographic type for the reasons explained above, make it possible to surprisingly project the Placido’s discs on the patient's eye without this projection being affected or "plastered".

For this, the inventor found that there is a growth rate of about 1.22 and 1.16 between rings, so that it moves away and enlarges more as each ring takes distance from the base or the supporting point of the eye. That is, Figure 1 B, the second ring 16 is about 1.22% further than the first one of the base 17 (or the supporting point of the eye), and the last ring 18 is about 1.16% further than penultimate ring 19 on a decreasing scale. This scale has a relation between the curvature of the eye and the angle of the inner face of the cone and has allowed to successfully project the Placido’s rings on the eye using a cone of small size. It is noted that, preferably but not limited for the invention, approximately 17 light rings and approximately 17 shadow rings have been used.

In this way, the inventor has surprisingly solved the drawback in the ring distribution and the way in which Placido’s discs can be viewed discriminately between light and shadows rings on the human eye using a cone-projector of reduced dimensions. Thus, the small-sized Placido’s discs cone-projector of the present invention satisfactorily and surprisingly solves the aforementioned drawbacks.

On the other hand, the cone-projector of the present invention can be used to perform corneal topographic studies in combination with a simple, manual and transportable use assembly to be able to treat patients in a state of bed rest and home patients, such as a Smartphone or cell phone owned by the same professional ophthalmologist who performs the study, whereby public institutions avoid the expensive investment that implies the acquisition of a conventional topographer.

According to Figures 2 to 7, the cone-projector 1 of the present invention can be used in a portable corneal topographer which is indicated by the general reference 201. It is emphasized that the cone-projector 1 will keep the reference numbers described above, while reference numbers from 200 will be used for those parts corresponding to the portable topographer.

Thus, the portable corneal topographer 201 of the invention has a conical shaped container module 202 having an upper end 203 connectable to a mobile phone (cell phone) support 204 and a lower end 205 of smaller diameter that is oriented towards the eye 206 of the patient, both ends being open, wherein said upper end 203 of said container module 202 has a pair of locking tabs 207 that fit into respective locking grooves 208 provided in said mobile phone support 204. In turn, at least one light button 209 is presented, and it can be seen in Figure 6 that said lower end 205 ends even more closed to allow its contact with the eye 206 of the patient.

The container module 202 has internally at least said Placido’s discs cone-projector 1 , a light diffusing panel 210 disposed above said discs cone- projector 1 , a printed circuit 211 comprising an LED light 212 and a battery 213 disposed upstream of light diffuser panel 210, a light box 214 containing said printed circuit 211 , and a closing element 215 which can be a rubber ring so that the contained elements are retained inside the container module 202. The LED light 212 allows the generation of a beam of light that projects towards the inner inverted cone 7 so as to allow the projection of the Placido’s discs on the patient's eye as described above.

It is emphasized that, to facilitate the tasks during the topography, the container module 202 presents externally at least one outer line 216 for the positioning of the cone with respect to the reference points in the eye. In turn, the mobile phone, Smartphone or cell phone 217 may be protected by a sterile cover or shell 218 capable of operating in conjunction with sterile surgical instruments during per-surgical procedures. Likewise, it can be observed that each of the elements is adapted to present a central hole to allow taking of photographs or live view through the cell phone camera 217.

It is further noted that the mobile phone support 204 is intended to receive and retain a cell phone or Smartphone 10. The support 204 may have any form suitable for receiving phones of any type and model, and has a portion wherein the locking arrangement 208 and a central hole 219 intended to be mechanically coupled (with the container module 202) and optically with the LED light 212 are located. The mechanical coupling is to ensure a solid binding with the container module 202 and the optical coupling is to guarantee that the light or images reflected / refracted by the cornea reach the lens or viewer of the telephone 217 through the hole 219 specially designed to accommodate the position and type of viewer that has the telephone model attached to the support. The hole 219 of the support 204 will be optically aligned with the corresponding central holes mentioned above of each element of the cone- projector of the present invention.

Thus, the portable corneal topographer of Figures 2 to 7, which uses the novel cone-projector 1 of reduced size of Figures 1A and 1 B, can be used in current surgical techniques to improve them, thus obtaining better results and avoiding re-interventions not only expensive but also complicated. In this way, the professional can use the topographer of the invention in a portable manner to attend to any urgency that appears inside and / or outside the doctor’s office, and also during per-surgical processes.

The portable corneal topographer 201 attached to the cell phone 217, will project images on the anterior corneal surface of the eye 206 and the same will be taken by the telephone that will be able to store them for later use or send them to a processor to be interpreted, graphed, etc. With the computer the images can be processed by means of a software designed for that purpose. As explained, the cone-projector 1 projects the images of the rings with their own lighting, and that surround the hole or viewer that the cell phone has to obtain photographs. As has also been explained in relation to the technique of corneal topography, the purpose of projecting these rings on the corneal surface is to obtain a map of elevation, curvatures and irregularities of the corneal surface.

On the other hand, it is also an object of the present invention to provide a set of corneal topography 301 which, due to its simplicity and size, can be coupled to existing medical instruments, such as a surgical microscope 302, which allows observation of the annular images in situ generated by the device in the cornea. It is noted that the cone-projector 1 will maintain the reference numbers described above, while reference numbers from 300 will be used for those parts corresponding to the corneal topographer and medical instruments.

