The present invention relates to a tonometer cone.

Nowadays several models of tonometer cones, single-use or reusable, are widespread.

The tonometer is an instrument used in ophthalmology to determine the intraocular pressure of an eye of the patient, for example in order to determine whether a glaucoma is present.

In the sector, the most widespread and most precise instrument is the Goldmann applanation tonometer. It is composed of a body, which contains mechanisms within it that are similar to those of a precision scales, and an upper portion, which is constituted by a thin metallic bracket at the end of which a cone is positioned which the ophthalmologist brings into contact with the eye of the patient.

The value of the intraocular pressure is obtained as a function of the resistance offered by the ocular surface.

During use, the cone touches the apex of the cornea and, therefore, at each measurement it needs to be disinfected or, if it is a single-use cone, replaced.

Reusable cones need to be carefully disinfected before every use, washed with running water, dried with a clean cloth and, after use, they need to be re-sterilized to prevent the transmission of pathogens from one patient to another through the lacrimal film.

The drawback of sterilization has now been overcome with the use of single-use cones or of partially single-use cones.

The latter are cones that are provided in two or in three separate parts, of which only the part that comes into contact with the eye of the patient during the examination is single-use. For example, the two parts can be constituted by a tip, the part that comes into contact with the eye, and by a main body to be inserted into the tip. These too are not devoid of drawbacks, because the reduced size of the product, in particular of the tip, make them difficult to handle.

Some types of single-use cones available on the market are completely transparent, to the disadvantage of the image obtained, which is not completely clear owing to the dispersion inside the cone of light rays coming from outside.

In order to overcome this drawback, cones are provided with the central part tinted, or with the side surfaces tinted with a dark color.

The need to offer a single-use cone with which to obtain a clear image has led to the cone disclosed in Italian patent for invention no. 0001407319.

According to the teachings contained in this patent, the cone is single- use and made of plastic material by co-molding a substantially transparent part and an opaque dark part. The first part is preferably made of polymethyl methacrylate (PMMA) or of polymethyl acrylate (PMA), and the second part is preferably made of thermoplastic elastomer.

Structurally, such cone has a first substantially cylindrical portion which constitutes the tip of the cone which comes into contact with the eye of the patient, a second conical portion which is adjacent to the first portion and the smaller-diameter end of which is substantially the continuation of the end of the first portion, opposite to the other end which comes into contact with the eye, and a third substantially cylindrical portion placed adjacent to the second portion so that one end of the third portion is substantially the continuation of the larger-diameter end of the second portion.

Such cone can be easily gripped by the operator, by grasping it at the second or at the third portion.

However, this product too is not devoid of drawbacks.

First of all the fact that the molding of different materials in the same mold implies different cooling times and hence different rates of contraction, which induce tensions and, therefore, size deviations with respect to the design specifications. The measuring surface therefore loses precision and therefore, in order to maintain a certain level of precision of the cone, quality control results in many rejects.

Therefore, the advantage that makes it possible for the production process to produce at low cost is defeated by the waste.

The aim of the present invention is to provide a tonometer cone that is capable of improving the prior art in one or more of the above mentioned aspects.

Within this aim, an object of the invention is to provide a single-use tonometer cone, with high visual quality, in order to obtain an evaluation as correct as possible of the intraocular pressure of the patient, while limiting production rejects and therefore keeping costs down with respect to conventional cones.

Another object of the invention is to provide a tonometer cone that is not only precise and capable of being provided simply and at low cost, but which is also safe for both doctor and patient from the point of view of hygiene and of its sterilization.

A further object of the present invention is to overcome the drawbacks of the prior art in an alternative manner to any existing solutions.

Another object of the invention is to provide a tonometer cone that is highly reliable, easy to implement and at low cost.

This aim and these and other objects which will become better apparent hereinafter are achieved by a tonometer cone according to claim 1 , optionally provided with one or more of the characteristics of the dependent claims.

Further characteristics and advantages of the invention will become better apparent from the detailed description that follows of a preferred, but not exclusive, embodiment of the tonometer cone according to the invention, which is illustrated for the purposes of non-limiting example in the accompanying drawings wherein:

- Figure 1 is a perspective view of the tonometer cone according to the invention;

- Figure 2 is a cross-sectional side view of the tonometer cone according to the invention;

- Figure 3 is a perspective view of the internal part of the tonometer cone according to the invention.

