ES2406380B1 - ORTOQUERATOLOGY CONTACT LENS. - Google Patents

Abstract

The invention relates to a rigid contact lens for therapeutic purposes for the correction of orthokeratology. In particular, it refers to a lens created to mold the central curve of the human eye by increasing it and achieving the correctness of farsightedness thanks to its configuration. To perform corneal molding to correct myopia and astigmatism and, differently, in farsightedness, as is done for correction in the case of myopia and astigmatism, in which the effect of suction is used, but changing it for farsightedness due to the effect of compression.

Description

ORTOQUERATOLOGY CONTACT LENS Object of the Invention

More specifically, the invention relates to a rigid contact lens for therapeutic purposes for the correction of orthokeratology. In particular, it refers to a lens created to mold the central curve of the human eye by increasing it and achieving the correctness of farsightedness thanks to its configuration.

State of the art.

The eye is the basic structure or organ that constitutes the sense of sight. In the human being, the organ of vision is formed by two eyes, located in cavities the eye orbits, in the upper part of the face.

The eyeball has three layers and different

Cameras with different structures. The different structures are responsible for capturing the radiation

light, focus and form the image. The outermost layer of the globe is formed by two membranes, the sclera and the cornea, which are transparent and let light through.

The cornea is a transparent membrane that lines the anterior face of the eyeball, in contact with the air, and that subsequently delimits the anterior chamber of the eye, has a thickness of 0.5 mm. and is endowed with a remarkable refractive power.

It is known to use rigid lenses of reverse geometry in night use to obtain the

molding of the cornea, first surface of the eye and allow normal vision during the day without them.

Existing inverse geometry lenses are defined by having a central curve with a radius greater than the radius of the cornea, and a curve adjacent to the central one that has a radius of curvature less than the radius of the central or optical zone of the lens. This produces a distribution of forces that shape the anterior surface of the eye, reducing its curvature in the event that the eye is affected by myopia, and allowing the correct focus on the retina of distant objects.

These lenses have the disadvantage of hindering the centering of the lens, slowness of correction and limitations that are resolved with the design of the peripheral part of the lens, object of this patent.

As is evident, these lenses are not valid for the correction of farsightedness, since an increase in the cornea curve is necessary! central. There are some previous attempts in the development of lenses for the correction of farsightedness by corneal molding! These designs consist of lenses with the most curved central area that the cornea radius! to thereby induce a curling of the vision zone while the lens is worn during sleep.

Unfortunately

until he Present its effectiveness is

relative

and unpredictable

He

reason by he that others designs current no

they get

results reproducible be understands to

from research work of the owner of that utility model request, where it was discovered that the principles used in the

Corneal molding techniques for myopia are completely opposite to those needed to be able to

make an exact correction in farsightedness.

Orthokeratology lenses that have been used for myopia and astigmatism perform corneal molding through hydrodynamic effects that are created in the tear trapped under the lens. In general it refers to suction forces in areas of tear accumulation. In the case of farsightedness the optimal result is obtained curiously by compression forces in the peripheral areas and precisely any suction force must be eliminated, since in that case what happens is a molding effect that flattens the corneal surface, such as It is the case of myopia and that is the opposite effect to the one sought.

Purpose of the Invention

Perform corneal molding to correct myopia and astigmatism and, differently, in farsightedness, as is done for correction in the case of myopia and astigmatism, in which the effect of suction is used, but by changing it for farsightedness due to the effect of compression.

For this purpose the lens object of the present invention has a peripheral zone different from all the preceding ones, in which although it allows the centering of the lens by means of one or more annular grooves, it also effects the release of compression in the area peripheral, to allow maximum pressure to be located in the central annular area, while allowing the exchange of tear fluid through channels and fenestration.

Description of the Invention

The contact lens object of the present invention has a body as a spherical cap, which has a curvature with the main characteristic that said curvature is always greater and the radius smaller than that of the cornea in the case of farsightedness , while in the case of myopia the radius of curvature is greater than that of the cornea.

The lenses are defined by a set of curves, the central curve being that of the optical zone, a

continuation

follow a set from curves or bands

peripherals

From

between they exist in particular to the less

two, with the characteristics that the first one has a radius of curvature greater than the previous one, and the next curve is of a radius smaller than the one before the first one, thus forming an annular zone of tear accumulation called tear reservoir. The volume of the tear accumulation is calculated according to the desired amount of reduction, since a high volume effects more correction than a smaller volume. Specifically, the height of the reservoir must be the same as that accumulated in the central area of the cornea.