Thus, according to the illustrations in Figures 8 and 9, the assembly of the invention, indicated with the general reference 301 , can be used in a surgical microscope indicated with the general reference 302. The microscope 302 can be of any known type, for which reference will not be made in detail, it will only be indicated that the microscope can have a connection socket 303 that allows the assembly of e.g. magnification lenses, magnifying glasses, slides, etc. In said connection socket 303, the assembly 301 of the invention can be assembled, which is composed of a light reflector / projector 304 coupled to a carrier housing 305 that contains within the cone-projector of light rings 1 described above and illustrated in Figures 1A and 1 B, and an eyepiece 306 ergonomically shaped for the patient's face.

The light reflector / projector is a unit that includes a light source of any suitable nature, such as, for example, LED light, and a power source such as one or more batteries, to power the light source. At its periphery there is a light switch 307 for turning on and off the light source.

The cone-projector 1 of light rings has an inner conformation that allows to project the light according to the annular pattern used in the corneal topography techniques, on the cornea of the patient. These images are composed of concentric rings of predetermined diameters and are obtained from the light source that has the projector 304, or even the same cone 1 , powered by the integrated energy to the assembly. Although the cone 1 is illustrated and named with the term cone, the shape of the cone is not limited to that geometric figure but can take other different forms. Finally, at the distal end of the cone, i. e., the one facing the patient under study, it has an eyepiece that accommodates the patient's facial ergonomics.

In this way, the inventor of the present invention has surprisingly found the way to reduce the Placido’s discs cone-projector and be able to project said rings on the patient's eye without any inconvenience, thus improving the per-surgical processes and thus obtaining greater practicality, ease and safety of use, allowing additionally to reduce the related costs since it does not require big equipment, and it offers greater practicality, flexibility to the professionals to be able to realize the topography in any similar place. In addition, the drawback of the prior art is solved where projecting a metallic cone with steps under the microscope to see the deformation that the image makes on the cornea is a procedure described a long time ago that fell into disuse due to the fact that the image is very small, illegible and difficult to interpret and only represents large corneal alterations, not always easy to interpret. By means of the discs cone-projector of reduced size according to the invention, a cone with own light is created able to computerize the image obtained, providing an extremely useful, novel tool and easy to interpret for any person, with surgical experience or not, besides leaving a document in the surgical protocol. Thus, the invention can be used in all surgeries that refractively modify anterior corneal curvatures, intracorneal rings, lamellar or penetrating grafts, limbal relaxing incisions, among others.

Claims

1. A Placido’s discs cone-projector characterized by comprising:

an external part whose smaller diameter is oriented towards one of the eyes of a patient, while the larger diameter is oriented towards a light source; and an inner cone inverted and concentric with respect to the external part, which has a greater diameter oriented towards one of the eyes of a patient, and a smaller diameter oriented towards a light source, being provided along its length with:

at least a plurality of grooved light rings that are separated by shadow rings, each grooved light ring having an upper face for light passage whose perimeter is stepped in a triangular shape defining a light surface, and having said shadow rings a shadow surface contiguous with the light surface, and

wherein there is a growth rate between 1.22% and 1.16% between rings, in such a way that it moves away and enlarges more as each ring takes distance from the base or from the supporting point of the eye.

2. Placido’s discs cone-projector according to claim 1 , characterized in that the second ring is 1.22% further than the first one of the base or the supporting point of the eye, and the last ring is 1.16% further than the penultimate on a decreasing scale.

3. Placido’s discs cone-projector according to claim 1 or 2, characterized in that the number of light rings is of about 17.

4. Placido’s discs cone-projector according to claim 1 or 2, characterized in that the number of shadow rings is of about 17.

5. Placido’s discs cone-projector according to claim 1 , characterized in that it externally comprises an upper surface having a light distribution curvature, said upper surface being in the same plane as the smaller diameter of the inner cone and larger diameter of the external part of the cone-projector.

6. Placido’s discs cone-projector according to claim 1 , characterized in that said inner cone has a rectangular cross section in a portion of the area of its largest diameter.

7. Placido’s discs cone-projector according to any of the preceding claims, characterized in that the cone-projector is made of polished optical acrylic.

8. Placido’s discs cone-projector according to claim 1 , characterized in that said inner cone is painted, while each of said stepped perimeters in triangular shape defining the light surface is machined.

9. A hand-held smartphone-assisted keratoscope using the Placido’s discs cone-projector according to claims 1 to 8, characterized by comprising:

a container module in conical shape having a top end connectable to a mobile phone (cell phone) support and a lower end of smaller diameter that faces the patient's eye, both ends being open and inside which there are at least:

said Placido’s discs cone-projector,

a light diffuser panel arranged above said ring cone-projector,

a printed circuit arranged upstream of the light diffuser panel,

a light box containing said printed circuit, and

a closing element.

10. The hand-held smartphone-assisted keratoscope according to claim 9, characterized in that the upper end of said container module has a pair of locking tabs that fit into respective slots provided in said mobile telephone support, being said container module provided, in turn, with at least one light button.

11. The hand-held smartphone-assisted keratoscope according to claim 9, characterized in that said printed circuit is a printed circuit comprising an LED light and a battery.