With reference to the figures, the tonometer cone according to the invention, generally designated by the reference numeral 10, comprises an internal part 11 , which is substantially transparent and longitudinally extended, with an end portion 12 which is adapted to make contact with an eye of the patient, and an intermediate portion 14 which is substantially frustum-shaped or cylindrical (frustum-shaped in the example shown). The cone 10 also comprises a covering 13 which is complementary to the intermediate portion 14 and is to be fitted thereon.

Advantageously, the covering 13 is made of a material with antibacterial properties.

As can clearly be seen in Figure 3, the internal part 11 comprises in succession:

- the end portion 12, which is substantially frustum-shaped (or cylindrical in a possible variation),

- the intermediate portion 14, which is frustum-shaped (or cylindrical in a possible variation) and at least partially hollow,

- a substantially cylindrical and hollow final portion 15.

In particular, the end portion 12, if frustum-shaped as in the example shown, has an end, which comes into contact with the eye, of smaller diameter than the end that is adjacent to the intermediate portion 14.

The internal part 11 is preferably made of thermoplastic material, preferably PMMA (polymethylmethacrylate), or alternatively ABS (acrylonitrile butadiene styrene) and the like.

The covering 13 is tinted, preferably with a dark color, and is adapted to coat the intermediate portion 15, and therefore has a complementary hollow frustum shape and is provided by molding plastic material with antibacterial properties.

In particular, it is preferably made of thermoplastic elastomeric material (TPE) with antibacterial properties, of the type known by the trade name MARFRAN.MED®. MARFRAN.MED® is a TPE compound known in the medical and pharmaceutical sector. MARFRAN.MED® is a family of thermoplastic compounds based on SEBS (styrene-ethyl-butyl-styrene) in which usnic acid, an antibiotic of plant origin extracted from some species of lichen, is embedded in the matrix.

At the opposite end from the end intended for contact with the eye of the patient, the end portion 12 with its diameter creates a slight shoulder for the covering 13, thus preventing the separation thereof on the internal part

11 , once fitted over it.

Substantially, the covering element 13 is inserted at the portion 12, and, owing to the presence of the shoulder, is snap-coupled to it by elastic deformation.

The intermediate portion 14 has a greater diameter away from the end portion 12, and at the opposite end from the latter it has a circular protrusion 16.

Therefore the covering 13 fitted over on the internal part 11 is locked between the shoulder and the circular protrusion 16.

The invention also relates to an applanation tonometer cone, which comprises:

- a substantially transparent and longitudinally extended internal part, with an end portion adapted to make contact with an eye of the patient, and a substantially frustum-shaped or cylindrical intermediate portion,

- a covering for at least the intermediate portion which is constituted by a colored and/or adhesive film with antibacterial properties.

The covering is again tinted and preferably dark in color.

During production, the internal part is obtained by hot-runner injection of plastic material in the cavity of a mold, which makes it possible to bring the material to the mold in liquid form. The injector used is relatively small, is controlled by an injection molding machine, and is capable of opening and closing at the appropriate time in order to control the introduction of thermoplastic material. This solution makes it possible to eliminate much of the filling sprues, with considerable saving of waste material.

Furthermore, the apparatus should be preferably provided with occlusion pins, which advantageously ensure: the absence of cold material from the previous molding, constant and balanced filling (where the mold has multiple cavities, this makes it possible to deposit the same quantity of product in all the impressions), an injection point clean and free from filaments, shorter mold filling times (therefore also a shorter production cycle), and lower injection pressures with consequent longer lifetime of the mold.

It should also be noted that providing the cone in two separate parts that are subsequently coupled makes it possible to prevent the phenomenon of withdrawal of cones made by co-molding the two materials, considerably reducing the number of pieces to be rejected.

The tonometer cone according to the invention is single-use and is offered in single packages or in blister packs. To use it, the cone is freed from the package and applied by the operator to the tonometer. In this step of manipulation, the antibacterial material of the covering 13 prevents the transfer of contagious bacteria between patients and operators.

Use of the cone according to the invention is evident from the foregoing description and explanation.

In particular, it is evident that the external covering, being made of plastic material that is dark in color and has antibacterial properties, is capable not only of protecting the internal part from any light beams coming from outside, in order to obtain a clear image, but also of protecting the patient from contamination events that could occur after the extraction of the cone from the sterile package.

In practice it has been found that the invention fully achieves the intended aim and objects, providing a tonometer cone with high visual quality and safety from the hygienic point of view, which at the same time can be produced with fewer rejects with respect to conventional cones.

The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Moreover, all the details may be substituted by other, technically equivalent elements.

In practice the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. 102017000116091 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.