University of Alicante

Presbyopia is a widespread problem in the population over 45 years, so it is especially relevant to develop a new multifocal contact lenses based on the optimization of depth of focus through combining different types of optical aberrations, with an easy fitting, with significant positional stability, and customizable according to the specific needs of each patient.

The present invention solves technical problems described above.

In this case, a new multifocal contact lenses has been developed to compensate presbyopia. It is made of oxygen permeable rigid material, with scleral bearing (that is, the outermost and white layer of the eyeball), which is fully customizable according to the specific anatomical properties of the eye of each patient, such as:

• Zernike's third to sixth order aberrations.

• Pupil dynamics.

• Position of the visual axis with respect to the pupillary center.

This novel contact lens, which allows an aligned and adequate fitting to the corneal-conjunctival profile of the patient, comprise three different areas: corneal, limbar and scleral. In turn, each of these areas has two surfaces: anterior (which is in contact with the environment), and posterior (which is the one that configures the tear meniscus retained between the cornea and the contact lens). See Figures 1 and 2.

1. Corneal area (3): it has a variable diameter with a fixed rear surface geometry (3a) and an anterior surface shape (3b) which is modified during the manufacturing process according to the specific needs of the patient (according to the refractive error to correct) and the aberrometric induction required. For such purpose, the radius of the central curvature and the asphericity are modified.

2. Limbar area (2): it has both a diameter and a variable asphericity (a total of 8 options of asphericity are offered to facilitate the fitting of this zone to the cornea-conjunctival transition of each patient). Also, this area is the responsible for the control of the sagittal height of the contact lens.

3. Scleral area (1): it is the area of the contact lens that rests on conjunctiva. It has a spherical geometry and a variable diameter. The radius of curvature of the temporal portion and the nasal portion is different to consider the naso-temporal asymmetry of the corneo-scleral profile.

The contact lenses are made of a gas permeable material (with high oxygen transmissibility) and with a variable overall diameter depending on the iris of the patient.

For the fitting of the contact lens, the following variables (calculated according to the post-lens tear meniscus) should be considered:

a. Refraction of the patient.

b. Near addition.

c. Level of primary and secondary ocular spherical aberration.

d. Pupil dynamics pattern.

e. Kappa angle magnitude.

Different simulations were carried out using the standard ray tracing procedure and assuming different model eyes with different magnitudes of primary spherical aberration, which allowed us to define the most suitable aberrometric profile for the contact lens, providing optimized visual quality and depth of the desired focus, for different eye optical combinations.

A classification has also been made with different levels of decentration of the optical center at the nasal level, depending on the magnitude of the patient's kappa angle.

ADVANTAGES OF THE TECHNOLOGY

The new multifocal scleral contact lens made of oxygen permeable rigid material and with optical personalization for each patient, offers the following advantages over the designs currently on the market:

1. It rests only on the conjunctival-scleral surface (this lens does not bear at any point on the surface of the cornea), minimizing the risk for continuous friction between the lens and the cornea, allowing a fitting providing maximum comfort.

2. It presents a great variety of options to induce stable optical aberrations according to the needs and the optical peculiarities of the patient's eye.

3. It allows an optimization of the depth of focus leading to excellent levels of visual quality.

4. In the case of patients with a peculiar pupil dynamics or a very marked kappa angle, the contact lens can be modified to adapt it to these factors, thus achieving an even greater optimization of the results.

5. The scleral support in the 360º confers a greater stability to the lens, minimizing the movement and the decentration, and therefore contributing to an optimum vision for both near and far.

6. It takes into account the naso-temporal asymmetry of the profile of the corneo-scleral junction, which minimizes both the decentration and the movement of the lens.

7. The fitting of the contact lens is easy, personalized and specific for each patient, providing great levels of comfort and excellent visual quality.

8. The high failure rates provided of current multifocal contact lenses are overcome with this lens.

INNOVATIVE ASPECTS OF THE TECHNOLOGY

A multifocal scleral contact lens has been developed to compensate presbyopia, which is optically customizable according to the specific needs of each patient's eye.

Its development has been based on the optimization of depth of focus by combining different types of optical aberrations that are stable as no decentrations of the lens are expected due to the high stability of the bearing of the lens.

For such purpose, a wide variety of Zernike third to sixth order optical aberration induction options has been used not only according to the patient's near addition, but also according to the patient's kappa angle as well as the pupil size under different lighting conditions.

Therefore, the design has been managed to optimize the depth of focus while maintaining excellent levels of visual quality.

This novel contact lens is easily fitted, even in those patients who have a peculiar pupil dynamics or a marked kappa angle.

In addition, the optical center of this lens can be decentrated as a function of the kappa angle of the patient, thereby preventing high levels of comatic aberration in patients with a large kappa angle (for instance, in nearsighted patients).

Unlike virtually all current multifocal contact lenses, which work with induction of primary spherical aberration, it has been shown that the combination of other types of optical aberrations may induce significant increases in depth of focus without significant deterioration of the visual quality.

This novel multifocal scleral contact lens to compensate presbyopia (eyestrain) has been developed on a laboratory scale.

A batch of prototypes has been manufactured and successfully validated in different patients. The manufacturing process is reliable and reproducible.

Currently, the CE marking is being processed, which will allow its commercialization at international level.

The present invention is framed in the field of Optics. In particular, it relates to a multifocal scleral contact lens to compensate presbyopia. It is optically customizable according to the specific needs of each patient.

It is looking for companies interested in acquiring this invention for commercial exploitation through:

• License agreement.

• Development of new applications.

• Technology and knowledge transfer agreements.

• Carry out technical reports and scientific advice for companies.

• Provide specific training tailored to the needs of the company.Provide technological support in those techniques that require high training or sophisticated instruments that are not available to the requesting company.

• Exchange of personnel for defined periods of time (for learning a technique, etc.).

• Rental of internal equipment to clients who wish to carry out their own tests (own infrastructure of the Department of Optics, Pharmacology and Anatomy, or Technical Research Services (SSTTI) of the University of Alicante).

The present invention is protected through granted patent :

• Title of the patent: "Lente de contacto multifocal escleral".

• Application number: P201631236.

• Application date: 21th September 2016.