Patent Publication Number: US-2003231283-A1

Title: Integrated test pupil device for corneal topography

Description:
BACKGROUND OF THE INVENTION  
       [0001] This invention is concerned with Corneal topography and an integrated test pupil device. More specifically, the test pupil device comprises a video camera in sequence with an optical group including lenses and a Placido disk.  
       [0002] 1. Description of Prior Art  
       [0003] It is known that a test of a cornea or of a pupil is basically in the field of ophthalmology. In fact the acquisited or acquired data for this test are particularly important both from a diagnostic point of view in order to have extremely precise data before performing a refractive surgery operation.  
       [0004] According to the prior art shown in FIG. 1, the cornea examination is carried out by a device known as a corneal topography device.  
       [0005] The known device as illustrated in FIG. 1 comprises a videocamera  1  for taking out an image or receiving an image coming from or transmitted through lens  2  and lens  3 . This device also includes a fixing LED (light-emitting diode)  4  proximate to camera  1  and a glass semi-silver plated plate  5  so that the light from the LED  4  is reflected onto a silver-plated wall of the glass semi-silver-plated plate  5 .  
       [0006] One or more neon glow lamps  6  is provided which during its ignition will light up the Placido disk or keratography  7  fixed by means of fasteners  8  to frame  9  which forms part of the corneal topography device. Outwardly of frame  9  and to the rear of videocamera  1  and on a front portion of the frame, a small monitor  10  is placed proximate to and connected to videocamera  1  by means of connection wire  11  to permit a prompt visualization of what is visualized or visualisated.  
       [0007] Wire  11  which is for the acquisition of acquired data is then connected with a second monitor and with a conventional computer, not shown.  
       [0008] During the functioning and operation of the corneal topography device, the patient&#39;s eye generally designated  12  is placed in an examining position and wire  13  is connected to LED  4  and wire  14  is connected to the semi-silver-plated plate  5  to provide for the electrical connections of neon glow lamps  6 .  
       [0009] During the operation of the prior art corneal topography device  20 , plate  5  is lit up by LED&#39;s  4  and reflects on its outside part what the patient or more specifically what the patient&#39;s eye observes, and that is the fixing centre.  
       [0010] In this situation and the operation of the prior art device  20 , there is formed onto the cornea an image that is known as the first Purchinjè image, which is a digital image. This Purchinjè image, which is taken to the optic of the system, is then filmed by the videocamera  1 , and the videocamera also sends the same digital image to the small monitor  10  by means of wire  11 .  
       [0011] The digital images are then sent to a computer with a system software which permits the elaboration of the digital images.  
       BRIEF SUMMARY OF THE INVENTION  
       [0012] The invented device is an improvement over the aforenoted prior art device  20  and in comparison provides for actuation of and obtaining the images with a normal solution in use between the bigger or larger part of the manufacturers and provides for or permits actuation with only one device for the pupil test as well.  
       [0013] It is of particular and great importance, in that the device of the present invention is able to point out and determine the actual pupil centre on the light alteration, which as understood is changeable from patient to patient.  
       [0014] Another feature of particular importance is that the same device is able to determine without any image interruption, the pupil morphology. This pupil morphology data is also changeable and peculiar to each patient.  
       [0015] Practically the device according to the invention is able to film pupil variations with different light conditions, and it is able to elaborate the area of the same pupil, and it is able to set for each light condition the pupil centre for each examined eye.  
       [0016] Accordingly, on this basis the same device can contemporaneously provide both the fixing centre and the pupil centre.  
       [0017] The acquisition of these points are distinct and separate, and it is of fundamental importance for a refractive surgery operation which is generally treated with a laser.  
       [0018] It is known that in these operations, an eximer laser is generally used. An eximer laser instrument is extremely precise so that there is the ability to avail oneself of two data sources. The ability to avail oneself of two data sources clearly provides for better operation results in comparison with those obtained when considering for these purposes the operation only of the fixing point and not knowing, in this situation, in such a continuous operation, the area variability of the pupil and consequently the precise centre of the pupil.  
       [0019] In fact, the pupil areas change from a maximum value, obtained without light, to a minimum value obtained with the highest quantity of light that the lamp presents inside the device. Clearly always when considering the keratometric axis, the patient will always observe the fixing point.  
       [0020] Obviously, by means of the videocamera filming, it is possible to know and ascertain all of the intermediate positions that are memorized so as to enable use for any computer elaboration. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0021]FIG. 1 is a transverse sectional view of the corneal topography device of the prior art.  
     [0022]FIG. 2 is a perspective view of the corneal topography device according to the invention, together with related parts of an operational machine.  
     [0023] FIG. 3  is a longitudinal sectional view of one embodiment of the invention passing through the center of the Placido disk  19  as illustrated in FIG. 2.  
     [0024]FIG. 4 is a transverse sectional view taken along section line A-A of FIG. 3.  
     [0025]FIG. 5 is a longitudinal sectional view of another embodiment of the invention, similar to FIG. 3 and illustrating in particular LED  10   a.    
     [0026]FIG. 6 is a longitudinal sectional view of another embodiment according to the invention similar to FIG. 3 and illustrating in particular LED  10   b ; and  
     [0027]FIG. 7 is a longitudinal sectional view of another embodiment according to the inventions, similar to FIG. 3 and illustrating in particular LED  10   c.   