In the case of farsightedness, the pre-last or edge curve has a less curved radius than the previous one and is programmed to make a decreasing and smooth alignment with the corneal periphery, and finally there is a last curve that has a radius much more open than the previous one, and that forms the tear edge meniscus, and allows

tear exchange under the lens at

to blink.

The design may include to improve the tear flow of a hole or fenestration in the optical zone, which is usually 1m.m in size.

may

reach the 4 mm Equally be It includes in he

design

from the channels from one mm from width for he

exchange

tear that go since he edge from the

lens up

the zone optics.

For the investigations carried out by the author, the curvature of the lens is the result of adding the power of the cornea to the value of the ametropia to be corrected plus a constant, whose value is around 30.

Specifically and for the calculation in mm. The standard formula is:

RZOP K- (0.15 x A + 0.30),

Being:

RZOP: the radius of the optical zone.

K: the value of the flat keratometric radius and

A: the ametropia to correct.

Based on the foregoing, we can summarize that the invention achieves the following advantages over the now known lenses:

Greater focus of the lens. Improves the interpretation of the pattern of

fluorescein Increase the speed of lens treatment. Corneal defect corrected in major

proportion.

Other details and features will be revealed in the course of the description given below, in which reference is made to the accompanying drawings, in which an embodiment is shown by way of illustration but not limitation Preferred of the invention.

Description of the figures.

Figure 1 is a schematic side elevation view of the recommended lens (10) adapted to an eyeball.

Figure 2 is a front elevational view of the back of the lens (10).

Figure 3 is a cross section in elevation by A-A 'according to Figure 1 of the lens (10), object of the invention.

Figure 4 is a cross-section in elevation by B-B 'according to Figure 1, of the lens (10), object of the invention.

The

figure no 5 is a section longitudinal of the

body

from the lens (10)

The

figure no 6 is a design alternative from the

face

later (17) from the Len tea (10)

The

figure no 7 is a view in raised side

schematized of a lens (21) designed according to the invention for the correction of myopia. Following is a list of the different parts of the invention that are recorded in the

figure attached with the help of numbers

corresponding; (10) lens, (11) first curve or

band, (12), second curve or band, (13) third

band, (14), channels, (15) fenestration, (16) part

5

front of the lens (10), (17) back of the

lens (10) '(18) optical zone, (19) cornea, (20)

reservoirs, (21) lens for the correction of the

myopia

Description of one of the preferred embodiments of

1 o

the invention .

In one of the preferred embodiments of the

invention and as can be seen in figure 1,

a lens (10) has a configuration body a

spherical cap mode, whose front part (16)

fifteen

as can be seen in figure 2, it is

affected a set of channels (14) ranging from the

optical zone, (18) in the center of the lens, to the

periphery of the lens (10) in alignment substantially

radial, see figure 4.

twenty

The back (17) of the lens (10) in

contact with the cornea (19) as can be seen in

Figure 1 shows a hole or fenestration

(15) as you can in figure 5, which facilitates

the tear flow between the cornea (19) and said

25

back (17) of the lens (10).

Symmetrically to the central or optical zone

(18) there is a first curve (11), whose radius

is greater than the radius of the optical zone (18), which

intersects with a second curve (12), whose radius is

30

less than the radius of the curve (11), the volume

bounded between curves (11-12) and cornea (19,)

set up an annular zone of tear accumulation

indicated in figure 2, called a tear reservoir (2 O).

The third curve (13) see figure 1, has a smaller radius than the curve (12), which is followed by a fourth curve that has a radius greater than that of the previous curve (13).

Alternatively and in which a technical equivalent can be considered, see Figure 6, the back (17) of the lens (10) can have curves (21) before the reservoirs (20), with the special feature that the radius of the curve

(21) is greater than the radius of the optical zone (18). There are therefore several design alternatives for the

face

later (17) varying the position of the curves

(11-12-13)

with the conditioning factors from radio

previously

cited.

Alternatively

between the curves (11-12-13)

a curve (21) of less curvature may be provided than the central zone (18) but radius greater than that of (18).

Described sufficiently the present invention in correspondence with the attached figures, it is easy to understand that any modifications of detail that are deemed convenient may be made therein, provided that the essence of the invention is not altered, which is summarized in the following claims.