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0028] Referring now more particularly to the accompanying drawings, and in particular to FIGS.  2  to  7  in which like reference numerals designate the same parts in the different embodiments of FIGS.  2  to  7 . In addition, some of the parts of the invention in common with the prior art in FIG. 1 are accorded the same reference numeral, and in other instances different numerals were used in FIGS.  2  to  7  to relate the parts to the present invention for ease of explanation.  
     [0029] The corneal topography device  20 , according to the present invention comprises videocamera  1  as in the prior art in sequence and aligned with the optical group including lens  2  and lens  3 .  
     [0030] Then in accordance with a first embodiment as shown in FIG. 3, according to the invention, a fixing LED  114  and an infrared fixing LED  115  with a neon glow lamp  6  with two beam splitter plates  17  and  18  are provided proximate to the neon glow lamp  6 .  
     [0031] A conventional Placido disk or keratograhy  19  is provided having on the outside of the corneal topography device  120  two laterally positioned infrared LED&#39;s  110 . The LED&#39;s  110  are placed in this position so as to be able to provide a grazing light for the pupil test. It is noted that the Placido disk  19  is outside of lens or remote from the rays transmitted through lenses  2  and  3  to camera  1 . LED&#39;s  110  and fixing LED  115  are both infrared so as not to interfere with the light sources which are used for the cornea test.  
     [0032] In fact, for this test, frequencies in the visible light field are used. The Placido disk  19  is mounted, by means of bolts  111 , to the frame or body  112  of device  120  which serves as a housing, and the bolts  111  form a semi-arcuate configuration around the outer portion of Placido disk  119 .  
     [0033] On the outside of housing  112 , there is provided small monitor  113  in FIGS.  2  to  7 , and this monitor is similar to device monitor  10  in FIG. 1, and the monitor  113  and is connected to the videocamera  1  by wire  214 , in FIGS.  2  to  7 .  
     [0034] Wire  214  also provides for and permits the sending of the signal from camera  1  to a second outside monitor connected with a computer provided with a system software able to elaborate the images.  
     [0035] The various LED&#39;s are connected with each other and by wires  215  and provide a network connection. Also, the neon glow lamps  6  are connected by wire  116  to a potentiometer  117  to provide for the variability of the luminous intensity.  
     [0036] During the use of the topography according to the invention, the patient&#39;s eye  118  to be tested is therefore contemporaneously or simultaneously subjected to the cornea test and to the pupil test.  
     [0037] Within the art of the invented topography device the infrared LED&#39;s, designated in FIG. 3 can  110  also to be located or provided in different positions on the basis of the use and necessity.  
     [0038]FIG. 5 shows a second embodiment in which infrared LED&#39;s  110   a  are placed inside the device  130  on the Placido disk  19 . The LED&#39;s  110   a  are spaced peripherally along the Placido disk # 19  and are spaced from the center or axial center of the disk and proximate but spaced from the inner walls of the housing or frame  112 .  
     [0039] Referring now more particularly to FIG. 6 which shows a third embodiment of the device designated  140 , a set of infrared LED&#39;s  110   b  are provided in a parallel position in comparison with or relative to glow lamp  6 . These LED&#39;s  110   b  are placed between the semi-silver plated glass or wall  5  and lens  3 , on the side of the silver plated wall  5  remote from Placido disk  118 .  
     [0040] In a fourth embodiment the device is designated  150 , as best seen in FIG. 7, and only one infrared LED  110   c  is provided together with a beam splitter plate  110   d  having the same function as the beam splitter plate  18  previous application.  
     [0041] LED  110   c  is positioned between semi-silver plated plate  5  and the Placido disk.  
     [0042] The invented device is illustrated in the different embodiments and in an indicative way is not limited to the details or specifics as shown in the various different embodiments illustrated FIGS.  2 - 7  of the drawings.  
     [0043] While there has been shown what is considered to be the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention.  
     [0044] 1 . video camera  
     [0045] 2 . lens  
     [0046] 3 . lens  
     [0047] 4 . LED  
     [0048] 5 . semi-silver-plated wall/glass  
     [0049] 6 . new glow lamps  
     [0050] 7 . Placido disk or Kerotography—fixed  
     [0051] 8 . fasteners  
     [0052] 9 . frame  
     [0053] 10 . Monitor  
     [0054] 10 . FIG. 3 
     [0055] 10   a . LED FIG. 5 
     [0056] 10   b . LED FIG. 6 
     [0057] 10   c  LED FIG. 7 
     [0058] 11 . connection wire  
     [0059] 12 . eye—FIG. 2  
     [0060] 13 . electrical wire  
     [0061] 14 . fixing LED  
     [0062] 15 . infrared fixing LED  
     [0063] 16 . wire  
     [0064] 17 . beam splitter plate  
     [0065] 18 . beam splitter plate  
     [0066] 20  corneal prior art device  
     [0067] 110  LED  
     [0068] 111 . Bolts  
     [0069] 112 . device frame or body  
     [0070] 113 . monitor  
     [0071] 114 . wire  
     [0072] 115 . wires  
     [0073] 116 . wires  
     [0074] 117 . potentiometer  
     [0075] 120 . Corneal topography device  
     [0076] 130 . 2 nd  embodying  10   a  is on inside of device